michael@0: /* Very basic JNI support for JS
michael@0:  *
michael@0:  * Example Usage:
michael@0:  *   let jni = new JNI();
michael@0:  *   cls = jni.findClass("org/mozilla/gecko/GeckoAppShell");
michael@0:  *   method = jni.getStaticMethodID(cls, "getPreferredIconSize", "(I)I");
michael@0:  *
michael@0:  *   let val = jni.callStaticIntMethod(cls, method, 3);
michael@0:  *   // close the jni library when you are done
michael@0:  *   jni.close();
michael@0:  *
michael@0:  * Note: the getters in this file are deleted and replaced with static
michael@0:  * values once computed, as in, for example
michael@0:  * http://code.activestate.com/recipes/577310-using-a-getter-for-a-one-time-calculation-of-a-jav/
michael@0:  */
michael@0: this.EXPORTED_SYMBOLS = ["JNI"];
michael@0: 
michael@0: Components.utils.import("resource://gre/modules/ctypes.jsm")
michael@0: Components.utils.import("resource://gre/modules/Services.jsm")
michael@0: 
michael@0: this.JNI = function JNI() { }
michael@0: 
michael@0: JNI.prototype = {
michael@0:   get lib() {
michael@0:     delete this.lib;
michael@0:     return this.lib = ctypes.open("libxul.so");
michael@0:   },
michael@0: 
michael@0:   getType: function(aType) {
michael@0:     switch(aType) {
michael@0:       case "B": return ctypes.char;
michael@0:       case "C": return ctypes.char;
michael@0:       case "D": return ctypes.double;
michael@0:       case "F": return ctypes.float;
michael@0:       case "I": return ctypes.int32_t;
michael@0:       case "J": return ctypes.int64_t;
michael@0:       case "S": return ctypes.int16_t;
michael@0:       case "V": return ctypes.void_t;
michael@0:       case "Z": return ctypes.bool;
michael@0:       default: return this.types.jobject
michael@0:     }
michael@0:   },
michael@0: 
michael@0:   getArgs: function(aMethod, aArgs) {
michael@0:     if (aArgs.length != aMethod.parameters.length)
michael@0:       throw ("Incorrect number of arguments passed to " + aMethod.name);
michael@0: 
michael@0:     // Convert arguments to an array of jvalue objects
michael@0:     let modifiedArgs = new ctypes.ArrayType(this.types.jvalue, aMethod.parameters.length)();
michael@0:     for (let i = 0; i < aMethod.parameters.length; i++) {
michael@0:       let parameter = aMethod.parameters[i];
michael@0:       let arg = new this.types.jvalue();
michael@0: 
michael@0:       if (aArgs[i] instanceof Array || parameter[0] == "[")
michael@0:         throw "No support for array arguments yet";
michael@0:       else
michael@0:         ctypes.cast(arg, this.getType(parameter)).value = aArgs[i];
michael@0: 
michael@0:       modifiedArgs[i] = arg;
michael@0:     }
michael@0: 
michael@0:     return modifiedArgs;
michael@0:   },
michael@0: 
michael@0:   types: {
michael@0:     jobject: ctypes.StructType("_jobject").ptr,
michael@0:     jclass: ctypes.StructType("_jobject").ptr,
michael@0:     jmethodID: ctypes.StructType("jmethodID").ptr,
michael@0:     jvalue: ctypes.double
michael@0:   },
michael@0: 
michael@0:   get _findClass() {
michael@0:     delete this._findClass;
michael@0:     return this._findClass = this.lib.declare("jsjni_FindClass",
michael@0:                                               ctypes.default_abi,
michael@0:                                               this.types.jclass,
michael@0:                                               ctypes.char.ptr);
michael@0:   },
michael@0: 
michael@0:   findClass: function(name) {
michael@0:     let ret = this._findClass(name);
michael@0:     if (this.exceptionCheck())
michael@0:        throw("Can't find class " + name);
michael@0:     return ret;
michael@0:   },
michael@0: 
michael@0:   get _getStaticMethodID() {
michael@0:     delete this._getStaticMethodID;
michael@0:     return this._getStaticMethodID = this.lib.declare("jsjni_GetStaticMethodID",
michael@0:                                                       ctypes.default_abi,
michael@0:                                                       this.types.jmethodID,
michael@0:                                                       this.types.jclass, // class
michael@0:                                                       ctypes.char.ptr,   // method name
michael@0:                                                       ctypes.char.ptr);  // signature
michael@0:   },
michael@0: 
michael@0:   getStaticMethodID: function(aClass, aName, aSignature) {
michael@0:     let ret = this._getStaticMethodID(aClass, aName, aSignature);
michael@0:     if (this.exceptionCheck())
michael@0:        throw("Can't find method " + aName);
michael@0:     return new jMethod(aName, ret, aSignature);
michael@0:   },
michael@0: 
michael@0:   get _exceptionCheck() {
michael@0:     delete this._exceptionCheck;
michael@0:     return this._exceptionCheck = this.lib.declare("jsjni_ExceptionCheck",
michael@0:                                                    ctypes.default_abi,
michael@0:                                                    ctypes.bool);
michael@0:   },
michael@0: 
michael@0:   exceptionCheck: function() {
michael@0:     return this._exceptionCheck();
michael@0:   },
michael@0: 
michael@0:   get _callStaticVoidMethod() {
michael@0:     delete this._callStaticVoidMethod;
michael@0:     return this._callStaticVoidMethod = this.lib.declare("jsjni_CallStaticVoidMethodA",
michael@0:                                                    ctypes.default_abi,
michael@0:                                                    ctypes.void_t,
michael@0:                                                    this.types.jclass,
michael@0:                                                    this.types.jmethodID,
michael@0:                                                    this.types.jvalue.ptr);
michael@0:   },
michael@0: 
michael@0:   callStaticVoidMethod: function(aClass, aMethod) {
michael@0:     let args = Array.prototype.slice.apply(arguments, [2]);
michael@0:     this._callStaticVoidMethod(aClass, aMethod.methodId, this.getArgs(aMethod, args));
michael@0:     if (this.exceptionCheck())
michael@0:        throw("Error calling static void method");
michael@0:   },
michael@0: 
michael@0:   get _callStaticIntMethod() {
michael@0:     delete this._callStaticIntMethod;
michael@0:     return this._callStaticIntMethod = this.lib.declare("jsjni_CallStaticIntMethodA",
michael@0:                                                    ctypes.default_abi,
michael@0:                                                    ctypes.int,
michael@0:                                                    this.types.jclass,
michael@0:                                                    this.types.jmethodID,
michael@0:                                                    this.types.jvalue.ptr);
michael@0:   },
michael@0: 
michael@0:   callStaticIntMethod: function(aClass, aMethod) {
michael@0:     let args = Array.prototype.slice.apply(arguments, [2]);
michael@0:     let ret = this._callStaticIntMethod(aClass, aMethod.methodId, this.getArgs(aMethod, args));
michael@0:     if (this.exceptionCheck())
michael@0:        throw("Error calling static int method");
michael@0:     return ret;
michael@0:   },
michael@0: 
michael@0:   close: function() {
michael@0:     this.lib.close();
michael@0:   },
michael@0: }
michael@0: 
michael@0: function jMethod(name, jMethodId, signature) {
michael@0:   this.name = name;
michael@0:   this.methodId = jMethodId;
michael@0:   this.signature = signature;
michael@0: }
michael@0: 
michael@0: jMethod.prototype = {
michael@0:   parameters: [],
michael@0:   returnType: null,
michael@0:   _signature: "",
michael@0: 
michael@0:   // this just splits up the return value from the parameters
michael@0:   signatureRegExp: /^\(([^\)]*)\)(.*)$/,
michael@0: 
michael@0:   // This splits up the actual parameters
michael@0:   parameterRegExp: /(\[*)(B|C|D|F|I|J|S|V|Z|L[^;]*;)/y,
michael@0: 
michael@0:   parseSignature: function(aSignature) {
michael@0:     let [, parameters, returnType] = this.signatureRegExp.exec(aSignature);
michael@0: 
michael@0:     // parse the parameters that should be passed to this method
michael@0:     if (parameters) {
michael@0:       let parameter = this.parameterRegExp.exec(parameters);
michael@0:       while (parameter) {
michael@0:         this.parameters.push(parameter[0]);
michael@0:         parameter = this.parameterRegExp.exec(parameters);
michael@0:       }
michael@0:     } else {
michael@0:       this.parameters = [];
michael@0:     }
michael@0: 
michael@0:     // parse the return type
michael@0:     this.returnType = returnType;
michael@0:   },
michael@0: 
michael@0:   _signature: "",
michael@0:   get signature() { return this._signature; },
michael@0:   set signature(val) {
michael@0:     this.parameters = [];
michael@0:     this.returnType = null;
michael@0:     this.parseSignature(val);
michael@0:   }
michael@0: }