refactor: rework fs error system

.gitignore

@@ -14,9 +14,11 @@
 
 !/.gitignore
 !/.gitattributes
-!/build.js
 !/LICENSE
 !/README.md
 !/settings.gradle
 !/build.gradle
 !/gradle.properties
+!/gradle
+!/gradle/wrapper
+!/gradle/wrapper/gradle-wrapper.properties

build.gradle

@@ -1,37 +1,32 @@
 plugins {
-    id 'application'
+    id "application"
 }
 
 java {
     sourceCompatibility = JavaVersion.VERSION_11
     targetCompatibility = JavaVersion.VERSION_11
+    toolchain.languageVersion = JavaLanguageVersion.of(11)
+    withSourcesJar()
 }
 
 jar {
-    manifest {
-        attributes (
-            'Main-Class': project.main_class
-        )
-    }
+    manifest.attributes["Main-class"] = project.main_class
 }
 
 sourceSets {
-    main.java.srcDirs = [ 'src/java' ]
-    main.resources.srcDirs = [ 'src/assets' ]
+    main.java.srcDirs = [ "src/java" ]
+    main.resources.srcDirs = [ "src/assets" ]
 }
 
 processResources {
-    filesMatching('metadata.json') {
-        expand (
-            'version': project.project_version,
-            'name': project.project_name
+    filesMatching "metadata.json", {
+        expand(
+            version: project.project_version,
+            name: project.project_name
         )
     }
 }
 
-application {
-    mainClass = project.main_class
-}
-
-archivesBaseName = project.project_name
-version = project.project_version
+base.archivesName = project.project_name
+version = project.project_version
+group = project.project_group

gradle.properties

@@ -1,3 +1,4 @@
+project_group = me.topchetoeu
 project_name = jscript
-project_version = 0.8.4-beta
+project_version = 0.8.6-beta
 main_class = me.topchetoeu.jscript.utils.JScriptRepl

gradle/wrapper/gradle-wrapper.properties

@@ -0,0 +1,7 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.5-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists

settings.gradle

@@ -0,0 +1,5 @@
+plugins {
+    id 'org.gradle.toolchains.foojay-resolver-convention' version '0.7.0'
+}
+
+rootProject.name = properties.project_name

src/java/me/topchetoeu/jscript/common/Filename.java

@@ -7,22 +7,17 @@ public class Filename {
     public final String protocol;
     public final String path;
 
-    public String toString() {
+    @Override public String toString() {
         return protocol + "://" + path;
     }
-
-    @Override
-    public int hashCode() {
+    @Override public int hashCode() {
         final int prime = 31;
         int result = 1;
         result = prime * result + protocol.hashCode();
         result = prime * result + path.hashCode();
         return result;
     }
-
-
-    @Override
-    public boolean equals(Object obj) {
+    @Override public boolean equals(Object obj) {
         if (this == obj) return true;
         if (obj == null) return false;
         if (getClass() != obj.getClass()) return false;
@@ -41,9 +36,6 @@ public class Filename {
         return true;
     }
 
-
-
-
     public Filename(String protocol, String path) {
         path = path.trim();
         protocol = protocol.trim();

src/java/me/topchetoeu/jscript/core/engine/values/Values.java

@@ -711,14 +711,14 @@ public class Values {
                 res.append("{\n");
 
                 for (var el : obj.values.entrySet()) {
-                    for (int i = 0; i < tab + 1; i++) System.out.print("    ");
+                    for (int i = 0; i < tab + 1; i++) res.append("    ");
                     res.append(toReadable(ctx, el.getKey(), passed, tab + 1));
                     res.append(": ");
                     res.append(toReadable(ctx, el.getValue(), passed, tab + 1));
                     res.append(",\n");
                 }
                 for (var el : obj.properties.entrySet()) {
-                    for (int i = 0; i < tab + 1; i++) System.out.print("    ");
+                    for (int i = 0; i < tab + 1; i++) res.append("    ");
                     res.append(toReadable(ctx, el.getKey(), passed, tab + 1));
                     res.append(": [prop],\n");
                 }

src/java/me/topchetoeu/jscript/lib/ConsoleLib.java

@@ -0,0 +1,38 @@
+package me.topchetoeu.jscript.lib;
+
+import java.io.IOException;
+
+import me.topchetoeu.jscript.core.engine.values.Values;
+import me.topchetoeu.jscript.utils.filesystem.File;
+import me.topchetoeu.jscript.utils.interop.Arguments;
+import me.topchetoeu.jscript.utils.interop.Expose;
+import me.topchetoeu.jscript.utils.interop.WrapperName;
+
+@WrapperName("Console")
+public class ConsoleLib {
+    public static interface Writer {
+        void writeLine(String val) throws IOException;
+    }
+
+    private File file;
+
+    @Expose
+    public void __log(Arguments args) {
+        var res = new StringBuilder();
+        var first = true;
+        
+        for (var el : args.args) {
+            if (!first) res.append(" ");
+            first = false;
+            res.append(Values.toReadable(args.ctx, el).getBytes());
+        }
+
+        for (var line : res.toString().split("\n", -1)) {
+            file.write(line.getBytes());
+        }
+    }
+
+    public ConsoleLib(File file) {
+        this.file = file;
+    }
+}

src/java/me/topchetoeu/jscript/lib/FileLib.java

@@ -10,12 +10,12 @@ import me.topchetoeu.jscript.utils.interop.WrapperName;
 
 @WrapperName("File")
 public class FileLib {
-    public final File file;
+    public final File fd;
 
     @Expose public PromiseLib __pointer(Arguments args) {
         return PromiseLib.await(args.ctx, () -> {
             try {
-                return file.seek(0, 1);
+                return fd.seek(0, 1);
             }
             catch (FilesystemException e) { throw e.toEngineException(); }
         });
@@ -23,9 +23,9 @@ public class FileLib {
     @Expose public PromiseLib __length(Arguments args) {
         return PromiseLib.await(args.ctx, () -> {
             try {
-                long curr = file.seek(0, 1);
-                long res = file.seek(0, 2);
-                file.seek(curr, 0);
+                long curr = fd.seek(0, 1);
+                long res = fd.seek(0, 2);
+                fd.seek(curr, 0);
                 return res;
             }
             catch (FilesystemException e) { throw e.toEngineException(); }
@@ -38,8 +38,8 @@ public class FileLib {
             try {
                 var buff = new byte[n];
                 var res = new ArrayValue();
-                int resI = file.read(buff);
-    
+                int resI = fd.read(buff);
+
                 for (var i = resI - 1; i >= 0; i--) res.set(args.ctx, i, (int)buff[i]);
                 return res;
             }
@@ -53,7 +53,7 @@ public class FileLib {
                 var res = new byte[val.size()];
 
                 for (var i = 0; i < val.size(); i++) res[i] = (byte)Values.toNumber(args.ctx, val.get(i));
-                file.write(res);
+                fd.write(res);
 
                 return null;
             }
@@ -62,7 +62,7 @@ public class FileLib {
     }
     @Expose public PromiseLib __close(Arguments args) {
         return PromiseLib.await(args.ctx, () -> {
-            file.close();
+            fd.close();
             return null;
         });
     }
@@ -72,13 +72,13 @@ public class FileLib {
             var whence = args.getInt(1);
 
             try {
-                return file.seek(ptr, whence);
+                return fd.seek(ptr, whence);
             }
             catch (FilesystemException e) { throw e.toEngineException(); }
         });
     }
 
-    public FileLib(File file) {
-        this.file = file;
+    public FileLib(File fd) {
+        this.fd = fd;
     }
 }

src/java/me/topchetoeu/jscript/lib/FilesystemLib.java

@@ -8,13 +8,14 @@ import me.topchetoeu.jscript.core.engine.Context;
 import me.topchetoeu.jscript.core.engine.values.ObjectValue;
 import me.topchetoeu.jscript.core.engine.values.Values;
 import me.topchetoeu.jscript.core.exceptions.EngineException;
+import me.topchetoeu.jscript.utils.filesystem.ActionType;
 import me.topchetoeu.jscript.utils.filesystem.EntryType;
+import me.topchetoeu.jscript.utils.filesystem.ErrorReason;
 import me.topchetoeu.jscript.utils.filesystem.File;
 import me.topchetoeu.jscript.utils.filesystem.FileStat;
 import me.topchetoeu.jscript.utils.filesystem.Filesystem;
 import me.topchetoeu.jscript.utils.filesystem.FilesystemException;
 import me.topchetoeu.jscript.utils.filesystem.Mode;
-import me.topchetoeu.jscript.utils.filesystem.FilesystemException.FSCode;
 import me.topchetoeu.jscript.utils.interop.Arguments;
 import me.topchetoeu.jscript.utils.interop.Expose;
 import me.topchetoeu.jscript.utils.interop.ExposeField;
@@ -50,11 +51,10 @@ public class FilesystemLib {
 
             try {
                 if (fs.stat(path).type != EntryType.FILE) {
-                    throw new FilesystemException(path, FSCode.NOT_FILE);
+                    throw new FilesystemException(ErrorReason.DOESNT_EXIST, "Not a file").setAction(ActionType.OPEN);
                 }
 
-                var file = fs.open(path, _mode);
-                return new FileLib(file);
+                return new FileLib(fs.open(path, _mode));
             }
             catch (FilesystemException e) { throw e.toEngineException(); }
         });
@@ -75,7 +75,7 @@ public class FilesystemLib {
                         var path = fs.normalize(args.getString(0));
 
                         if (fs.stat(path).type != EntryType.FOLDER) {
-                            throw new FilesystemException(path, FSCode.NOT_FOLDER);
+                            throw new FilesystemException(ErrorReason.DOESNT_EXIST, "Not a directory").setAction(ActionType.OPEN);
                         }
 
                         file = fs.open(path, Mode.READ);

src/java/me/topchetoeu/jscript/lib/Internals.java

@@ -1,9 +1,7 @@
 package me.topchetoeu.jscript.lib;
 
-import java.io.IOException;
 import java.util.HashMap;
 
-import me.topchetoeu.jscript.common.Reading;
 import me.topchetoeu.jscript.core.engine.Context;
 import me.topchetoeu.jscript.core.engine.Environment;
 import me.topchetoeu.jscript.core.engine.scope.GlobalScope;
@@ -34,27 +32,6 @@ public class Internals {
         else throw EngineException.ofError("Modules are not supported.");
     }
 
-    @Expose(target = ExposeTarget.STATIC)
-    public static Object __log(Arguments args) {
-        for (var arg : args.args) {
-            Values.printValue(args.ctx, arg);
-            System.out.print(" ");
-        }
-        System.out.println();
-
-        return args.get(0);
-    }
-    @Expose(target = ExposeTarget.STATIC)
-    public static String __readline() {
-        try {
-            return Reading.readline();
-        }
-        catch (IOException e) {
-            e.printStackTrace();
-            return null;
-        }
-    }
-
     @Expose(target = ExposeTarget.STATIC)
     public static Thread __setTimeout(Arguments args) {
         var func = args.convert(0, FunctionValue.class);
@@ -175,6 +152,8 @@ public class Internals {
         glob.define(null, "Encoding", false, wp.getNamespace(EncodingLib.class));
         glob.define(null, "Filesystem", false, wp.getNamespace(FilesystemLib.class));
 
+        glob.define(false, wp.getConstr(FileLib.class));
+
         glob.define(false, wp.getConstr(DateLib.class));
         glob.define(false, wp.getConstr(ObjectLib.class));
         glob.define(false, wp.getConstr(FunctionLib.class));

src/java/me/topchetoeu/jscript/utils/JScriptRepl.java

@@ -24,6 +24,7 @@ import me.topchetoeu.jscript.utils.filesystem.MemoryFilesystem;
 import me.topchetoeu.jscript.utils.filesystem.Mode;
 import me.topchetoeu.jscript.utils.filesystem.PhysicalFilesystem;
 import me.topchetoeu.jscript.utils.filesystem.RootFilesystem;
+import me.topchetoeu.jscript.utils.filesystem.STDFilesystem;
 import me.topchetoeu.jscript.utils.modules.ModuleRepo;
 import me.topchetoeu.jscript.utils.permissions.PermissionsManager;
 import me.topchetoeu.jscript.utils.permissions.PermissionsProvider;
@@ -108,6 +109,7 @@ public class JScriptRepl {
         var fs = new RootFilesystem(PermissionsProvider.get(environment));
         fs.protocols.put("temp", new MemoryFilesystem(Mode.READ_WRITE));
         fs.protocols.put("file", new PhysicalFilesystem("."));
+        fs.protocols.put("std", STDFilesystem.ofStd(System.in, System.out, System.err));
 
         environment.add(PermissionsProvider.ENV_KEY, PermissionsManager.ALL_PERMS);
         environment.add(Filesystem.ENV_KEY, fs);

src/java/me/topchetoeu/jscript/utils/filesystem/ActionType.java

@@ -0,0 +1,28 @@
+package me.topchetoeu.jscript.utils.filesystem;
+
+public enum ActionType {
+    UNKNOWN(0, "An operation performed upon", "An operation was performed upon"),
+    READ(1, "Reading from", "Read from"),
+    WRITE(2, "Writting to", "Wrote to"),
+    SEEK(3, "Seeking in", "Sought in"),
+    CLOSE(4, "Closing", "Closed"),
+    STAT(5, "Stat of", "Statted"),
+    OPEN(6, "Opening", "Opened"),
+    CREATE(7, "Creating", "Created"),
+    DELETE(8, "Deleting", "Deleted"),
+    CLOSE_FS(9, "Closing filesystem", "Closed filesystem");
+
+    public final int code;
+    public final String continuous, past;
+
+    public String readable(boolean usePast) {
+        if (usePast) return past;
+        else return continuous;
+    }
+
+    private ActionType(int code, String continuous, String past) {
+        this.code = code;
+        this.continuous = continuous;
+        this.past = past;
+    }
+}

src/java/me/topchetoeu/jscript/utils/filesystem/BaseFile.java

@@ -0,0 +1,59 @@
+package me.topchetoeu.jscript.utils.filesystem;
+
+public abstract class BaseFile<T> implements File {
+    private T handle;
+    private Mode mode;
+
+    protected final T handle() {
+        return handle;
+    }
+
+    protected abstract int onRead(byte[] buff);
+    protected abstract void onWrite(byte[] buff);
+    protected abstract long onSeek(long offset, int pos);
+    protected abstract boolean onClose();
+
+    @Override public int read(byte[] buff) {
+        try {
+            if (handle == null) throw new FilesystemException(ErrorReason.CLOSED);
+            if (!mode.readable) throw new FilesystemException(ErrorReason.NO_PERMISSION, "File not open for reading.");
+            return onRead(buff);
+        }
+        catch (FilesystemException e) { throw e.setAction(ActionType.READ); }
+    }
+    @Override public void write(byte[] buff) {
+        try {
+            if (handle == null) throw new FilesystemException(ErrorReason.CLOSED);
+            if (!mode.writable) throw new FilesystemException(ErrorReason.NO_PERMISSION, "File not open for writting.");
+            onWrite(buff);
+        }
+        catch (FilesystemException e) { throw e.setAction(ActionType.WRITE); }
+    }
+    @Override public long seek(long offset, int pos) {
+        try {
+            if (handle == null) throw new FilesystemException(ErrorReason.CLOSED);
+            if (!mode.writable) throw new FilesystemException(ErrorReason.NO_PERMISSION, "File not open for seeking.");
+            return onSeek(offset, pos);
+        }
+        catch (FilesystemException e) { throw e.setAction(ActionType.SEEK); }
+    }
+    @Override public boolean close() {
+        if (handle != null) {
+            try {
+                var res = onClose();
+                handle = null;
+                mode = Mode.NONE;
+                return res;
+            }
+            catch (FilesystemException e) { throw e.setAction(ActionType.CLOSE); }
+        }
+        else return false;
+    }
+
+    public BaseFile(T handle, Mode mode) {
+        this.mode = mode;
+        this.handle = handle;
+
+        if (mode == Mode.NONE) this.handle = null;
+    }
+}

src/java/me/topchetoeu/jscript/utils/filesystem/ErrorReason.java

@@ -0,0 +1,23 @@
+package me.topchetoeu.jscript.utils.filesystem;
+
+public enum ErrorReason {
+    UNKNOWN(0, "failed", false),
+    NO_PERMISSION(1, "is not allowed", false),
+    CLOSED(1, "that was closed", true),
+    UNSUPPORTED(2, "is not supported", false),
+    ILLEGAL_ARGS(3, "with illegal arguments", true),
+    DOESNT_EXIST(4, "that doesn't exist", true),
+    ALREADY_EXISTS(5, "that already exists", true),
+    ILLEGAL_PATH(6, "with illegal path", true),
+    NO_PARENT(7, "with a missing parent folder", true);
+
+    public final int code;
+    public final boolean usePast;
+    public final String readable;
+
+    private ErrorReason(int code, String readable, boolean usePast) {
+        this.code = code;
+        this.readable = readable;
+        this.usePast = usePast;
+    }
+}

src/java/me/topchetoeu/jscript/utils/filesystem/File.java

@@ -1,22 +1,44 @@
 package me.topchetoeu.jscript.utils.filesystem;
 
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.util.Iterator;
+import java.util.LinkedList;
+
 import me.topchetoeu.jscript.common.Buffer;
-
 public interface File {
-    int read(byte[] buff);
-    void write(byte[] buff);
-    long seek(long offset, int pos);
-    void close();
+    default int read(byte[] buff) { throw new FilesystemException(ErrorReason.UNSUPPORTED).setAction(ActionType.READ); }
+    default void write(byte[] buff) { throw new FilesystemException(ErrorReason.UNSUPPORTED).setAction(ActionType.WRITE); }
+    default long seek(long offset, int pos) { throw new FilesystemException(ErrorReason.UNSUPPORTED).setAction(ActionType.SEEK); }
+    default boolean close() { return false; }
 
+    default byte[] readAll() {
+        var parts = new LinkedList<byte[]>();
+        var buff = new byte[1024];
+        var size = 0;
+
+        while (true) {
+            var n = read(buff);
+            if (n == 0) break;
+
+            parts.add(buff);
+            size += n;
+        }
+
+        buff = new byte[size];
+
+        var i = 0;
+
+        for (var part : parts) {
+            System.arraycopy(part, 0, buff, i, part.length);
+            i += part.length;
+        }
+
+        return buff;
+    }
     default String readToString() {
-        long len = seek(0, 2);
-        if (len < 0) return null;
-        seek(0, 0);
-
-        byte[] res = new byte[(int)len];
-        len = read(res);
-
-        return new String(res);
+        return new String(readAll());
     }
     default String readLine() {
         var res = new Buffer();
@@ -34,4 +56,106 @@ public interface File {
         }
         return new String(res.data());
     }
+
+    public static File ofStream(InputStream str) {
+        return new File() {
+            @Override public int read(byte[] buff) {
+                try {
+                    try { return str.read(buff); }
+                    catch (NullPointerException e) { throw new FilesystemException(ErrorReason.ILLEGAL_ARGS, e.getMessage()); }
+                    catch (IOException e) { throw new FilesystemException(ErrorReason.UNKNOWN, e.getMessage()); }
+                }
+                catch (FilesystemException e) { throw e.setAction(ActionType.READ); }
+            }
+        };
+    }
+    public static File ofStream(OutputStream str) {
+        return new File() {
+            @Override public void write(byte[] buff) {
+                try {
+                    try { str.write(buff); }
+                    catch (NullPointerException e) {throw new FilesystemException(ErrorReason.ILLEGAL_ARGS, e.getMessage()); }
+                    catch (IOException e) { throw new FilesystemException(ErrorReason.UNKNOWN, e.getMessage()); }
+                }
+                catch (FilesystemException e) { throw e.setAction(ActionType.WRITE); }
+            }
+        };
+    }
+    public static File ofLineWriter(LineWriter writer) {
+        var buff = new Buffer();
+        return new File() {
+            @Override public void write(byte[] val) {
+                try {
+                    if (val == null) throw new FilesystemException(ErrorReason.ILLEGAL_ARGS, "Given buffer is null.");
+    
+                    for (var b : val) {
+                        if (b == '\n') {
+                            try {
+                                writer.writeLine(new String(buff.data()));
+                            }
+                            catch (IOException e) {
+                                throw new FilesystemException(ErrorReason.UNKNOWN, e.getMessage());
+                            }
+                        }
+                        else buff.append(b);
+                    }
+                }
+                catch (FilesystemException e) { throw e.setAction(ActionType.WRITE); }
+            }
+        };
+    }
+    public static File ofLineReader(LineReader reader) {
+        return new File() {
+            private int offset = 0;
+            private byte[] prev = new byte[0];
+
+            @Override
+            public int read(byte[] buff) {
+                try {
+                    if (buff == null) throw new FilesystemException(ErrorReason.ILLEGAL_ARGS, "Given buffer is null.");
+                    var ptr = 0;
+
+                    while (true) {
+                        if (prev == null) break;
+                        if (offset >= prev.length) {
+                            try {
+                                var line = reader.readLine();
+
+                                if (line == null) {
+                                    prev = null;
+                                    break;
+                                }
+                                else prev = (line + "\n").getBytes();
+
+                                offset = 0;
+                            }
+                            catch (IOException e) {
+                                throw new FilesystemException(ErrorReason.UNKNOWN, e.getMessage());
+                            }
+                        }
+
+                        if (ptr + prev.length - offset > buff.length) {
+                            var n = buff.length - ptr;
+                            System.arraycopy(prev, offset, buff, ptr, buff.length - ptr);
+                            offset += n;
+                            ptr += n;
+                            break;
+                        }
+                        else {
+                            var n = prev.length - offset;
+                            System.arraycopy(prev, offset, buff, ptr, n);
+                            offset += n;
+                            ptr += n;
+                        }
+                    }
+
+                    return ptr;
+                }
+                catch (FilesystemException e) { throw e.setAction(ActionType.READ); }
+            }
+        };
+    }
+    public static File ofIterator(Iterator<String> it) {
+        return ofLineReader(LineReader.ofIterator(it));
+    }
 }

src/java/me/topchetoeu/jscript/utils/filesystem/FileStat.java

@@ -5,6 +5,9 @@ public class FileStat {
     public final EntryType type;
 
     public FileStat(Mode mode, EntryType type) {
+        if (mode == Mode.NONE) type = EntryType.NONE;
+        if (type == EntryType.NONE) mode = Mode.NONE;
+
         this.mode = mode;
         this.type = type;
     }

src/java/me/topchetoeu/jscript/utils/filesystem/Filesystem.java

@@ -6,10 +6,11 @@ import me.topchetoeu.jscript.core.engine.values.Symbol;
 public interface Filesystem {
     public static final Symbol ENV_KEY = Symbol.get("Environment.fs");
 
-    String normalize(String... path);
-    File open(String path, Mode mode) throws FilesystemException;
-    void create(String path, EntryType type) throws FilesystemException;
-    FileStat stat(String path) throws FilesystemException;
+    default String normalize(String... path) { return Paths.normalize(path); }
+    default boolean create(String path, EntryType type) { throw new FilesystemException(ErrorReason.UNSUPPORTED).setAction(ActionType.CREATE); }
+    File open(String path, Mode mode);
+    FileStat stat(String path);
+    void close();
 
     public static Filesystem get(Extensions exts) {
         return exts.get(ENV_KEY);

src/java/me/topchetoeu/jscript/utils/filesystem/FilesystemException.java

@@ -1,57 +1,90 @@
 package me.topchetoeu.jscript.utils.filesystem;
 
+import java.util.ArrayList;
+
 import me.topchetoeu.jscript.core.engine.values.Values;
 import me.topchetoeu.jscript.core.exceptions.EngineException;
 
 public class FilesystemException extends RuntimeException {
-    public static enum FSCode {
-        DOESNT_EXIST(0x1),
-        NOT_FILE(0x2),
-        NOT_FOLDER(0x3),
-        NO_PERMISSIONS_R(0x4),
-        NO_PERMISSIONS_RW(0x5),
-        FOLDER_NOT_EMPTY(0x6),
-        ALREADY_EXISTS(0x7),
-        FOLDER_EXISTS(0x8),
-        UNSUPPORTED_OPERATION(0x9);
+    public final ErrorReason reason;
+    public final String details;
+    private ActionType action;
+    private EntryType entry = EntryType.FILE;
+    private String path;
 
-        public final int code;
+    public FilesystemException setPath(String path) {
+        this.path = path;
+        return this;
+    }
+    public FilesystemException setAction(ActionType action) {
+        if (action == null) action = ActionType.UNKNOWN;
 
-        private FSCode(int code) { this.code = code; }
+        this.action = action;
+        return this;
+    }
+    public FilesystemException setEntry(EntryType entry) {
+        if (entry == null) entry = EntryType.NONE;
+
+        this.entry = entry;
+        return this;
     }
 
-    public static final String[] MESSAGES = {
-        "How did we get here?",
-        "The file or folder '%s' doesn't exist or is inaccessible.",
-        "'%s' is not a file",
-        "'%s' is not a folder",
-        "No permissions to read '%s'",
-        "No permissions to write '%s'",
-        "Can't delete '%s', since it is a full folder.",
-        "'%s' already exists.",
-        "An unsupported operation was performed on the file '%s'."
-    };
-
-    public final String message, filename;
-    public final FSCode code;
-
-    public FilesystemException(String message, String filename, FSCode code) {
-        super(code + ": " + String.format(message, filename));
-        this.message = message;
-        this.code = code;
-        this.filename = filename;
+    public ActionType action() {
+        return action;
     }
-    public FilesystemException(String filename, FSCode code) {
-        super(code + ": " + String.format(MESSAGES[code.code], filename));
-        this.message = MESSAGES[code.code];
-        this.code = code;
-        this.filename = filename;
+    public String path() {
+        return path;
+    }
+    public EntryType entry() {
+        return entry;
     }
 
     public EngineException toEngineException() {
         var res = EngineException.ofError("IOError", getMessage());
-        Values.setMember(null, res.value, "code", code);
-        Values.setMember(null, res.value, "filename", filename.toString());
+
+        Values.setMember(null, res.value, "action", action.code);
+        Values.setMember(null, res.value, "reason", reason.code);
+        Values.setMember(null, res.value, "path", path);
+        Values.setMember(null, res.value, "entry", entry.name);
+        if (details != null) Values.setMember(null, res.value, "details", details);
+
         return res;
     }
+
+    @Override public String getMessage() {
+        var parts = new ArrayList<String>(10);
+
+        path = String.join(" ", parts).trim();
+        if (path.isEmpty()) path = null;
+        parts.clear();
+
+        parts.add(action == null ? "An action performed upon " : action.readable(reason.usePast));
+
+        if (entry == EntryType.FILE) parts.add("file");
+        if (entry == EntryType.FOLDER) parts.add("folder");
+
+        if (path != null) parts.add(path);
+
+        parts.add(reason.readable);
+
+        var msg = String.join(" ", parts);
+        if (details != null) msg += ": " + details;
+
+        return msg;
+    }
+
+    public FilesystemException(ErrorReason type, String details) {
+        super();
+        if (type == null) type = ErrorReason.UNKNOWN;
+
+        this.details = details;
+        this.reason = type;
+    }
+    public FilesystemException(ErrorReason type) {
+        this(type, null);
+    }
+    public FilesystemException() {
+        this(null);
+    }
+
 }

src/java/me/topchetoeu/jscript/utils/filesystem/HandleManager.java

@@ -0,0 +1,32 @@
+package me.topchetoeu.jscript.utils.filesystem;
+
+import java.util.HashSet;
+import java.util.Set;
+
+public class HandleManager {
+    private Set<File> files = new HashSet<>();
+
+    public File put(File val) {
+        var handle = new File() {
+            @Override public int read(byte[] buff) {
+                return val.read(buff);
+            }
+            @Override public void write(byte[] buff) {
+                val.write(buff);
+            }
+            @Override public long seek(long offset, int pos) {
+                return val.seek(offset, pos);
+            }
+            @Override public boolean close() {
+                return files.remove(this) && val.close();
+            }
+        };
+        files.add(handle);
+        return handle;
+    }
+    public void close() {
+        while (!files.isEmpty()) {
+            files.stream().findFirst().get().close();
+        }
+    }
+}

src/java/me/topchetoeu/jscript/utils/filesystem/LineReader.java

@@ -0,0 +1,16 @@
+package me.topchetoeu.jscript.utils.filesystem;
+
+import java.io.IOException;
+import java.util.Iterator;
+
+
+public interface LineReader {
+    String readLine() throws IOException;
+
+    public static LineReader ofIterator(Iterator<String> it) {
+        return () -> {
+            if (it.hasNext()) return it.next();
+            else return null;
+        };
+    }
+}

src/java/me/topchetoeu/jscript/utils/filesystem/LineWriter.java

@@ -0,0 +1,7 @@
+package me.topchetoeu.jscript.utils.filesystem;
+
+import java.io.IOException;
+
+public interface LineWriter {
+    void writeLine(String value) throws IOException;
+}

src/java/me/topchetoeu/jscript/utils/filesystem/ListFile.java

@@ -1,73 +0,0 @@
-package me.topchetoeu.jscript.utils.filesystem;
-
-import java.io.IOException;
-import java.util.Iterator;
-import java.util.stream.Stream;
-
-import me.topchetoeu.jscript.utils.filesystem.FilesystemException.FSCode;
-
-public class ListFile implements File {
-    private Iterator<String> it;
-    private String filename;
-    private byte[] currFile;
-    private long ptr = 0, start = 0, end = 0;
-
-    private void next() {
-        if (it != null && it.hasNext()) {
-            start = end;
-            currFile = (it.next() + "\n").getBytes();
-            end = start + currFile.length;
-        }
-        else {
-            it = null;
-            currFile = null;
-            end = -1;
-        }
-    }
-
-    @Override
-    public void close() {
-        it = null;
-        currFile = null;
-    }
-
-    @Override
-    public int read(byte[] buff) {
-        if (ptr < start) return 0;
-        if (it == null) return 0;
-
-        var i = 0;
-
-        while (i < buff.length) {
-            while (i + ptr >= end) {
-                next();
-                if (it == null) return 0;
-            }
-
-            int cpyN = Math.min(currFile.length, buff.length - i);
-            System.arraycopy(currFile, (int)(ptr + i - start), buff, i, cpyN);
-
-            i += cpyN;
-        }
-
-        ptr += i;
-        return i;
-    }
-
-    @Override
-    public long seek(long offset, int pos) {
-        if (pos == 2) throw new FilesystemException(filename, FSCode.UNSUPPORTED_OPERATION);
-        if (pos == 1) offset += ptr;
-        return ptr = offset;
-    }
-
-    @Override
-    public void write(byte[] buff) {
-        throw new FilesystemException(filename, FSCode.NO_PERMISSIONS_RW);
-    }
-
-    public ListFile(String filename, Stream<String> stream) throws IOException {
-        this.it = stream.iterator();
-        this.filename = filename;
-    }
-}

src/java/me/topchetoeu/jscript/utils/filesystem/MemoryFile.java

@@ -1,62 +1,35 @@
 package me.topchetoeu.jscript.utils.filesystem;
 
 import me.topchetoeu.jscript.common.Buffer;
-import me.topchetoeu.jscript.utils.filesystem.FilesystemException.FSCode;
 
-public class MemoryFile implements File {
+class MemoryFile extends BaseFile<Buffer> {
     private int ptr;
-    private Mode mode;
-    private Buffer data;
-    private String filename;
 
-    public Buffer data() { return data; }
-
-    @Override
-    public int read(byte[] buff) {
-        if (data == null || !mode.readable) throw new FilesystemException(filename, FSCode.NO_PERMISSIONS_R);
-        var res = data.read(ptr, buff);
+    @Override protected int onRead(byte[] buff) {
+        var res = handle().read(ptr, buff);
         ptr += res;
         return res;
     }
-    @Override
-    public void write(byte[] buff) {
-        if (data == null || !mode.writable) throw new FilesystemException(filename, FSCode.NO_PERMISSIONS_RW);
-
-        data.write(ptr, buff);
+    @Override protected void onWrite(byte[] buff) {
+        handle().write(ptr, buff);
         ptr += buff.length;
     }
-
-    @Override
-    public long seek(long offset, int pos) {
-        if (data == null || !mode.readable) throw new FilesystemException(filename, FSCode.NO_PERMISSIONS_R);
-
+    @Override protected long onSeek(long offset, int pos) {
         if (pos == 0) ptr = (int)offset;
         else if (pos == 1) ptr += (int)offset;
-        else if (pos == 2) ptr = data.length() - (int)offset;
+        else if (pos == 2) ptr = handle().length() - (int)offset;
 
         if (ptr < 0) ptr = 0;
-        if (ptr > data.length()) ptr = data.length();
+        if (ptr > handle().length()) ptr = handle().length();
 
         return pos;
     }
-
-    @Override
-    public void close() {
-        mode = Mode.NONE;
+    @Override protected boolean onClose() {
         ptr = 0;
+        return true;
     }
 
-    public MemoryFile(String filename, Buffer buff, Mode mode) {
-        this.filename = filename;
-        this.data = buff;
-        this.mode = mode;
+    public MemoryFile(Buffer buff, Mode mode) {
+        super(buff, mode);
     }
-
-    public static MemoryFile fromFileList(String filename, java.io.File[] list) {
-        var res = new StringBuilder();
-
-        for (var el : list) res.append(el.getName()).append('\n');
-
-        return new MemoryFile(filename, new Buffer(res.toString().getBytes()), Mode.READ);
-    }
-}
+}

src/java/me/topchetoeu/jscript/utils/filesystem/MemoryFilesystem.java

@@ -6,75 +6,79 @@ import java.util.HashSet;
 
 import me.topchetoeu.jscript.common.Buffer;
 import me.topchetoeu.jscript.common.Filename;
-import me.topchetoeu.jscript.utils.filesystem.FilesystemException.FSCode;
 
 public class MemoryFilesystem implements Filesystem {
     public final Mode mode;
     private HashMap<Path, Buffer> files = new HashMap<>();
     private HashSet<Path> folders = new HashSet<>();
+    private HandleManager handles = new HandleManager();
 
     private Path realPath(String path) {
         return Filename.normalize(path);
     }
 
-    @Override
-    public String normalize(String... path) {
+    @Override public String normalize(String... path) {
         return Paths.normalize(path);
     }
+    @Override public File open(String _path, Mode perms) {
+        try {
+            var path = realPath(_path);
+            var pcount = path.getNameCount();
 
-    @Override
-    public void create(String _path, EntryType type) {
-        var path = realPath(_path);
+            if (files.containsKey(path)) return handles.put(new MemoryFile(files.get(path), perms));
+            else if (folders.contains(path)) {
+                var res = new StringBuilder();
 
-        switch (type) {
-            case FILE:
-                if (!folders.contains(path.getParent())) throw new FilesystemException(path.toString(), FSCode.DOESNT_EXIST);
-                if (folders.contains(path) || files.containsKey(path)) throw new FilesystemException(path.toString(), FSCode.ALREADY_EXISTS);
-                if (folders.contains(path)) throw new FilesystemException(path.toString(), FSCode.ALREADY_EXISTS);
-                files.put(path, new Buffer());
-                break;
-            case FOLDER:
-                if (!folders.contains(path.getParent())) throw new FilesystemException(_path, FSCode.DOESNT_EXIST);
-                if (folders.contains(path) || files.containsKey(path)) throw new FilesystemException(path.toString(), FSCode.ALREADY_EXISTS);
-                folders.add(path);
-                break;
-            default:
-            case NONE:
-                if (!folders.remove(path) && files.remove(path) == null) throw new FilesystemException(path.toString(), FSCode.DOESNT_EXIST);
-        }
-    }
+                for (var folder : folders) {
+                    if (pcount + 1 != folder.getNameCount()) continue;
+                    if (!folder.startsWith(path)) continue;
+                    res.append(folder.toFile().getName()).append('\n');
+                }
 
-    @Override
-    public File open(String _path, Mode perms) {
-        var path = realPath(_path);
-        var pcount = path.getNameCount();
+                for (var file : files.keySet()) {
+                    if (pcount + 1 != file.getNameCount()) continue;
+                    if (!file.startsWith(path)) continue;
+                    res.append(file.toFile().getName()).append('\n');
+                }
 
-        if (files.containsKey(path)) return new MemoryFile(path.toString(), files.get(path), perms);
-        else if (folders.contains(path)) {
-            var res = new StringBuilder();
-            for (var folder : folders) {
-                if (pcount + 1 != folder.getNameCount()) continue;
-                if (!folder.startsWith(path)) continue;
-                res.append(folder.toFile().getName()).append('\n');
+                return handles.put(new MemoryFile(new Buffer(res.toString().getBytes()), perms.intersect(Mode.READ)));
             }
-            for (var file : files.keySet()) {
-                if (pcount + 1 != file.getNameCount()) continue;
-                if (!file.startsWith(path)) continue;
-                res.append(file.toFile().getName()).append('\n');
-            }
-            return new MemoryFile(path.toString(), new Buffer(res.toString().getBytes()), perms.intersect(Mode.READ));
+            else throw new FilesystemException(ErrorReason.DOESNT_EXIST);
         }
-        else throw new FilesystemException(path.toString(), FSCode.DOESNT_EXIST);
+        catch (FilesystemException e) { throw e.setPath(_path).setAction(ActionType.OPEN); }
     }
-
-    @Override
-    public FileStat stat(String _path) {
+    @Override public boolean create(String _path, EntryType type) {
+        try {
+            var path = realPath(_path);
+    
+            switch (type) {
+                case FILE:
+                    if (!folders.contains(path.getParent())) throw new FilesystemException(ErrorReason.NO_PARENT);
+                    if (folders.contains(path) || files.containsKey(path)) return false;
+                    files.put(path, new Buffer());
+                    return true;
+                case FOLDER:
+                    if (!folders.contains(path.getParent())) throw new FilesystemException(ErrorReason.NO_PARENT);
+                    if (folders.contains(path) || files.containsKey(path)) return false;
+                    folders.add(path);
+                    return true;
+                default:
+                case NONE:
+                    return folders.remove(path) || files.remove(path) != null;
+            }
+        }
+        catch (FilesystemException e) { throw e.setPath(_path).setAction(ActionType.CREATE); }
+    }
+    @Override public FileStat stat(String _path) {
         var path = realPath(_path);
 
         if (files.containsKey(path)) return new FileStat(mode, EntryType.FILE);
         else if (folders.contains(path)) return new FileStat(mode, EntryType.FOLDER);
         else return new FileStat(Mode.NONE, EntryType.NONE);
     }
+    @Override public void close() throws FilesystemException {
+        handles.close();
+    }
 
     public MemoryFilesystem put(String path, byte[] data) {
         var _path = realPath(path);

src/java/me/topchetoeu/jscript/utils/filesystem/Mode.java

@@ -3,6 +3,7 @@ package me.topchetoeu.jscript.utils.filesystem;
 public enum Mode {
     NONE("", false, false),
     READ("r", true, false),
+    WRITE("rw", false, true),
     READ_WRITE("rw", true, true);
 
     public final String name;
@@ -10,9 +11,7 @@ public enum Mode {
     public final boolean writable;
 
     public Mode intersect(Mode other) {
-        if (this == NONE || other == NONE) return NONE;
-        if (this == READ_WRITE && other == READ_WRITE) return READ_WRITE;
-        return READ;
+        return of(readable && other.readable, writable && other.writable);
     }
 
     private Mode(String mode, boolean r, boolean w) {
@@ -21,9 +20,20 @@ public enum Mode {
         this.writable = w;
     }
 
+    public static Mode of(boolean read, boolean write) {
+        if (read && write) return READ_WRITE;
+        if (read) return READ;
+        if (write) return WRITE;
+        return NONE;
+    }
+
     public static Mode parse(String mode) {
-        switch (mode) {
+        switch (mode.toLowerCase()) {
             case "r": return READ;
+            case "w": return WRITE;
+            case "r+":
+            case "w+":
+            case "wr":
             case "rw": return READ_WRITE;
             default: return NONE;
         }

src/java/me/topchetoeu/jscript/utils/filesystem/PhysicalFile.java

@@ -3,55 +3,33 @@ package me.topchetoeu.jscript.utils.filesystem;
 import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.io.RandomAccessFile;
+import java.nio.file.Path;
 
-import me.topchetoeu.jscript.utils.filesystem.FilesystemException.FSCode;
-
-public class PhysicalFile implements File {
-    private String filename;
-    private RandomAccessFile file;
-    private Mode mode;
-
-    @Override
-    public int read(byte[] buff) {
-        if (file == null || !mode.readable) throw new FilesystemException(filename, FSCode.NO_PERMISSIONS_R);
-        else try { return file.read(buff); }
-        catch (IOException e) { throw new FilesystemException(filename, FSCode.NO_PERMISSIONS_R); }
+public class PhysicalFile extends BaseFile<RandomAccessFile> {
+    @Override protected int onRead(byte[] buff) {
+        try { return handle().read(buff); }
+        catch (IOException e) { throw new FilesystemException(ErrorReason.NO_PERMISSION).setAction(ActionType.READ); }
     }
-    @Override
-    public void write(byte[] buff) {
-        if (file == null || !mode.writable) throw new FilesystemException(filename, FSCode.NO_PERMISSIONS_RW);
-        else try { file.write(buff); }
-        catch (IOException e) { throw new FilesystemException(filename, FSCode.NO_PERMISSIONS_RW); }
+    @Override protected void onWrite(byte[] buff) {
+        try { handle().write(buff); }
+        catch (IOException e) { throw new FilesystemException(ErrorReason.NO_PERMISSION).setAction(ActionType.WRITE); }
     }
-
-    @Override
-    public long seek(long offset, int pos) {
-        if (file == null || !mode.readable) throw new FilesystemException(filename, FSCode.NO_PERMISSIONS_R);
-
+    @Override protected long onSeek(long offset, int pos) {
         try {
-            if (pos == 1) offset += file.getFilePointer();
-            else if (pos == 2) offset += file.length();
-            file.seek(offset);
+            if (pos == 1) offset += handle().getFilePointer();
+            else if (pos == 2) offset += handle().length();
+            handle().seek(offset);
             return offset;
         }
-        catch (IOException e) { throw new FilesystemException(filename, FSCode.NO_PERMISSIONS_R); }
+        catch (IOException e) { throw new FilesystemException(ErrorReason.NO_PERMISSION).setAction(ActionType.SEEK); }
     }
-
-    @Override
-    public void close() {
-        if (file == null) return;
-        try { file.close(); }
+    @Override protected boolean onClose() {
+        try { handle().close(); }
         catch (IOException e) {} // SHUT
-        file = null;
-        mode = Mode.NONE;
+        return true;
     }
 
-    public PhysicalFile(String name, String path, Mode mode) throws FileNotFoundException {
-        this.filename = name;
-        this.mode = mode;
-
-        if (mode == Mode.NONE) file = null;
-        else try { file = new RandomAccessFile(path, mode.name); }
-        catch (FileNotFoundException e) { throw new FilesystemException(filename, FSCode.DOESNT_EXIST); }
+    public PhysicalFile(Path path, Mode mode) throws FileNotFoundException {
+        super(new RandomAccessFile(path.toFile(), mode.name), mode);
     }
 }

src/java/me/topchetoeu/jscript/utils/filesystem/PhysicalFilesystem.java

@@ -1,68 +1,69 @@
 package me.topchetoeu.jscript.utils.filesystem;
 
 import java.io.IOException;
+import java.nio.file.FileAlreadyExistsException;
 import java.nio.file.Files;
+import java.nio.file.NoSuchFileException;
 import java.nio.file.Path;
 
-import me.topchetoeu.jscript.utils.filesystem.FilesystemException.FSCode;
-
 public class PhysicalFilesystem implements Filesystem {
     public final String root;
+    private HandleManager handles = new HandleManager();
 
     private void checkMode(Path path, Mode mode) {
-        if (!path.startsWith(root)) throw new FilesystemException(path.toString(), FSCode.NO_PERMISSIONS_R);
+        if (!path.startsWith(root)) throw new FilesystemException(ErrorReason.NO_PERMISSION, "Tried to jailbreak the sandbox.");
 
-        if (mode.readable && !Files.isReadable(path)) throw new FilesystemException(path.toString(), FSCode.NO_PERMISSIONS_R);
-        if (mode.writable && !Files.isWritable(path)) throw new FilesystemException(path.toString(), FSCode.NO_PERMISSIONS_RW);
+        if (mode.readable && !Files.isReadable(path)) throw new FilesystemException(ErrorReason.NO_PERMISSION, "No read permissions");
+        if (mode.writable && !Files.isWritable(path)) throw new FilesystemException(ErrorReason.NO_PERMISSION, "No write permissions");
     }
 
     private Path realPath(String path) {
         return Path.of(Paths.chroot(root, path));
     }
 
-    @Override
-    public String normalize(String... paths) {
+    @Override public String normalize(String... paths) {
         return Paths.normalize(paths);
     }
-
-    @Override
-    public File open(String _path, Mode perms) {
-        _path = normalize(_path);
-        var path = realPath(_path);
-
-        checkMode(path, perms);
-
+    @Override public File open(String _path, Mode perms) {
         try {
-            if (Files.isDirectory(path)) return new ListFile(_path, Files.list(path).map((v -> v.getFileName().toString())));
-            else return new PhysicalFile(_path, path.toString(), perms);
+            var path = realPath(normalize(_path));
+            checkMode(path, perms);
+    
+            try {
+                if (Files.isDirectory(path)) return handles.put(File.ofIterator(
+                    Files.list(path).map(v -> v.getFileName().toString()).iterator()
+                ));
+                else return handles.put(new PhysicalFile(path, perms));
+            }
+            catch (IOException e) { throw new FilesystemException(ErrorReason.DOESNT_EXIST); }
         }
-        catch (IOException e) { throw new FilesystemException(path.toString(), FSCode.DOESNT_EXIST); }
+        catch (FilesystemException e) { throw e.setAction(ActionType.OPEN).setPath(_path); }
     }
-
-    @Override
-    public void create(String _path, EntryType type) {
-        var path = realPath(_path);
-
-        if (type == EntryType.NONE != Files.exists(path)) throw new FilesystemException(path.toString(), FSCode.ALREADY_EXISTS);
-
+    @Override public boolean create(String _path, EntryType type) {
         try {
-            switch (type) {
-                case FILE:
-                    Files.createFile(path);
-                    break;
-                case FOLDER:
-                    Files.createDirectories(path);
-                    break;
-                case NONE:
-                default:
-                    Files.delete(path);
-            } 
-        }
-        catch (IOException e) { throw new FilesystemException(path.toString(), FSCode.NO_PERMISSIONS_RW); }
-    }
+            var path = realPath(_path);
 
-    @Override
-    public FileStat stat(String _path) {
+            try {
+                switch (type) {
+                    case FILE:
+                        Files.createFile(path);
+                        break;
+                    case FOLDER:
+                        Files.createDirectories(path);
+                        break;
+                    case NONE:
+                    default:
+                        Files.delete(path);
+                } 
+            }
+            catch (FileAlreadyExistsException | NoSuchFileException e) { return false; }
+            catch (IOException e) { throw new FilesystemException(ErrorReason.NO_PARENT); }
+        }
+        catch (FilesystemException e) { throw e.setAction(ActionType.CREATE).setPath(_path); }
+
+        return true;
+    }
+    @Override public FileStat stat(String _path) {
         var path = realPath(_path);
 
         if (!Files.exists(path)) return new FileStat(Mode.NONE, EntryType.NONE);
@@ -81,6 +82,12 @@ public class PhysicalFilesystem implements Filesystem {
             Files.isDirectory(path) ? EntryType.FOLDER : EntryType.FILE
         );
     }
+    @Override public void close() throws FilesystemException {
+        try {
+            handles.close();
+        }
+        catch (FilesystemException e) { throw e.setAction(ActionType.CLOSE_FS); }
+    }
 
     public PhysicalFilesystem(String root) {
         this.root = Paths.normalize(Path.of(root).toAbsolutePath().toString());

src/java/me/topchetoeu/jscript/utils/filesystem/RootFilesystem.java

@@ -4,7 +4,7 @@ import java.util.HashMap;
 import java.util.Map;
 
 import me.topchetoeu.jscript.common.Filename;
-import me.topchetoeu.jscript.utils.filesystem.FilesystemException.FSCode;
+import me.topchetoeu.jscript.utils.permissions.Matcher;
 import me.topchetoeu.jscript.utils.permissions.PermissionsProvider;
 
 public class RootFilesystem implements Filesystem {
@@ -12,15 +12,29 @@ public class RootFilesystem implements Filesystem {
     public final PermissionsProvider perms;
 
     private boolean canRead(String _path) {
-        return perms.hasPermission("jscript.file.read:" + _path, '/');
+        return perms.hasPermission("jscript.file.read:" + _path, Matcher.fileWildcard());
     }
     private boolean canWrite(String _path) {
-        return perms.hasPermission("jscript.file.write:" + _path, '/');
+        return perms.hasPermission("jscript.file.write:" + _path, Matcher.fileWildcard());
     }
 
     private void modeAllowed(String _path, Mode mode) throws FilesystemException {
-        if (mode.readable && perms != null && !canRead(_path)) throw new FilesystemException(_path, FSCode.NO_PERMISSIONS_R);
-        if (mode.writable && perms != null && !canWrite(_path)) throw new FilesystemException(_path, FSCode.NO_PERMISSIONS_RW);
+        if (mode.readable && perms != null && !canRead(_path)) {
+            throw new FilesystemException(ErrorReason.NO_PERMISSION, "No read permissions").setPath(_path);
+        }
+        if (mode.writable && perms != null && !canWrite(_path)) {
+            throw new FilesystemException(ErrorReason.NO_PERMISSION, "No wtrite permissions").setPath(_path);
+        }
+    }
+
+    private Filesystem getProtocol(Filename filename) {
+        var protocol = protocols.get(filename.protocol);
+
+        if (protocol == null) {
+            throw new FilesystemException(ErrorReason.DOESNT_EXIST, "The protocol '" + filename.protocol + "' doesn't exist.");
+        }
+
+        return protocol;
     }
 
     @Override public String normalize(String... paths) {
@@ -36,30 +50,43 @@ public class RootFilesystem implements Filesystem {
         }
     }
     @Override public File open(String path, Mode perms) throws FilesystemException {
-        var filename = Filename.parse(path);
-        var protocol = protocols.get(filename.protocol);
-        if (protocol == null) throw new FilesystemException(filename.toString(), FSCode.DOESNT_EXIST);
-        modeAllowed(filename.toString(), perms);
+        try {
+            var filename = Filename.parse(path);
+            var protocol = getProtocol(filename);
 
-        try { return protocol.open(filename.path, perms); }
-        catch (FilesystemException e) { throw new FilesystemException(filename.toString(), e.code); }
+            modeAllowed(filename.toString(), perms);
+            return protocol.open(filename.path, perms);
+        }
+        catch (FilesystemException e) { throw e.setPath(path).setAction(ActionType.OPEN); }
     }
-    @Override public void create(String path, EntryType type) throws FilesystemException {
-        var filename = Filename.parse(path);
-        var protocol = protocols.get(filename.protocol);
-        if (protocol == null) throw new FilesystemException(filename.toString(), FSCode.DOESNT_EXIST);
-        modeAllowed(filename.toString(), Mode.READ_WRITE);
+    @Override public boolean create(String path, EntryType type) throws FilesystemException {
+        try {
+            var filename = Filename.parse(path);
+            var protocol = getProtocol(filename);
 
-        try { protocol.create(filename.path, type); }
-        catch (FilesystemException e) { throw new FilesystemException(filename.toString(), e.code); }
+            modeAllowed(filename.toString(), Mode.WRITE);
+            return protocol.create(filename.path, type);
+        }
+        catch (FilesystemException e) { throw e.setPath(path).setAction(ActionType.CREATE); }
     }
     @Override public FileStat stat(String path) throws FilesystemException {
-        var filename = Filename.parse(path);
-        var protocol = protocols.get(filename.protocol);
-        if (protocol == null) throw new FilesystemException(filename.toString(), FSCode.DOESNT_EXIST);
+        try {
+            var filename = Filename.parse(path);
+            var protocol = getProtocol(filename);
 
-        try { return protocol.stat(filename.path); }
-        catch (FilesystemException e) { throw new FilesystemException(filename.toString(), e.code); }
+            return protocol.stat(filename.path);
+        }
+        catch (FilesystemException e) { throw e.setPath(path).setAction(ActionType.STAT); }
+    }
+    @Override public void close() throws FilesystemException {
+        try {
+            for (var protocol : protocols.values()) {
+                protocol.close();
+            }
+
+            protocols.clear();
+        }
+        catch (FilesystemException e) { throw e.setAction(ActionType.CLOSE_FS); }
     }
 
     public RootFilesystem(PermissionsProvider perms) {

src/java/me/topchetoeu/jscript/utils/filesystem/STDFilesystem.java

@@ -0,0 +1,42 @@
+package me.topchetoeu.jscript.utils.filesystem;
+
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.util.HashMap;
+
+public class STDFilesystem implements Filesystem {
+    private final HashMap<String, File> handles = new HashMap<>();
+
+    @Override
+    public String normalize(String... path) {
+        var res = Paths.normalize(path);
+        while (res.startsWith("/")) res = res.substring(1);
+        return res;
+    }
+
+    @Override public File open(String path, Mode mode) {
+        path = normalize(path);
+        if (handles.containsKey(path)) return handles.get(path);
+        else throw new FilesystemException(ErrorReason.DOESNT_EXIST).setAction(ActionType.OPEN).setPath(path);
+    }
+    @Override public FileStat stat(String path) {
+        path = normalize(path);
+        if (handles.containsKey(path)) return new FileStat(Mode.READ_WRITE, EntryType.FILE);
+        else return new FileStat(Mode.NONE, EntryType.NONE);
+    }
+    @Override public void close() {
+        handles.clear();
+    }
+
+    public STDFilesystem add(String name, File handle) {
+        this.handles.put(name, handle);
+        return this;
+    }
+
+    public static STDFilesystem ofStd(InputStream in, OutputStream out, OutputStream err) {
+        return new STDFilesystem()
+            .add("in", File.ofStream(in))
+            .add("out", File.ofStream(out))
+            .add("err", File.ofStream(err));
+    }
+}

src/java/me/topchetoeu/jscript/utils/permissions/Matcher.java

@@ -0,0 +1,69 @@
+package me.topchetoeu.jscript.utils.permissions;
+
+import java.util.LinkedList;
+
+public interface Matcher {
+    static class State {
+        public final int predI, trgI, wildcardI;
+        public final boolean wildcard;
+
+        @Override
+        public String toString() {
+            return String.format("State [pr=%s;trg=%s;wildN=%s;wild=%s]", predI, trgI, wildcardI, wildcard);
+        }
+
+        public State(int predicateI, int targetI, int wildcardI, boolean wildcard) {
+            this.predI = predicateI;
+            this.trgI = targetI;
+            this.wildcardI = wildcardI;
+            this.wildcard = wildcard;
+        }
+    }
+
+    boolean match(String predicate, String value);
+
+    public static Matcher fileWildcard() {
+        return (predicate, value) -> execWildcard(predicate, value, '/');
+    }
+    public static Matcher namespaceWildcard() {
+        return (predicate, value) -> execWildcard(predicate, value, '.');
+    }
+    public static Matcher wildcard() {
+        return (predicate, value) -> execWildcard(predicate, value, '\0');
+    }
+
+    public static boolean execWildcard(String predicate, String target, char delim) {
+        if (predicate.equals("")) return target.equals("");
+
+        var queue = new LinkedList<State>();
+        queue.push(new State(0, 0, 0, false));
+
+        while (!queue.isEmpty()) {
+            var state = queue.poll();
+            var predEnd = state.predI >= predicate.length();
+
+            if (state.trgI >= target.length()) return predEnd;
+            var predC = predEnd ? 0 : predicate.charAt(state.predI);
+            var trgC = target.charAt(state.trgI);
+
+            if (state.wildcard) {
+                if (state.wildcardI == 2 || trgC != delim) {
+                    queue.add(new State(state.predI, state.trgI + 1, state.wildcardI, true));
+                }
+                queue.add(new State(state.predI, state.trgI, 0, false));
+            }
+            else if (predC == '*') {
+                queue.add(new State(state.predI + 1, state.trgI, state.wildcardI + 1, false));
+            }
+            else if (state.wildcardI > 0) {
+                if (state.wildcardI > 2) throw new IllegalArgumentException("Too many sequential stars.");
+                queue.add(new State(state.predI, state.trgI, state.wildcardI, true));
+            }
+            else if (!predEnd && (predC == '?' || predC == trgC)) {
+                queue.add(new State(state.predI + 1, state.trgI + 1, 0, false));
+            }
+        }
+
+        return false;
+    }
+}

src/java/me/topchetoeu/jscript/utils/permissions/Permission.java

@@ -1,124 +1,19 @@
 package me.topchetoeu.jscript.utils.permissions;
 
-import java.util.LinkedList;
 
 public class Permission {
-    private static class State {
-        public final int predI, trgI, wildcardI;
-        public final boolean wildcard;
-
-        @Override
-        public String toString() {
-            return String.format("State [pr=%s;trg=%s;wildN=%s;wild=%s]", predI, trgI, wildcardI, wildcard);
-        }
-
-        public State(int predicateI, int targetI, int wildcardI, boolean wildcard) {
-            this.predI = predicateI;
-            this.trgI = targetI;
-            this.wildcardI = wildcardI;
-            this.wildcard = wildcard;
-        }
-    }
-
     public final String namespace;
-    public final String value;
+    public final Matcher matcher;
 
-    public boolean match(Permission perm) {
-        if (!Permission.match(namespace, perm.namespace, '.')) return false;
-        if (value == null || perm.value == null) return true;
-        return Permission.match(value, perm.value);
-    }
-    public boolean match(Permission perm, char delim) {
-        if (!Permission.match(namespace, perm.namespace, '.')) return false;
-        if (value == null || perm.value == null) return true;
-        return Permission.match(value, perm.value, delim);
+    @Override public String toString() {
+        return namespace;
     }
 
-    public boolean match(String perm) {
-        return match(new Permission(perm));
+    public Permission(String namespace, Matcher matcher) {
+        this.namespace = namespace;
+        this.matcher = matcher;
     }
-    public boolean match(String perm, char delim) {
-        return match(new Permission(perm), delim);
-    }
-
-    @Override
-    public String toString() {
-        if (value != null) return namespace + ":" + value;
-        else return namespace;
-    }
-
     public Permission(String raw) {
-        var i = raw.indexOf(':');
-
-        if (i > 0) {
-            value = raw.substring(i + 1);
-            namespace = raw.substring(0, i);
-        }
-        else {
-            value = null;
-            namespace = raw;
-        }
-    }
-
-    public static boolean match(String predicate, String target, char delim) {
-        if (predicate.equals("")) return target.equals("");
-
-        var queue = new LinkedList<State>();
-        queue.push(new State(0, 0, 0, false));
-
-        while (!queue.isEmpty()) {
-            var state = queue.poll();
-            var predEnd = state.predI >= predicate.length();
-
-            if (state.trgI >= target.length()) return predEnd;
-            var predC = predEnd ? 0 : predicate.charAt(state.predI);
-            var trgC = target.charAt(state.trgI);
-
-            if (state.wildcard) {
-                if (state.wildcardI == 2 || trgC != delim) {
-                    queue.add(new State(state.predI, state.trgI + 1, state.wildcardI, true));
-                }
-                queue.add(new State(state.predI, state.trgI, 0, false));
-            }
-            else if (predC == '*') {
-                queue.add(new State(state.predI + 1, state.trgI, state.wildcardI + 1, false));
-            }
-            else if (state.wildcardI > 0) {
-                if (state.wildcardI > 2) throw new IllegalArgumentException("Too many sequential stars.");
-                queue.add(new State(state.predI, state.trgI, state.wildcardI, true));
-            }
-            else if (!predEnd && (predC == '?' || predC == trgC)) {
-                queue.add(new State(state.predI + 1, state.trgI + 1, 0, false));
-            }
-        }
-
-        return false;
-    }
-    public static boolean match(String predicate, String target) {
-        if (predicate.equals("")) return target.equals("");
-
-        var queue = new LinkedList<State>();
-        queue.push(new State(0, 0, 0, false));
-
-        while (!queue.isEmpty()) {
-            var state = queue.poll();
-
-            if (state.predI >= predicate.length() || state.trgI >= target.length()) {
-                return state.predI >= predicate.length() && state.trgI >= target.length();
-            }
-
-            var predC = predicate.charAt(state.predI);
-            var trgC = target.charAt(state.trgI);
-
-            if (predC == '*') {
-                queue.add(new State(state.predI, state.trgI + 1, state.wildcardI, true));
-                queue.add(new State(state.predI + 1, state.trgI, 0, false));
-            }
-            else if (predC == '?' || predC == trgC) {
-                queue.add(new State(state.predI + 1, state.trgI + 1, 0, false));
-            }
-        }
-
-        return false;
+        this(raw, null);
     }
 }

src/java/me/topchetoeu/jscript/utils/permissions/PermissionPredicate.java

@@ -0,0 +1,44 @@
+package me.topchetoeu.jscript.utils.permissions;
+
+public class PermissionPredicate {
+    public final String namespace;
+    public final String value;
+    public final boolean denies;
+
+    public boolean match(Permission permission, String value) {
+        if (!match(permission)) return false;
+        if (this.value == null || value == null) return true;
+        if (permission.matcher == null) return true;
+        else return permission.matcher.match(this.value, value);
+    }
+    public boolean match(Permission permission) {
+        return Matcher.namespaceWildcard().match(namespace, permission.namespace);
+    }
+
+    @Override
+    public String toString() {
+        if (value != null) return namespace + ":" + value;
+        else return namespace;
+    }
+
+    public PermissionPredicate(String raw) {
+        raw = raw.trim();
+
+        if (raw.startsWith("!")) {
+            denies = true;
+            raw = raw.substring(1).trim();
+        }
+        else denies = false;
+
+        var i = raw.indexOf(':');
+
+        if (i > 0) {
+            value = raw.substring(i + 1);
+            namespace = raw.substring(0, i);
+        }
+        else {
+            value = null;
+            namespace = raw;
+        }
+    }
+}

src/java/me/topchetoeu/jscript/utils/permissions/PermissionsManager.java

@@ -1,34 +1,59 @@
 package me.topchetoeu.jscript.utils.permissions;
 
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
 import java.util.ArrayList;
 
 public class PermissionsManager implements PermissionsProvider {
-    public static final PermissionsProvider ALL_PERMS = new PermissionsManager().add(new Permission("**"));
+    public final ArrayList<PermissionPredicate> predicates = new ArrayList<>();
 
-    public final ArrayList<Permission> allowed = new ArrayList<>();
-    public final ArrayList<Permission> denied = new ArrayList<>();
-
-    public PermissionsProvider add(Permission perm) {
-        allowed.add(perm);
+    public PermissionsProvider add(PermissionPredicate perm) {
+        predicates.add(perm);
         return this;
     }
     public PermissionsProvider add(String perm) {
-        allowed.add(new Permission(perm));
+        predicates.add(new PermissionPredicate(perm));
         return this;
     }
 
-    @Override
-    public boolean hasPermission(Permission perm, char delim) {
-        for (var el : denied) if (el.match(perm, delim)) return false;
-        for (var el : allowed) if (el.match(perm, delim)) return true;
+    @Override public boolean hasPermission(Permission perm, String value) {
+        for (var el : predicates) {
+            if (el.match(perm, value)) {
+                if (el.denies) return false;
+                else return true;
+            }
+        }
 
         return false;
     }
-    @Override
-    public boolean hasPermission(Permission perm) {
-        for (var el : denied) if (el.match(perm)) return false;
-        for (var el : allowed) if (el.match(perm)) return true;
+    @Override public boolean hasPermission(Permission perm) {
+        for (var el : predicates) {
+            if (el.match(perm)) {
+                if (el.denies) return false;
+                else return true;
+            }
+        }
 
         return false;
     }
+
+    public PermissionsProvider addFromStream(InputStream stream) throws IOException {
+        var reader = new BufferedReader(new InputStreamReader(stream));
+        String line;
+
+        while ((line = reader.readLine()) != null) {
+            var i = line.indexOf('#');
+            if (i >= 0) line = line.substring(0, i);
+
+            line = line.trim();
+
+            if (line.isEmpty()) continue;
+
+            add(line);
+        }
+
+        return this;
+    }
 }

src/java/me/topchetoeu/jscript/utils/permissions/PermissionsProvider.java

@@ -5,27 +5,25 @@ import me.topchetoeu.jscript.core.engine.values.Symbol;
 
 public interface PermissionsProvider {
     public static final Symbol ENV_KEY = new Symbol("Environment.perms");
+    public static final PermissionsProvider ALL_PERMS = (perm, value) -> true;
 
-    boolean hasPermission(Permission perm, char delim);
-    boolean hasPermission(Permission perm);
+    boolean hasPermission(Permission perm, String value);
 
-    default boolean hasPermission(String perm, char delim) {
-        return hasPermission(new Permission(perm), delim);
+    default boolean hasPermission(Permission perm) {
+        return hasPermission(perm, null);
     }
-    default boolean hasPermission(String perm) {
-        return hasPermission(new Permission(perm));
+
+    default boolean hasPermission(String perm, String value, Matcher matcher) {
+        return hasPermission(new Permission(perm, matcher), value);
+    }
+    default boolean hasPermission(String perm, Matcher matcher) {
+        return hasPermission(new Permission(perm, matcher));
     }
 
     public static PermissionsProvider get(Extensions exts) {
-        return new PermissionsProvider() {
-            @Override public boolean hasPermission(Permission perm) {
-                if (exts.hasNotNull(ENV_KEY)) return ((PermissionsProvider)exts.get(ENV_KEY)).hasPermission(perm);
-                else return true;
-            }
-            @Override public boolean hasPermission(Permission perm, char delim) {
-                if (exts.hasNotNull(ENV_KEY)) return ((PermissionsProvider)exts.get(ENV_KEY)).hasPermission(perm, delim);
-                else return true;
-            }
+        return (perm, value) -> {
+            if (exts.hasNotNull(ENV_KEY)) return ((PermissionsProvider)exts.get(ENV_KEY)).hasPermission(perm);
+            else return true;
         };
     }
 }