michael@0: /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
michael@0: /* vim: set ts=2 sw=2 et tw=78: */
michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: /**
michael@0:  * This is not a generated file. It contains common utility functions
michael@0:  * invoked from the JavaScript code generated from IDL interfaces.
michael@0:  * The goal of the utility functions is to cut down on the size of
michael@0:  * the generated code itself.
michael@0:  */
michael@0: 
michael@0: #include "nsJSUtils.h"
michael@0: #include "jsapi.h"
michael@0: #include "js/OldDebugAPI.h"
michael@0: #include "jsfriendapi.h"
michael@0: #include "nsIScriptContext.h"
michael@0: #include "nsIScriptGlobalObject.h"
michael@0: #include "nsIXPConnect.h"
michael@0: #include "nsCOMPtr.h"
michael@0: #include "nsIScriptSecurityManager.h"
michael@0: #include "nsPIDOMWindow.h"
michael@0: #include "GeckoProfiler.h"
michael@0: #include "nsDOMJSUtils.h" // for GetScriptContextFromJSContext
michael@0: #include "nsJSPrincipals.h"
michael@0: #include "xpcpublic.h"
michael@0: #include "nsContentUtils.h"
michael@0: #include "nsGlobalWindow.h"
michael@0: 
michael@0: bool
michael@0: nsJSUtils::GetCallingLocation(JSContext* aContext, const char* *aFilename,
michael@0:                               uint32_t* aLineno)
michael@0: {
michael@0:   JS::AutoFilename filename;
michael@0:   unsigned lineno = 0;
michael@0: 
michael@0:   if (!JS::DescribeScriptedCaller(aContext, &filename, &lineno)) {
michael@0:     return false;
michael@0:   }
michael@0: 
michael@0:   *aFilename = filename.get();
michael@0:   *aLineno = lineno;
michael@0: 
michael@0:   return true;
michael@0: }
michael@0: 
michael@0: nsIScriptGlobalObject *
michael@0: nsJSUtils::GetStaticScriptGlobal(JSObject* aObj)
michael@0: {
michael@0:   if (!aObj)
michael@0:     return nullptr;
michael@0:   return xpc::WindowGlobalOrNull(aObj);
michael@0: }
michael@0: 
michael@0: nsIScriptContext *
michael@0: nsJSUtils::GetStaticScriptContext(JSObject* aObj)
michael@0: {
michael@0:   nsIScriptGlobalObject *nativeGlobal = GetStaticScriptGlobal(aObj);
michael@0:   if (!nativeGlobal)
michael@0:     return nullptr;
michael@0: 
michael@0:   return nativeGlobal->GetScriptContext();
michael@0: }
michael@0: 
michael@0: nsIScriptGlobalObject *
michael@0: nsJSUtils::GetDynamicScriptGlobal(JSContext* aContext)
michael@0: {
michael@0:   nsIScriptContext *scriptCX = GetDynamicScriptContext(aContext);
michael@0:   if (!scriptCX)
michael@0:     return nullptr;
michael@0:   return scriptCX->GetGlobalObject();
michael@0: }
michael@0: 
michael@0: nsIScriptContext *
michael@0: nsJSUtils::GetDynamicScriptContext(JSContext *aContext)
michael@0: {
michael@0:   return GetScriptContextFromJSContext(aContext);
michael@0: }
michael@0: 
michael@0: uint64_t
michael@0: nsJSUtils::GetCurrentlyRunningCodeInnerWindowID(JSContext *aContext)
michael@0: {
michael@0:   if (!aContext)
michael@0:     return 0;
michael@0: 
michael@0:   uint64_t innerWindowID = 0;
michael@0: 
michael@0:   JSObject *jsGlobal = JS::CurrentGlobalOrNull(aContext);
michael@0:   if (jsGlobal) {
michael@0:     nsIScriptGlobalObject *scriptGlobal = GetStaticScriptGlobal(jsGlobal);
michael@0:     if (scriptGlobal) {
michael@0:       nsCOMPtr<nsPIDOMWindow> win = do_QueryInterface(scriptGlobal);
michael@0:       if (win)
michael@0:         innerWindowID = win->WindowID();
michael@0:     }
michael@0:   }
michael@0: 
michael@0:   return innerWindowID;
michael@0: }
michael@0: 
michael@0: void
michael@0: nsJSUtils::ReportPendingException(JSContext *aContext)
michael@0: {
michael@0:   if (JS_IsExceptionPending(aContext)) {
michael@0:     bool saved = JS_SaveFrameChain(aContext);
michael@0:     {
michael@0:       // JS_SaveFrameChain set the compartment of aContext to null, so we need
michael@0:       // to enter a compartment.  The question is, which one? We don't want to
michael@0:       // enter the original compartment of aContext (or the compartment of the
michael@0:       // current exception on aContext, for that matter) because when we
michael@0:       // JS_ReportPendingException the JS engine can try to duck-type the
michael@0:       // exception and produce a JSErrorReport.  It will then pass that
michael@0:       // JSErrorReport to the error reporter on aContext, which might expose
michael@0:       // information from it to script via onerror handlers.  So it's very
michael@0:       // important that the duck typing happen in the same compartment as the
michael@0:       // onerror handler.  In practice, that's the compartment of the window (or
michael@0:       // otherwise default global) of aContext, so use that here.
michael@0:       nsIScriptContext* scx = GetScriptContextFromJSContext(aContext);
michael@0:       JS::Rooted<JSObject*> scope(aContext);
michael@0:       scope = scx ? scx->GetWindowProxy()
michael@0:                   : js::DefaultObjectForContextOrNull(aContext);
michael@0:       if (!scope) {
michael@0:         // The SafeJSContext has no default object associated with it.
michael@0:         MOZ_ASSERT(NS_IsMainThread());
michael@0:         MOZ_ASSERT(aContext == nsContentUtils::GetSafeJSContext());
michael@0:         scope = xpc::GetSafeJSContextGlobal();
michael@0:       }
michael@0:       JSAutoCompartment ac(aContext, scope);
michael@0:       JS_ReportPendingException(aContext);
michael@0:     }
michael@0:     if (saved) {
michael@0:       JS_RestoreFrameChain(aContext);
michael@0:     }
michael@0:   }
michael@0: }
michael@0: 
michael@0: nsresult
michael@0: nsJSUtils::CompileFunction(JSContext* aCx,
michael@0:                            JS::Handle<JSObject*> aTarget,
michael@0:                            JS::CompileOptions& aOptions,
michael@0:                            const nsACString& aName,
michael@0:                            uint32_t aArgCount,
michael@0:                            const char** aArgArray,
michael@0:                            const nsAString& aBody,
michael@0:                            JSObject** aFunctionObject)
michael@0: {
michael@0:   MOZ_ASSERT(js::GetEnterCompartmentDepth(aCx) > 0);
michael@0:   MOZ_ASSERT_IF(aTarget, js::IsObjectInContextCompartment(aTarget, aCx));
michael@0:   MOZ_ASSERT_IF(aOptions.versionSet, aOptions.version != JSVERSION_UNKNOWN);
michael@0:   mozilla::DebugOnly<nsIScriptContext*> ctx = GetScriptContextFromJSContext(aCx);
michael@0:   MOZ_ASSERT_IF(ctx, ctx->IsContextInitialized());
michael@0: 
michael@0:   // Do the junk Gecko is supposed to do before calling into JSAPI.
michael@0:   if (aTarget) {
michael@0:     JS::ExposeObjectToActiveJS(aTarget);
michael@0:   }
michael@0: 
michael@0:   // Compile.
michael@0:   JSFunction* fun = JS::CompileFunction(aCx, aTarget, aOptions,
michael@0:                                         PromiseFlatCString(aName).get(),
michael@0:                                         aArgCount, aArgArray,
michael@0:                                         PromiseFlatString(aBody).get(),
michael@0:                                         aBody.Length());
michael@0:   if (!fun) {
michael@0:     ReportPendingException(aCx);
michael@0:     return NS_ERROR_FAILURE;
michael@0:   }
michael@0: 
michael@0:   *aFunctionObject = JS_GetFunctionObject(fun);
michael@0:   return NS_OK;
michael@0: }
michael@0: 
michael@0: nsresult
michael@0: nsJSUtils::EvaluateString(JSContext* aCx,
michael@0:                           const nsAString& aScript,
michael@0:                           JS::Handle<JSObject*> aScopeObject,
michael@0:                           JS::CompileOptions& aCompileOptions,
michael@0:                           const EvaluateOptions& aEvaluateOptions,
michael@0:                           JS::MutableHandle<JS::Value> aRetValue,
michael@0:                           void **aOffThreadToken)
michael@0: {
michael@0:   const nsPromiseFlatString& flatScript = PromiseFlatString(aScript);
michael@0:   JS::SourceBufferHolder srcBuf(flatScript.get(), aScript.Length(),
michael@0:                                 JS::SourceBufferHolder::NoOwnership);
michael@0:   return EvaluateString(aCx, srcBuf, aScopeObject, aCompileOptions,
michael@0:                         aEvaluateOptions, aRetValue, aOffThreadToken);
michael@0: }
michael@0: 
michael@0: nsresult
michael@0: nsJSUtils::EvaluateString(JSContext* aCx,
michael@0:                           JS::SourceBufferHolder& aSrcBuf,
michael@0:                           JS::Handle<JSObject*> aScopeObject,
michael@0:                           JS::CompileOptions& aCompileOptions,
michael@0:                           const EvaluateOptions& aEvaluateOptions,
michael@0:                           JS::MutableHandle<JS::Value> aRetValue,
michael@0:                           void **aOffThreadToken)
michael@0: {
michael@0:   PROFILER_LABEL("JS", "EvaluateString");
michael@0:   MOZ_ASSERT_IF(aCompileOptions.versionSet,
michael@0:                 aCompileOptions.version != JSVERSION_UNKNOWN);
michael@0:   MOZ_ASSERT_IF(aEvaluateOptions.coerceToString, aEvaluateOptions.needResult);
michael@0:   MOZ_ASSERT_IF(!aEvaluateOptions.reportUncaught, aEvaluateOptions.needResult);
michael@0:   MOZ_ASSERT(aCx == nsContentUtils::GetCurrentJSContext());
michael@0:   MOZ_ASSERT(aSrcBuf.get());
michael@0: 
michael@0:   // Unfortunately, the JS engine actually compiles scripts with a return value
michael@0:   // in a different, less efficient way.  Furthermore, it can't JIT them in many
michael@0:   // cases.  So we need to be explicitly told whether the caller cares about the
michael@0:   // return value.  Callers can do this by calling the other overload of
michael@0:   // EvaluateString() which calls this function with aEvaluateOptions.needResult
michael@0:   // set to false.
michael@0:   aRetValue.setUndefined();
michael@0: 
michael@0:   JS::ExposeObjectToActiveJS(aScopeObject);
michael@0:   nsAutoMicroTask mt;
michael@0:   nsresult rv = NS_OK;
michael@0: 
michael@0:   bool ok = false;
michael@0:   nsIScriptSecurityManager* ssm = nsContentUtils::GetSecurityManager();
michael@0:   NS_ENSURE_TRUE(ssm->ScriptAllowed(js::GetGlobalForObjectCrossCompartment(aScopeObject)), NS_OK);
michael@0: 
michael@0:   mozilla::Maybe<AutoDontReportUncaught> dontReport;
michael@0:   if (!aEvaluateOptions.reportUncaught) {
michael@0:     // We need to prevent AutoLastFrameCheck from reporting and clearing
michael@0:     // any pending exceptions.
michael@0:     dontReport.construct(aCx);
michael@0:   }
michael@0: 
michael@0:   // Scope the JSAutoCompartment so that we can later wrap the return value
michael@0:   // into the caller's cx.
michael@0:   {
michael@0:     JSAutoCompartment ac(aCx, aScopeObject);
michael@0: 
michael@0:     JS::Rooted<JSObject*> rootedScope(aCx, aScopeObject);
michael@0:     if (aOffThreadToken) {
michael@0:       JS::Rooted<JSScript*>
michael@0:         script(aCx, JS::FinishOffThreadScript(aCx, JS_GetRuntime(aCx), *aOffThreadToken));
michael@0:       *aOffThreadToken = nullptr; // Mark the token as having been finished.
michael@0:       if (script) {
michael@0:         if (aEvaluateOptions.needResult) {
michael@0:           ok = JS_ExecuteScript(aCx, rootedScope, script, aRetValue);
michael@0:         } else {
michael@0:           ok = JS_ExecuteScript(aCx, rootedScope, script);
michael@0:         }
michael@0:       } else {
michael@0:         ok = false;
michael@0:       }
michael@0:     } else {
michael@0:       if (aEvaluateOptions.needResult) {
michael@0:         ok = JS::Evaluate(aCx, rootedScope, aCompileOptions,
michael@0:                           aSrcBuf, aRetValue);
michael@0:       } else {
michael@0:         ok = JS::Evaluate(aCx, rootedScope, aCompileOptions,
michael@0:                           aSrcBuf);
michael@0:       }
michael@0:     }
michael@0: 
michael@0:     if (ok && aEvaluateOptions.coerceToString && !aRetValue.isUndefined()) {
michael@0:       JS::Rooted<JS::Value> value(aCx, aRetValue);
michael@0:       JSString* str = JS::ToString(aCx, value);
michael@0:       ok = !!str;
michael@0:       aRetValue.set(ok ? JS::StringValue(str) : JS::UndefinedValue());
michael@0:     }
michael@0:   }
michael@0: 
michael@0:   if (!ok) {
michael@0:     if (aEvaluateOptions.reportUncaught) {
michael@0:       ReportPendingException(aCx);
michael@0:       if (aEvaluateOptions.needResult) {
michael@0:         aRetValue.setUndefined();
michael@0:       }
michael@0:     } else {
michael@0:       rv = JS_IsExceptionPending(aCx) ? NS_ERROR_FAILURE
michael@0:                                       : NS_ERROR_OUT_OF_MEMORY;
michael@0:       JS::Rooted<JS::Value> exn(aCx);
michael@0:       JS_GetPendingException(aCx, &exn);
michael@0:       if (aEvaluateOptions.needResult) {
michael@0:         aRetValue.set(exn);
michael@0:       }
michael@0:       JS_ClearPendingException(aCx);
michael@0:     }
michael@0:   }
michael@0: 
michael@0:   // Wrap the return value into whatever compartment aCx was in.
michael@0:   if (aEvaluateOptions.needResult) {
michael@0:     JS::Rooted<JS::Value> v(aCx, aRetValue);
michael@0:     if (!JS_WrapValue(aCx, &v)) {
michael@0:       return NS_ERROR_OUT_OF_MEMORY;
michael@0:     }
michael@0:     aRetValue.set(v);
michael@0:   }
michael@0:   return rv;
michael@0: }
michael@0: 
michael@0: nsresult
michael@0: nsJSUtils::EvaluateString(JSContext* aCx,
michael@0:                           const nsAString& aScript,
michael@0:                           JS::Handle<JSObject*> aScopeObject,
michael@0:                           JS::CompileOptions& aCompileOptions,
michael@0:                           void **aOffThreadToken)
michael@0: {
michael@0:   EvaluateOptions options;
michael@0:   options.setNeedResult(false);
michael@0:   JS::RootedValue unused(aCx);
michael@0:   return EvaluateString(aCx, aScript, aScopeObject, aCompileOptions,
michael@0:                         options, &unused, aOffThreadToken);
michael@0: }
michael@0: 
michael@0: nsresult
michael@0: nsJSUtils::EvaluateString(JSContext* aCx,
michael@0:                           JS::SourceBufferHolder& aSrcBuf,
michael@0:                           JS::Handle<JSObject*> aScopeObject,
michael@0:                           JS::CompileOptions& aCompileOptions,
michael@0:                           void **aOffThreadToken)
michael@0: {
michael@0:   EvaluateOptions options;
michael@0:   options.setNeedResult(false);
michael@0:   JS::RootedValue unused(aCx);
michael@0:   return EvaluateString(aCx, aSrcBuf, aScopeObject, aCompileOptions,
michael@0:                         options, &unused, aOffThreadToken);
michael@0: }
michael@0: 
michael@0: //
michael@0: // nsDOMJSUtils.h
michael@0: //
michael@0: 
michael@0: JSObject* GetDefaultScopeFromJSContext(JSContext *cx)
michael@0: {
michael@0:   // DOM JSContexts don't store their default compartment object on
michael@0:   // the cx, so in those cases we need to fetch it via the scx
michael@0:   // instead.
michael@0:   nsIScriptContext *scx = GetScriptContextFromJSContext(cx);
michael@0:   if (scx) {
michael@0:     return scx->GetWindowProxy();
michael@0:   }
michael@0:   return js::DefaultObjectForContextOrNull(cx);
michael@0: }