gecko/dom/bindings/Exceptions.cpp

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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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/. */
#include "mozilla/dom/Exceptions.h"
#include "js/GCAPI.h"
#include "js/OldDebugAPI.h"
#include "jsapi.h"
#include "jsprf.h"
#include "mozilla/CycleCollectedJSRuntime.h"
#include "mozilla/dom/BindingUtils.h"
#include "mozilla/dom/DOMException.h"
#include "nsServiceManagerUtils.h"
#include "nsThreadUtils.h"
#include "XPCWrapper.h"
#include "WorkerPrivate.h"
#include "nsContentUtils.h"
namespace mozilla {
namespace dom {
bool
ThrowExceptionObject(JSContext* aCx, nsIException* aException)
{
// See if we really have an Exception.
nsCOMPtr<Exception> exception = do_QueryInterface(aException);
if (exception) {
return ThrowExceptionObject(aCx, exception);
}
// We only have an nsIException (probably an XPCWrappedJS). Fall back on old
// wrapping.
MOZ_ASSERT(NS_IsMainThread());
JS::Rooted<JSObject*> glob(aCx, JS::CurrentGlobalOrNull(aCx));
if (!glob) {
// XXXbz Can this really be null here?
return false;
}
JS::Rooted<JS::Value> val(aCx);
if (!WrapObject(aCx, aException, &NS_GET_IID(nsIException), &val)) {
return false;
}
JS_SetPendingException(aCx, val);
return true;
}
bool
ThrowExceptionObject(JSContext* aCx, Exception* aException)
{
JS::Rooted<JS::Value> thrown(aCx);
// If we stored the original thrown JS value in the exception
// (see XPCConvert::ConstructException) and we are in a web context
// (i.e., not chrome), rethrow the original value. This only applies to JS
// implemented components so we only need to check for this on the main
// thread.
if (NS_IsMainThread() && !nsContentUtils::IsCallerChrome() &&
aException->StealJSVal(thrown.address())) {
if (!JS_WrapValue(aCx, &thrown)) {
return false;
}
JS_SetPendingException(aCx, thrown);
return true;
}
JS::Rooted<JSObject*> glob(aCx, JS::CurrentGlobalOrNull(aCx));
if (!glob) {
// XXXbz Can this actually be null here?
return false;
}
if (!WrapNewBindingObject(aCx, aException, &thrown)) {
return false;
}
JS_SetPendingException(aCx, thrown);
return true;
}
bool
Throw(JSContext* aCx, nsresult aRv, const char* aMessage)
{
if (JS_IsExceptionPending(aCx)) {
// Don't clobber the existing exception.
return false;
}
CycleCollectedJSRuntime* runtime = CycleCollectedJSRuntime::Get();
nsCOMPtr<nsIException> existingException = runtime->GetPendingException();
if (existingException) {
nsresult nr;
if (NS_SUCCEEDED(existingException->GetResult(&nr)) &&
aRv == nr) {
// Reuse the existing exception.
// Clear pending exception
runtime->SetPendingException(nullptr);
if (!ThrowExceptionObject(aCx, existingException)) {
// If we weren't able to throw an exception we're
// most likely out of memory
JS_ReportOutOfMemory(aCx);
}
return false;
}
}
nsRefPtr<Exception> finalException = CreateException(aCx, aRv, aMessage);
MOZ_ASSERT(finalException);
if (!ThrowExceptionObject(aCx, finalException)) {
// If we weren't able to throw an exception we're
// most likely out of memory
JS_ReportOutOfMemory(aCx);
}
return false;
}
already_AddRefed<Exception>
CreateException(JSContext* aCx, nsresult aRv, const char* aMessage)
{
// Do we use DOM exceptions for this error code?
switch (NS_ERROR_GET_MODULE(aRv)) {
case NS_ERROR_MODULE_DOM:
case NS_ERROR_MODULE_SVG:
case NS_ERROR_MODULE_DOM_XPATH:
case NS_ERROR_MODULE_DOM_INDEXEDDB:
case NS_ERROR_MODULE_DOM_FILEHANDLE:
return DOMException::Create(aRv);
default:
break;
}
// If not, use the default.
// aMessage can be null, so we can't use nsDependentCString on it.
nsRefPtr<Exception> exception =
new Exception(nsCString(aMessage), aRv,
EmptyCString(), nullptr, nullptr);
return exception.forget();
}
already_AddRefed<nsIStackFrame>
GetCurrentJSStack()
{
// is there a current context available?
JSContext* cx = nullptr;
if (NS_IsMainThread()) {
MOZ_ASSERT(nsContentUtils::XPConnect());
cx = nsContentUtils::GetCurrentJSContext();
} else {
cx = workers::GetCurrentThreadJSContext();
}
if (!cx) {
return nullptr;
}
nsCOMPtr<nsIStackFrame> stack = exceptions::CreateStack(cx);
if (!stack) {
return nullptr;
}
// peel off native frames...
uint32_t language;
nsCOMPtr<nsIStackFrame> caller;
while (stack &&
NS_SUCCEEDED(stack->GetLanguage(&language)) &&
language != nsIProgrammingLanguage::JAVASCRIPT &&
NS_SUCCEEDED(stack->GetCaller(getter_AddRefs(caller))) &&
caller) {
stack = caller;
}
return stack.forget();
}
namespace exceptions {
class StackDescriptionOwner {
public:
StackDescriptionOwner(JS::StackDescription* aDescription)
: mDescription(aDescription)
{
mozilla::HoldJSObjects(this);
}
~StackDescriptionOwner()
{
// Make sure to set mDescription to null before calling DropJSObjects, since
// in debug builds DropJSObjects try to trace us and we don't want to trace
// a dead StackDescription.
if (mDescription) {
JS::FreeStackDescription(nullptr, mDescription);
mDescription = nullptr;
}
mozilla::DropJSObjects(this);
}
NS_INLINE_DECL_CYCLE_COLLECTING_NATIVE_REFCOUNTING(StackDescriptionOwner)
NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_NATIVE_CLASS(StackDescriptionOwner)
JS::FrameDescription& FrameAt(size_t aIndex)
{
MOZ_ASSERT(aIndex < mDescription->nframes);
return mDescription->frames[aIndex];
}
unsigned NumFrames()
{
return mDescription->nframes;
}
private:
JS::StackDescription* mDescription;
};
NS_IMPL_CYCLE_COLLECTION_ROOT_NATIVE(StackDescriptionOwner, AddRef)
NS_IMPL_CYCLE_COLLECTION_UNROOT_NATIVE(StackDescriptionOwner, Release)
NS_IMPL_CYCLE_COLLECTION_CLASS(StackDescriptionOwner)
NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(StackDescriptionOwner)
if (tmp->mDescription) {
JS::FreeStackDescription(nullptr, tmp->mDescription);
tmp->mDescription = nullptr;
}
NS_IMPL_CYCLE_COLLECTION_UNLINK_END
NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(StackDescriptionOwner)
NS_IMPL_CYCLE_COLLECTION_TRAVERSE_SCRIPT_OBJECTS
NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
NS_IMPL_CYCLE_COLLECTION_TRACE_BEGIN(StackDescriptionOwner)
JS::StackDescription* desc = tmp->mDescription;
if (tmp->mDescription) {
for (size_t i = 0; i < desc->nframes; ++i) {
NS_IMPL_CYCLE_COLLECTION_TRACE_JS_MEMBER_CALLBACK(mDescription->frames[i].markedLocation1());
NS_IMPL_CYCLE_COLLECTION_TRACE_JS_MEMBER_CALLBACK(mDescription->frames[i].markedLocation2());
}
}
NS_IMPL_CYCLE_COLLECTION_TRACE_END
class JSStackFrame : public nsIStackFrame
{
public:
NS_DECL_CYCLE_COLLECTING_ISUPPORTS
NS_DECL_CYCLE_COLLECTION_CLASS(JSStackFrame)
NS_DECL_NSISTACKFRAME
// A null aStackDescription or an aIndex that's out of range for the
// number of frames aStackDescription has will mean that the
// JSStackFrame will never look at the stack description. Instead,
// it is expected to be initialized by the caller as needed.
JSStackFrame(StackDescriptionOwner* aStackDescription, size_t aIndex);
virtual ~JSStackFrame();
static already_AddRefed<nsIStackFrame>
CreateStack(JSContext* aCx, int32_t aMaxDepth = -1);
static already_AddRefed<nsIStackFrame>
CreateStackFrameLocation(uint32_t aLanguage,
const char* aFilename,
const char* aFunctionName,
int32_t aLineNumber,
nsIStackFrame* aCaller);
private:
bool IsJSFrame() const {
return mLanguage == nsIProgrammingLanguage::JAVASCRIPT;
}
int32_t GetLineno();
nsRefPtr<StackDescriptionOwner> mStackDescription;
nsCOMPtr<nsIStackFrame> mCaller;
// Cached values
nsString mFilename;
nsString mFunname;
int32_t mLineno;
uint32_t mLanguage;
size_t mIndex;
bool mFilenameInitialized;
bool mFunnameInitialized;
bool mLinenoInitialized;
bool mCallerInitialized;
};
JSStackFrame::JSStackFrame(StackDescriptionOwner* aStackDescription,
size_t aIndex)
: mLineno(0)
{
if (aStackDescription && aIndex < aStackDescription->NumFrames()) {
mStackDescription = aStackDescription;
mIndex = aIndex;
mFilenameInitialized = false;
mFunnameInitialized = false;
mLinenoInitialized = false;
mCallerInitialized = false;
mLanguage = nsIProgrammingLanguage::JAVASCRIPT;
} else {
MOZ_ASSERT(!mStackDescription);
mIndex = 0;
mFilenameInitialized = true;
mFunnameInitialized = true;
mLinenoInitialized = true;
mCallerInitialized = true;
mLanguage = nsIProgrammingLanguage::UNKNOWN;
}
}
JSStackFrame::~JSStackFrame()
{
}
NS_IMPL_CYCLE_COLLECTION(JSStackFrame, mStackDescription, mCaller)
NS_IMPL_CYCLE_COLLECTING_ADDREF(JSStackFrame)
NS_IMPL_CYCLE_COLLECTING_RELEASE(JSStackFrame)
NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(JSStackFrame)
NS_INTERFACE_MAP_ENTRY(nsIStackFrame)
NS_INTERFACE_MAP_ENTRY(nsISupports)
NS_INTERFACE_MAP_END
/* readonly attribute uint32_t language; */
NS_IMETHODIMP JSStackFrame::GetLanguage(uint32_t* aLanguage)
{
*aLanguage = mLanguage;
return NS_OK;
}
/* readonly attribute string languageName; */
NS_IMETHODIMP JSStackFrame::GetLanguageName(nsACString& aLanguageName)
{
static const char js[] = "JavaScript";
static const char cpp[] = "C++";
if (IsJSFrame()) {
aLanguageName.AssignASCII(js);
} else {
aLanguageName.AssignASCII(cpp);
}
return NS_OK;
}
/* readonly attribute AString filename; */
NS_IMETHODIMP JSStackFrame::GetFilename(nsAString& aFilename)
{
if (!mFilenameInitialized) {
JS::FrameDescription& desc = mStackDescription->FrameAt(mIndex);
if (const char *filename = desc.filename()) {
CopyUTF8toUTF16(filename, mFilename);
}
mFilenameInitialized = true;
}
// The filename must be set to null if empty.
if (mFilename.IsEmpty()) {
aFilename.SetIsVoid(true);
} else {
aFilename.Assign(mFilename);
}
return NS_OK;
}
/* readonly attribute AString name; */
NS_IMETHODIMP JSStackFrame::GetName(nsAString& aFunction)
{
if (!mFunnameInitialized) {
JS::FrameDescription& desc = mStackDescription->FrameAt(mIndex);
if (JSFlatString *name = desc.funDisplayName()) {
mFunname.Assign(JS_GetFlatStringChars(name),
// XXXbz Can't JS_GetStringLength on JSFlatString!
JS_GetStringLength(JS_FORGET_STRING_FLATNESS(name)));
}
mFunnameInitialized = true;
}
// The function name must be set to null if empty.
if (mFunname.IsEmpty()) {
aFunction.SetIsVoid(true);
} else {
aFunction.Assign(mFunname);
}
return NS_OK;
}
int32_t
JSStackFrame::GetLineno()
{
if (!mLinenoInitialized) {
JS::FrameDescription& desc = mStackDescription->FrameAt(mIndex);
mLineno = desc.lineno();
mLinenoInitialized = true;
}
return mLineno;
}
/* readonly attribute int32_t lineNumber; */
NS_IMETHODIMP JSStackFrame::GetLineNumber(int32_t* aLineNumber)
{
*aLineNumber = GetLineno();
return NS_OK;
}
/* readonly attribute AUTF8String sourceLine; */
NS_IMETHODIMP JSStackFrame::GetSourceLine(nsACString& aSourceLine)
{
aSourceLine.Truncate();
return NS_OK;
}
/* readonly attribute nsIStackFrame caller; */
NS_IMETHODIMP JSStackFrame::GetCaller(nsIStackFrame** aCaller)
{
if (!mCallerInitialized) {
mCaller = new JSStackFrame(mStackDescription, mIndex+1);
mCallerInitialized = true;
}
NS_IF_ADDREF(*aCaller = mCaller);
return NS_OK;
}
/* AUTF8String toString (); */
NS_IMETHODIMP JSStackFrame::ToString(nsACString& _retval)
{
_retval.Truncate();
const char* frametype = IsJSFrame() ? "JS" : "native";
nsString filename;
nsresult rv = GetFilename(filename);
NS_ENSURE_SUCCESS(rv, rv);
if (filename.IsEmpty()) {
filename.AssignLiteral("<unknown filename>");
}
nsString funname;
rv = GetName(funname);
NS_ENSURE_SUCCESS(rv, rv);
if (funname.IsEmpty()) {
funname.AssignLiteral("<TOP_LEVEL>");
}
static const char format[] = "%s frame :: %s :: %s :: line %d";
_retval.AppendPrintf(format, frametype,
NS_ConvertUTF16toUTF8(filename).get(),
NS_ConvertUTF16toUTF8(funname).get(),
GetLineno());
return NS_OK;
}
/* static */ already_AddRefed<nsIStackFrame>
JSStackFrame::CreateStack(JSContext* aCx, int32_t aMaxDepth)
{
static const unsigned MAX_FRAMES = 100;
if (aMaxDepth < 0) {
aMaxDepth = MAX_FRAMES;
}
JS::StackDescription* desc = JS::DescribeStack(aCx, aMaxDepth);
if (!desc) {
return nullptr;
}
nsRefPtr<StackDescriptionOwner> descOwner = new StackDescriptionOwner(desc);
nsRefPtr<JSStackFrame> first = new JSStackFrame(descOwner, 0);
return first.forget();
}
/* static */ already_AddRefed<nsIStackFrame>
JSStackFrame::CreateStackFrameLocation(uint32_t aLanguage,
const char* aFilename,
const char* aFunctionName,
int32_t aLineNumber,
nsIStackFrame* aCaller)
{
nsRefPtr<JSStackFrame> self = new JSStackFrame(nullptr, 0);
self->mLanguage = aLanguage;
self->mLineno = aLineNumber;
CopyUTF8toUTF16(aFilename, self->mFilename);
CopyUTF8toUTF16(aFunctionName, self->mFunname);
self->mCaller = aCaller;
return self.forget();
}
already_AddRefed<nsIStackFrame>
CreateStack(JSContext* aCx, int32_t aMaxDepth)
{
return JSStackFrame::CreateStack(aCx, aMaxDepth);
}
already_AddRefed<nsIStackFrame>
CreateStackFrameLocation(uint32_t aLanguage,
const char* aFilename,
const char* aFunctionName,
int32_t aLineNumber,
nsIStackFrame* aCaller)
{
return JSStackFrame::CreateStackFrameLocation(aLanguage, aFilename,
aFunctionName, aLineNumber,
aCaller);
}
} // namespace exceptions
} // namespace dom
} // namespace mozilla