1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/dom/base/nsJSUtils.cpp Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,338 @@
1.4 +/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
1.5 +/* vim: set ts=2 sw=2 et tw=78: */
1.6 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.7 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.8 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.9 +
1.10 +/**
1.11 + * This is not a generated file. It contains common utility functions
1.12 + * invoked from the JavaScript code generated from IDL interfaces.
1.13 + * The goal of the utility functions is to cut down on the size of
1.14 + * the generated code itself.
1.15 + */
1.16 +
1.17 +#include "nsJSUtils.h"
1.18 +#include "jsapi.h"
1.19 +#include "js/OldDebugAPI.h"
1.20 +#include "jsfriendapi.h"
1.21 +#include "nsIScriptContext.h"
1.22 +#include "nsIScriptGlobalObject.h"
1.23 +#include "nsIXPConnect.h"
1.24 +#include "nsCOMPtr.h"
1.25 +#include "nsIScriptSecurityManager.h"
1.26 +#include "nsPIDOMWindow.h"
1.27 +#include "GeckoProfiler.h"
1.28 +#include "nsDOMJSUtils.h" // for GetScriptContextFromJSContext
1.29 +#include "nsJSPrincipals.h"
1.30 +#include "xpcpublic.h"
1.31 +#include "nsContentUtils.h"
1.32 +#include "nsGlobalWindow.h"
1.33 +
1.34 +bool
1.35 +nsJSUtils::GetCallingLocation(JSContext* aContext, const char* *aFilename,
1.36 + uint32_t* aLineno)
1.37 +{
1.38 + JS::AutoFilename filename;
1.39 + unsigned lineno = 0;
1.40 +
1.41 + if (!JS::DescribeScriptedCaller(aContext, &filename, &lineno)) {
1.42 + return false;
1.43 + }
1.44 +
1.45 + *aFilename = filename.get();
1.46 + *aLineno = lineno;
1.47 +
1.48 + return true;
1.49 +}
1.50 +
1.51 +nsIScriptGlobalObject *
1.52 +nsJSUtils::GetStaticScriptGlobal(JSObject* aObj)
1.53 +{
1.54 + if (!aObj)
1.55 + return nullptr;
1.56 + return xpc::WindowGlobalOrNull(aObj);
1.57 +}
1.58 +
1.59 +nsIScriptContext *
1.60 +nsJSUtils::GetStaticScriptContext(JSObject* aObj)
1.61 +{
1.62 + nsIScriptGlobalObject *nativeGlobal = GetStaticScriptGlobal(aObj);
1.63 + if (!nativeGlobal)
1.64 + return nullptr;
1.65 +
1.66 + return nativeGlobal->GetScriptContext();
1.67 +}
1.68 +
1.69 +nsIScriptGlobalObject *
1.70 +nsJSUtils::GetDynamicScriptGlobal(JSContext* aContext)
1.71 +{
1.72 + nsIScriptContext *scriptCX = GetDynamicScriptContext(aContext);
1.73 + if (!scriptCX)
1.74 + return nullptr;
1.75 + return scriptCX->GetGlobalObject();
1.76 +}
1.77 +
1.78 +nsIScriptContext *
1.79 +nsJSUtils::GetDynamicScriptContext(JSContext *aContext)
1.80 +{
1.81 + return GetScriptContextFromJSContext(aContext);
1.82 +}
1.83 +
1.84 +uint64_t
1.85 +nsJSUtils::GetCurrentlyRunningCodeInnerWindowID(JSContext *aContext)
1.86 +{
1.87 + if (!aContext)
1.88 + return 0;
1.89 +
1.90 + uint64_t innerWindowID = 0;
1.91 +
1.92 + JSObject *jsGlobal = JS::CurrentGlobalOrNull(aContext);
1.93 + if (jsGlobal) {
1.94 + nsIScriptGlobalObject *scriptGlobal = GetStaticScriptGlobal(jsGlobal);
1.95 + if (scriptGlobal) {
1.96 + nsCOMPtr<nsPIDOMWindow> win = do_QueryInterface(scriptGlobal);
1.97 + if (win)
1.98 + innerWindowID = win->WindowID();
1.99 + }
1.100 + }
1.101 +
1.102 + return innerWindowID;
1.103 +}
1.104 +
1.105 +void
1.106 +nsJSUtils::ReportPendingException(JSContext *aContext)
1.107 +{
1.108 + if (JS_IsExceptionPending(aContext)) {
1.109 + bool saved = JS_SaveFrameChain(aContext);
1.110 + {
1.111 + // JS_SaveFrameChain set the compartment of aContext to null, so we need
1.112 + // to enter a compartment. The question is, which one? We don't want to
1.113 + // enter the original compartment of aContext (or the compartment of the
1.114 + // current exception on aContext, for that matter) because when we
1.115 + // JS_ReportPendingException the JS engine can try to duck-type the
1.116 + // exception and produce a JSErrorReport. It will then pass that
1.117 + // JSErrorReport to the error reporter on aContext, which might expose
1.118 + // information from it to script via onerror handlers. So it's very
1.119 + // important that the duck typing happen in the same compartment as the
1.120 + // onerror handler. In practice, that's the compartment of the window (or
1.121 + // otherwise default global) of aContext, so use that here.
1.122 + nsIScriptContext* scx = GetScriptContextFromJSContext(aContext);
1.123 + JS::Rooted<JSObject*> scope(aContext);
1.124 + scope = scx ? scx->GetWindowProxy()
1.125 + : js::DefaultObjectForContextOrNull(aContext);
1.126 + if (!scope) {
1.127 + // The SafeJSContext has no default object associated with it.
1.128 + MOZ_ASSERT(NS_IsMainThread());
1.129 + MOZ_ASSERT(aContext == nsContentUtils::GetSafeJSContext());
1.130 + scope = xpc::GetSafeJSContextGlobal();
1.131 + }
1.132 + JSAutoCompartment ac(aContext, scope);
1.133 + JS_ReportPendingException(aContext);
1.134 + }
1.135 + if (saved) {
1.136 + JS_RestoreFrameChain(aContext);
1.137 + }
1.138 + }
1.139 +}
1.140 +
1.141 +nsresult
1.142 +nsJSUtils::CompileFunction(JSContext* aCx,
1.143 + JS::Handle<JSObject*> aTarget,
1.144 + JS::CompileOptions& aOptions,
1.145 + const nsACString& aName,
1.146 + uint32_t aArgCount,
1.147 + const char** aArgArray,
1.148 + const nsAString& aBody,
1.149 + JSObject** aFunctionObject)
1.150 +{
1.151 + MOZ_ASSERT(js::GetEnterCompartmentDepth(aCx) > 0);
1.152 + MOZ_ASSERT_IF(aTarget, js::IsObjectInContextCompartment(aTarget, aCx));
1.153 + MOZ_ASSERT_IF(aOptions.versionSet, aOptions.version != JSVERSION_UNKNOWN);
1.154 + mozilla::DebugOnly<nsIScriptContext*> ctx = GetScriptContextFromJSContext(aCx);
1.155 + MOZ_ASSERT_IF(ctx, ctx->IsContextInitialized());
1.156 +
1.157 + // Do the junk Gecko is supposed to do before calling into JSAPI.
1.158 + if (aTarget) {
1.159 + JS::ExposeObjectToActiveJS(aTarget);
1.160 + }
1.161 +
1.162 + // Compile.
1.163 + JSFunction* fun = JS::CompileFunction(aCx, aTarget, aOptions,
1.164 + PromiseFlatCString(aName).get(),
1.165 + aArgCount, aArgArray,
1.166 + PromiseFlatString(aBody).get(),
1.167 + aBody.Length());
1.168 + if (!fun) {
1.169 + ReportPendingException(aCx);
1.170 + return NS_ERROR_FAILURE;
1.171 + }
1.172 +
1.173 + *aFunctionObject = JS_GetFunctionObject(fun);
1.174 + return NS_OK;
1.175 +}
1.176 +
1.177 +nsresult
1.178 +nsJSUtils::EvaluateString(JSContext* aCx,
1.179 + const nsAString& aScript,
1.180 + JS::Handle<JSObject*> aScopeObject,
1.181 + JS::CompileOptions& aCompileOptions,
1.182 + const EvaluateOptions& aEvaluateOptions,
1.183 + JS::MutableHandle<JS::Value> aRetValue,
1.184 + void **aOffThreadToken)
1.185 +{
1.186 + const nsPromiseFlatString& flatScript = PromiseFlatString(aScript);
1.187 + JS::SourceBufferHolder srcBuf(flatScript.get(), aScript.Length(),
1.188 + JS::SourceBufferHolder::NoOwnership);
1.189 + return EvaluateString(aCx, srcBuf, aScopeObject, aCompileOptions,
1.190 + aEvaluateOptions, aRetValue, aOffThreadToken);
1.191 +}
1.192 +
1.193 +nsresult
1.194 +nsJSUtils::EvaluateString(JSContext* aCx,
1.195 + JS::SourceBufferHolder& aSrcBuf,
1.196 + JS::Handle<JSObject*> aScopeObject,
1.197 + JS::CompileOptions& aCompileOptions,
1.198 + const EvaluateOptions& aEvaluateOptions,
1.199 + JS::MutableHandle<JS::Value> aRetValue,
1.200 + void **aOffThreadToken)
1.201 +{
1.202 + PROFILER_LABEL("JS", "EvaluateString");
1.203 + MOZ_ASSERT_IF(aCompileOptions.versionSet,
1.204 + aCompileOptions.version != JSVERSION_UNKNOWN);
1.205 + MOZ_ASSERT_IF(aEvaluateOptions.coerceToString, aEvaluateOptions.needResult);
1.206 + MOZ_ASSERT_IF(!aEvaluateOptions.reportUncaught, aEvaluateOptions.needResult);
1.207 + MOZ_ASSERT(aCx == nsContentUtils::GetCurrentJSContext());
1.208 + MOZ_ASSERT(aSrcBuf.get());
1.209 +
1.210 + // Unfortunately, the JS engine actually compiles scripts with a return value
1.211 + // in a different, less efficient way. Furthermore, it can't JIT them in many
1.212 + // cases. So we need to be explicitly told whether the caller cares about the
1.213 + // return value. Callers can do this by calling the other overload of
1.214 + // EvaluateString() which calls this function with aEvaluateOptions.needResult
1.215 + // set to false.
1.216 + aRetValue.setUndefined();
1.217 +
1.218 + JS::ExposeObjectToActiveJS(aScopeObject);
1.219 + nsAutoMicroTask mt;
1.220 + nsresult rv = NS_OK;
1.221 +
1.222 + bool ok = false;
1.223 + nsIScriptSecurityManager* ssm = nsContentUtils::GetSecurityManager();
1.224 + NS_ENSURE_TRUE(ssm->ScriptAllowed(js::GetGlobalForObjectCrossCompartment(aScopeObject)), NS_OK);
1.225 +
1.226 + mozilla::Maybe<AutoDontReportUncaught> dontReport;
1.227 + if (!aEvaluateOptions.reportUncaught) {
1.228 + // We need to prevent AutoLastFrameCheck from reporting and clearing
1.229 + // any pending exceptions.
1.230 + dontReport.construct(aCx);
1.231 + }
1.232 +
1.233 + // Scope the JSAutoCompartment so that we can later wrap the return value
1.234 + // into the caller's cx.
1.235 + {
1.236 + JSAutoCompartment ac(aCx, aScopeObject);
1.237 +
1.238 + JS::Rooted<JSObject*> rootedScope(aCx, aScopeObject);
1.239 + if (aOffThreadToken) {
1.240 + JS::Rooted<JSScript*>
1.241 + script(aCx, JS::FinishOffThreadScript(aCx, JS_GetRuntime(aCx), *aOffThreadToken));
1.242 + *aOffThreadToken = nullptr; // Mark the token as having been finished.
1.243 + if (script) {
1.244 + if (aEvaluateOptions.needResult) {
1.245 + ok = JS_ExecuteScript(aCx, rootedScope, script, aRetValue);
1.246 + } else {
1.247 + ok = JS_ExecuteScript(aCx, rootedScope, script);
1.248 + }
1.249 + } else {
1.250 + ok = false;
1.251 + }
1.252 + } else {
1.253 + if (aEvaluateOptions.needResult) {
1.254 + ok = JS::Evaluate(aCx, rootedScope, aCompileOptions,
1.255 + aSrcBuf, aRetValue);
1.256 + } else {
1.257 + ok = JS::Evaluate(aCx, rootedScope, aCompileOptions,
1.258 + aSrcBuf);
1.259 + }
1.260 + }
1.261 +
1.262 + if (ok && aEvaluateOptions.coerceToString && !aRetValue.isUndefined()) {
1.263 + JS::Rooted<JS::Value> value(aCx, aRetValue);
1.264 + JSString* str = JS::ToString(aCx, value);
1.265 + ok = !!str;
1.266 + aRetValue.set(ok ? JS::StringValue(str) : JS::UndefinedValue());
1.267 + }
1.268 + }
1.269 +
1.270 + if (!ok) {
1.271 + if (aEvaluateOptions.reportUncaught) {
1.272 + ReportPendingException(aCx);
1.273 + if (aEvaluateOptions.needResult) {
1.274 + aRetValue.setUndefined();
1.275 + }
1.276 + } else {
1.277 + rv = JS_IsExceptionPending(aCx) ? NS_ERROR_FAILURE
1.278 + : NS_ERROR_OUT_OF_MEMORY;
1.279 + JS::Rooted<JS::Value> exn(aCx);
1.280 + JS_GetPendingException(aCx, &exn);
1.281 + if (aEvaluateOptions.needResult) {
1.282 + aRetValue.set(exn);
1.283 + }
1.284 + JS_ClearPendingException(aCx);
1.285 + }
1.286 + }
1.287 +
1.288 + // Wrap the return value into whatever compartment aCx was in.
1.289 + if (aEvaluateOptions.needResult) {
1.290 + JS::Rooted<JS::Value> v(aCx, aRetValue);
1.291 + if (!JS_WrapValue(aCx, &v)) {
1.292 + return NS_ERROR_OUT_OF_MEMORY;
1.293 + }
1.294 + aRetValue.set(v);
1.295 + }
1.296 + return rv;
1.297 +}
1.298 +
1.299 +nsresult
1.300 +nsJSUtils::EvaluateString(JSContext* aCx,
1.301 + const nsAString& aScript,
1.302 + JS::Handle<JSObject*> aScopeObject,
1.303 + JS::CompileOptions& aCompileOptions,
1.304 + void **aOffThreadToken)
1.305 +{
1.306 + EvaluateOptions options;
1.307 + options.setNeedResult(false);
1.308 + JS::RootedValue unused(aCx);
1.309 + return EvaluateString(aCx, aScript, aScopeObject, aCompileOptions,
1.310 + options, &unused, aOffThreadToken);
1.311 +}
1.312 +
1.313 +nsresult
1.314 +nsJSUtils::EvaluateString(JSContext* aCx,
1.315 + JS::SourceBufferHolder& aSrcBuf,
1.316 + JS::Handle<JSObject*> aScopeObject,
1.317 + JS::CompileOptions& aCompileOptions,
1.318 + void **aOffThreadToken)
1.319 +{
1.320 + EvaluateOptions options;
1.321 + options.setNeedResult(false);
1.322 + JS::RootedValue unused(aCx);
1.323 + return EvaluateString(aCx, aSrcBuf, aScopeObject, aCompileOptions,
1.324 + options, &unused, aOffThreadToken);
1.325 +}
1.326 +
1.327 +//
1.328 +// nsDOMJSUtils.h
1.329 +//
1.330 +
1.331 +JSObject* GetDefaultScopeFromJSContext(JSContext *cx)
1.332 +{
1.333 + // DOM JSContexts don't store their default compartment object on
1.334 + // the cx, so in those cases we need to fetch it via the scx
1.335 + // instead.
1.336 + nsIScriptContext *scx = GetScriptContextFromJSContext(cx);
1.337 + if (scx) {
1.338 + return scx->GetWindowProxy();
1.339 + }
1.340 + return js::DefaultObjectForContextOrNull(cx);
1.341 +}
