some restructuring, added first version of the mozjs plugin

git-svn-id: file:///var/local/svn/basicwriter@78 daaaf23c-2e50-4459-9457-1e69db5a47bf

2 files changed, 294 insertions, 0 deletions

diff --git a/src/plugins/mozjs/MozJsScriptEngine.cpp b/src/plugins/mozjs/MozJsScriptEngine.cpp
new file mode 100644
index 0000000..b7ff002
--- /dev/null
+++ b/src/plugins/mozjs/MozJsScriptEngine.cpp
@@ -0,0 +1,218 @@
+/*
+    Ousía
+    Copyright (C) 2014, 2015  Benjamin Paaßen, Andreas Stöckel
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "MozJsScriptEngine.hpp"
+
+namespace ousia {
+namespace script {
+
+/*
+ * Some important links to the SpiderMonkey (mozjs) documentation:
+ *
+ * Documentation overview:
+ * https://developer.mozilla.org/en-US/docs/Mozilla/Projects/SpiderMonkey/
+ *
+ * User Guide:
+ * https://developer.mozilla.org/en-US/docs/Mozilla/Projects/SpiderMonkey/JSAPI_User_Guide
+ *
+ * API Reference:
+ * https://developer.mozilla.org/en-US/docs/Mozilla/Projects/SpiderMonkey/JSAPI_reference
+ */
+
+/* Constants */
+
+static const uint32_t MOZJS_RT_MEMSIZE = 64L * 1024L * 1024L;
+static const uint32_t MOZJS_CTX_STACK_CHUNK_SIZE = 8192;
+
+/* Class MozJsScriptEngineScope */
+
+/**
+ * The class of the global object.
+ */
+static JSClass globalClass = {
+    "global",              JSCLASS_GLOBAL_FLAGS, JS_PropertyStub,
+    JS_DeletePropertyStub, JS_PropertyStub,      JS_StrictPropertyStub,
+    JS_EnumerateStub,      JS_ResolveStub,       JS_ConvertStub,
+    nullptr,               nullptr,              nullptr,
+    nullptr,               nullptr};
+
+MozJsScriptEngineScope::MozJsScriptEngineScope(JSRuntime *rt) : rt(rt)
+{
+	// Create the execution context
+	cx = JS_NewContext(rt, MOZJS_CTX_STACK_CHUNK_SIZE);
+	if (!cx) {
+		throw ScriptEngineException{"MozJs JS_NewContext failed"};
+	}
+
+	// Start a context request
+	JS_BeginRequest(cx);
+
+	// Set some context options
+	JS_SetOptions(cx, JS_GetOptions(cx) | JSOPTION_EXTRA_WARNINGS |
+	                      JSOPTION_VAROBJFIX | JSOPTION_DONT_REPORT_UNCAUGHT);
+
+	// Create the rooted global object
+	global =
+	    new JS::RootedObject(cx, JS_NewGlobalObject(cx, &globalClass, nullptr));
+
+	// Enter a compartment (heap memory region) surrounding the global object
+	oldCompartment = JS_EnterCompartment(cx, *global);
+
+	// Populate the global object with the standard classes
+	if (!JS_InitStandardClasses(cx, *global)) {
+		throw ScriptEngineException{"MozJS JS_InitStandardClasses failed"};
+	}
+}
+
+MozJsScriptEngineScope::~MozJsScriptEngineScope()
+{
+	// Leave the compartment
+	JS_LeaveCompartment(cx, oldCompartment);
+
+	// Free the reference to the local object
+	delete global;
+
+	// End the request
+	JS_EndRequest(cx);
+
+	// Destroy the execution context
+	JS_DestroyContext(cx);
+}
+
+Variant MozJsScriptEngineScope::toVariant(const JS::Value &val)
+{
+	if (val.isBoolean()) {
+		return Variant{val.toBoolean()};
+	}
+	if (val.isInt32()) {
+		return Variant{(int64_t)val.toInt32()};
+	}
+	if (val.isDouble()) {
+		return Variant{val.toDouble()};
+	}
+	if (val.isString()) {
+		// TODO: Remove the need for using "c_str"!
+		return Variant{toString(val.toString()).c_str()};
+	}
+	return Variant::Null;
+}
+
+void MozJsScriptEngineScope::handleErr(bool ok)
+{
+	if (!ok && JS_IsExceptionPending(cx)) {
+		JS::Value exception;
+		if (JS_GetPendingException(cx, &exception)) {
+			// Fetch messgage string, line and column
+			JS::Value msg, line, col;
+			JS_GetPendingException(cx, &exception);
+			JS_GetProperty(cx, JSVAL_TO_OBJECT(exception), "message", &msg);
+			JS_GetProperty(cx, JSVAL_TO_OBJECT(exception), "lineNumber", &line);
+			JS_GetProperty(cx, JSVAL_TO_OBJECT(exception), "columnNumber",
+			               &col);
+
+			// Clear the exception
+			JS_ClearPendingException(cx);
+
+			// Produce a nice error message in case the caught exception is of
+			// the "Error" class
+			if (msg.isString() && line.isInt32() && col.isInt32()) {
+				// Throw a script engine exception with the corresponding line,
+				// column and string
+				throw ScriptEngineException{line.toInt32(), col.toInt32(),
+				                            toString(msg)};
+			}
+
+			// Otherwise simply convert the exception to a string
+			throw ScriptEngineException{toString(exception)};
+		}
+	}
+}
+
+std::string MozJsScriptEngineScope::toString(const JS::Value &val)
+{
+	// If the given value already is a Javascript string, return it directly.
+	if (val.isString()) {
+		return toString(val.toString());
+	}
+
+	// The given value is not really a string, so convert it to one first
+	JSString *str = JS_ValueToString(cx, val);
+	if (!str) {
+		throw ScriptEngineException{"Cannot convert value to string"};
+	}
+
+	return toString(str);
+}
+
+std::string MozJsScriptEngineScope::toString(JSString *str)
+{
+	// Encode the string
+	char *buf = JS_EncodeStringToUTF8(cx, str);
+	if (!buf) {
+		throw ScriptEngineException{"JS_EncodeStringToUTF8 failed"};
+	}
+
+	// Copy the string into a std::string, free the original buffer and return
+	std::string res{buf};
+	JS_free(cx, buf);
+	return res;
+}
+
+Variant MozJsScriptEngineScope::doRun(const std::string &code)
+{
+	JS::Value rval;
+	handleErr(JS_EvaluateScript(cx, *global, code.c_str(), code.length(), "", 0,
+	                            &rval));
+	return toVariant(rval);
+}
+
+void MozJsScriptEngineScope::doSetVariable(const std::string &name,
+                                           const Variant &val, bool constant)
+{
+	// TODO
+}
+
+Variant MozJsScriptEngineScope::doGetVariable(const std::string &name)
+{
+	// TODO
+	return Variant::Null;
+}
+
+/* Class MozJsScriptEngine */
+
+MozJsScriptEngine::MozJsScriptEngine()
+{
+	rt = JS_NewRuntime(MOZJS_RT_MEMSIZE, JS_NO_HELPER_THREADS);
+	if (!rt) {
+		throw ScriptEngineException{"MozJs JS_NewRuntime failed"};
+	}
+}
+
+MozJsScriptEngine::~MozJsScriptEngine()
+{
+	JS_DestroyRuntime(rt);
+	JS_ShutDown();
+}
+
+MozJsScriptEngineScope *MozJsScriptEngine::createScope()
+{
+	return new MozJsScriptEngineScope(rt);
+}
+}
+}
+
diff --git a/src/plugins/mozjs/MozJsScriptEngine.hpp b/src/plugins/mozjs/MozJsScriptEngine.hpp
new file mode 100644
index 0000000..68eee46
--- /dev/null
+++ b/src/plugins/mozjs/MozJsScriptEngine.hpp
@@ -0,0 +1,76 @@
+/*
+    Ousía
+    Copyright (C) 2014, 2015  Benjamin Paaßen, Andreas Stöckel
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef _MOZ_JS_SCRIPT_ENGINE_HPP_
+#define _MOZ_JS_SCRIPT_ENGINE_HPP_
+
+#include <jsapi.h>
+
+#include <core/script/ScriptEngine.hpp>
+
+namespace ousia {
+namespace script {
+
+class MozJsScriptEngineScope : public ScriptEngineScope {
+
+private:
+	JSRuntime *rt;
+	JSContext *cx;
+	JSCompartment *oldCompartment;
+	JS::RootedObject *global;
+
+	void handleErr(bool ok);
+
+	Variant toVariant(const JS::Value &val);
+
+	std::string toString(const JS::Value &val);
+
+	std::string toString(JSString *str);
+
+protected:
+	Variant doRun(const std::string &code) override;
+	void doSetVariable(const std::string &name, const Variant &val,
+	                   bool constant) override;
+	Variant doGetVariable(const std::string &name) override;
+
+public:
+	MozJsScriptEngineScope(JSRuntime *rt);
+
+	~MozJsScriptEngineScope() override;
+
+};
+
+class MozJsScriptEngine : public ScriptEngine {
+
+private:
+	JSRuntime *rt;
+
+public:
+
+	MozJsScriptEngine();
+
+	~MozJsScriptEngine();
+
+	MozJsScriptEngineScope *createScope() override;
+
+};
+}
+}
+
+#endif /* _MOZ_JS_SCRIPT_ENGINE_HPP_ */
+