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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 */
#ifndef mozilla_nsDumpUtils_h
#define mozilla_nsDumpUtils_h
#include "nsIObserver.h"
#include "base/message_loop.h"
#include "nsXULAppAPI.h"
#include "nsThreadUtils.h"
#include "mozilla/Mutex.h"
#include "mozilla/StaticPtr.h"
#include "nsTArray.h"
#ifdef LOG
# undef LOG
#ifdef ANDROID
# include "android/log.h"
# define LOG(...) \
__android_log_print(ANDROID_LOG_INFO, "Gecko:DumpUtils", ##__VA_ARGS__)
# define LOG(...)
#ifdef XP_UNIX // {
* Abstract base class for something which watches an fd and takes action when
* we can read from it without blocking.
class FdWatcher : public MessageLoopForIO::Watcher, public nsIObserver {
MessageLoopForIO::FileDescriptorWatcher mReadWatcher;
int mFd;
virtual ~FdWatcher() {
// StopWatching should have run.
MOZ_ASSERT(mFd == -1);
FdWatcher() : mFd(-1) { MOZ_ASSERT(NS_IsMainThread()); }
* Open the fd to watch. If we encounter an error, return -1.
virtual int OpenFd() = 0;
* Called when you can read() from the fd without blocking. Note that this
* function is also called when you're at eof (read() returns 0 in this case).
virtual void OnFileCanReadWithoutBlocking(int aFd) override = 0;
virtual void OnFileCanWriteWithoutBlocking(int aFd) override{};
* Initialize this object. This should be called right after the object is
* constructed. (This would go in the constructor, except we interact with
* XPCOM, which we can't do from a constructor because our refcount is 0 at
* that point.)
void Init();
// Implementations may call this function multiple times if they ensure that
virtual void StartWatching();
// Since implementations can call StartWatching() multiple times, they can of
// course call StopWatching() multiple times.
virtual void StopWatching();
NS_IMETHOD Observe(nsISupports* aSubject, const char* aTopic,
const char16_t* aData) override {
MOZ_ASSERT(!strcmp(aTopic, "xpcom-shutdown"));
"FdWatcher::StopWatching", this, &FdWatcher::StopWatching));
return NS_OK;
typedef void (*FifoCallback)(const nsCString& aInputStr);
struct FifoInfo {
nsCString mCommand;
FifoCallback mCallback;
typedef nsTArray<FifoInfo> FifoInfoArray;
class FifoWatcher : public FdWatcher {
* The name of the preference used to enable/disable the FifoWatcher.
// The length of this array must match the size of the string constant in
// the definition in nsDumpUtils.cpp. A mismatch will result in a compile-time
// error.
static const char kPrefName[38];
static FifoWatcher* GetSingleton();
static bool MaybeCreate();
void RegisterCallback(const nsCString& aCommand, FifoCallback aCallback);
virtual ~FifoWatcher();
virtual int OpenFd() override;
virtual void OnFileCanReadWithoutBlocking(int aFd) override;
nsAutoCString mDirPath;
static mozilla::StaticRefPtr<FifoWatcher> sSingleton;
explicit FifoWatcher(nsCString aPath)
: mDirPath(aPath), mFifoInfoLock("FifoWatcher.mFifoInfoLock") {}
mozilla::Mutex mFifoInfoLock; // protects mFifoInfo
FifoInfoArray mFifoInfo;
typedef void (*PipeCallback)(const uint8_t aRecvSig);
struct SignalInfo {
uint8_t mSignal;
PipeCallback mCallback;
typedef nsTArray<SignalInfo> SignalInfoArray;
class SignalPipeWatcher : public FdWatcher {
static SignalPipeWatcher* GetSingleton();
void RegisterCallback(uint8_t aSignal, PipeCallback aCallback);
void RegisterSignalHandler(uint8_t aSignal = 0);
virtual ~SignalPipeWatcher();
virtual int OpenFd() override;
virtual void StopWatching() override;
virtual void OnFileCanReadWithoutBlocking(int aFd) override;
static mozilla::StaticRefPtr<SignalPipeWatcher> sSingleton;
SignalPipeWatcher() : mSignalInfoLock("SignalPipeWatcher.mSignalInfoLock") {
mozilla::Mutex mSignalInfoLock; // protects mSignalInfo
SignalInfoArray mSignalInfo;
#endif // XP_UNIX }
class nsDumpUtils {
* This function creates a new unique file based on |aFilename| in a
* world-readable temp directory. This is the system temp directory
* or, in the case of Android, the downloads directory. If |aFile| is
* non-null, it is assumed to point to a folder, and that folder is used
* instead.
static nsresult OpenTempFile(const nsACString& aFilename, nsIFile** aFile,
const nsACString& aFoldername = ""_ns,
Mode aMode = CREATE_UNIQUE);