gecko-dev/dom/base/nsJSUtils.h

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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef nsJSUtils_h__
#define nsJSUtils_h__
/**
* This is not a generated file. It contains common utility functions
* invoked from the JavaScript code generated from IDL interfaces.
* The goal of the utility functions is to cut down on the size of
* the generated code itself.
*/
#include "mozilla/Assertions.h"
#include "jsapi.h"
#include "jsfriendapi.h"
#include "js/Conversions.h"
#include "nsString.h"
class nsIScriptContext;
class nsIScriptGlobalObject;
namespace mozilla {
namespace dom {
class AutoJSAPI;
class Element;
}
}
class nsJSUtils
{
public:
static bool GetCallingLocation(JSContext* aContext, nsACString& aFilename,
uint32_t* aLineno);
static bool GetCallingLocation(JSContext* aContext, nsAString& aFilename,
uint32_t* aLineno);
static nsIScriptGlobalObject *GetStaticScriptGlobal(JSObject* aObj);
static nsIScriptContext *GetStaticScriptContext(JSObject* aObj);
/**
* Retrieve the inner window ID based on the given JSContext.
*
* @param JSContext aContext
* The JSContext from which you want to find the inner window ID.
*
* @returns uint64_t the inner window ID.
*/
static uint64_t GetCurrentlyRunningCodeInnerWindowID(JSContext *aContext);
/**
* Report a pending exception on aContext, if any. Note that this
* can be called when the context has a JS stack. If that's the
* case, the stack will be set aside before reporting the exception.
*/
static void ReportPendingException(JSContext *aContext);
static nsresult CompileFunction(mozilla::dom::AutoJSAPI& jsapi,
JS::AutoObjectVector& aScopeChain,
JS::CompileOptions& aOptions,
const nsACString& aName,
uint32_t aArgCount,
const char** aArgArray,
const nsAString& aBody,
JSObject** aFunctionObject);
struct MOZ_STACK_CLASS EvaluateOptions {
bool coerceToString;
bool reportUncaught;
JS::AutoObjectVector scopeChain;
explicit EvaluateOptions(JSContext* cx)
: coerceToString(false)
, reportUncaught(true)
, scopeChain(cx)
{}
EvaluateOptions& setCoerceToString(bool aCoerce) {
coerceToString = aCoerce;
return *this;
}
EvaluateOptions& setReportUncaught(bool aReport) {
reportUncaught = aReport;
return *this;
}
};
// aEvaluationGlobal is the global to evaluate in. The return value
// will then be wrapped back into the compartment aCx is in when
// this function is called.
static nsresult EvaluateString(JSContext* aCx,
const nsAString& aScript,
JS::Handle<JSObject*> aEvaluationGlobal,
JS::CompileOptions &aCompileOptions,
const EvaluateOptions& aEvaluateOptions,
JS::MutableHandle<JS::Value> aRetValue);
static nsresult EvaluateString(JSContext* aCx,
JS::SourceBufferHolder& aSrcBuf,
JS::Handle<JSObject*> aEvaluationGlobal,
JS::CompileOptions &aCompileOptions,
const EvaluateOptions& aEvaluateOptions,
JS::MutableHandle<JS::Value> aRetValue);
static nsresult EvaluateString(JSContext* aCx,
const nsAString& aScript,
JS::Handle<JSObject*> aEvaluationGlobal,
JS::CompileOptions &aCompileOptions);
static nsresult EvaluateString(JSContext* aCx,
JS::SourceBufferHolder& aSrcBuf,
JS::Handle<JSObject*> aEvaluationGlobal,
JS::CompileOptions &aCompileOptions,
void **aOffThreadToken);
// Returns false if an exception got thrown on aCx. Passing a null
// aElement is allowed; that wil produce an empty aScopeChain.
static bool GetScopeChainForElement(JSContext* aCx,
mozilla::dom::Element* aElement,
JS::AutoObjectVector& aScopeChain);
private:
// Implementation for our EvaluateString bits
static nsresult EvaluateString(JSContext* aCx,
JS::SourceBufferHolder& aSrcBuf,
JS::Handle<JSObject*> aEvaluationGlobal,
JS::CompileOptions& aCompileOptions,
const EvaluateOptions& aEvaluateOptions,
JS::MutableHandle<JS::Value> aRetValue,
void **aOffThreadToken);
};
class MOZ_STACK_CLASS AutoDontReportUncaught {
JSContext* mContext;
bool mWasSet;
public:
explicit AutoDontReportUncaught(JSContext* aContext) : mContext(aContext) {
MOZ_ASSERT(aContext);
mWasSet = JS::ContextOptionsRef(mContext).dontReportUncaught();
if (!mWasSet) {
JS::ContextOptionsRef(mContext).setDontReportUncaught(true);
}
}
~AutoDontReportUncaught() {
if (!mWasSet) {
JS::ContextOptionsRef(mContext).setDontReportUncaught(false);
}
}
};
template<typename T>
inline bool
AssignJSString(JSContext *cx, T &dest, JSString *s)
{
size_t len = js::GetStringLength(s);
static_assert(js::MaxStringLength < (1 << 28),
"Shouldn't overflow here or in SetCapacity");
if (MOZ_UNLIKELY(!dest.SetLength(len, mozilla::fallible))) {
JS_ReportOutOfMemory(cx);
return false;
}
return js::CopyStringChars(cx, dest.BeginWriting(), s, len);
}
inline void
AssignJSFlatString(nsAString &dest, JSFlatString *s)
{
size_t len = js::GetFlatStringLength(s);
static_assert(js::MaxStringLength < (1 << 28),
"Shouldn't overflow here or in SetCapacity");
dest.SetLength(len);
js::CopyFlatStringChars(dest.BeginWriting(), s, len);
}
class nsAutoJSString : public nsAutoString
{
public:
/**
* nsAutoJSString should be default constructed, which leaves it empty
* (this->IsEmpty()), and initialized with one of the init() methods below.
*/
nsAutoJSString() {}
bool init(JSContext* aContext, JSString* str)
{
return AssignJSString(aContext, *this, str);
}
bool init(JSContext* aContext, const JS::Value &v)
{
if (v.isString()) {
return init(aContext, v.toString());
}
// Stringify, making sure not to run script.
JS::Rooted<JSString*> str(aContext);
if (v.isObject()) {
str = JS_NewStringCopyZ(aContext, "[Object]");
} else {
JS::Rooted<JS::Value> rootedVal(aContext, v);
str = JS::ToString(aContext, rootedVal);
}
return str && init(aContext, str);
}
bool init(JSContext* aContext, jsid id)
{
JS::Rooted<JS::Value> v(aContext);
return JS_IdToValue(aContext, id, &v) && init(aContext, v);
}
bool init(const JS::Value &v);
~nsAutoJSString() {}
};
#endif /* nsJSUtils_h__ */