The Tor Browser: dom/asmjscache/AsmJSCache.cpp@b8a032363ba2 (annotated)

dom/asmjscache/AsmJSCache.cpp@b8a032363ba2 (annotated)

dom/asmjscache/AsmJSCache.cpp

Thu, 22 Jan 2015 13:21:57 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 22 Jan 2015 13:21:57 +0100
branch: TOR_BUG_9701
changeset 15: b8a032363ba2
permissions: -rw-r--r--

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* vim: set ts=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/. */
 #include "AsmJSCache.h"
 #include <stdio.h>
 #include "js/RootingAPI.h"
 #include "jsfriendapi.h"
 #include "mozilla/Assertions.h"
 #include "mozilla/CondVar.h"
 #include "mozilla/dom/asmjscache/PAsmJSCacheEntryChild.h"
 #include "mozilla/dom/asmjscache/PAsmJSCacheEntryParent.h"
 #include "mozilla/dom/ContentChild.h"
 #include "mozilla/dom/PermissionMessageUtils.h"
 #include "mozilla/dom/quota/Client.h"
 #include "mozilla/dom/quota/OriginOrPatternString.h"
 #include "mozilla/dom/quota/QuotaManager.h"
 #include "mozilla/dom/quota/QuotaObject.h"
 #include "mozilla/dom/quota/UsageInfo.h"
 #include "mozilla/HashFunctions.h"
 #include "mozilla/unused.h"
 #include "nsIAtom.h"
 #include "nsIFile.h"
 #include "nsIPermissionManager.h"
 #include "nsIPrincipal.h"
 #include "nsIRunnable.h"
 #include "nsISimpleEnumerator.h"
 #include "nsIThread.h"
 #include "nsIXULAppInfo.h"
 #include "nsJSPrincipals.h"
 #include "nsThreadUtils.h"
 #include "nsXULAppAPI.h"
 #include "prio.h"
 #include "private/pprio.h"
 #define ASMJSCACHE_METADATA_FILE_NAME "metadata"
 #define ASMJSCACHE_ENTRY_FILE_NAME_BASE "module"
 using mozilla::dom::quota::AssertIsOnIOThread;
 using mozilla::dom::quota::OriginOrPatternString;
 using mozilla::dom::quota::PersistenceType;
 using mozilla::dom::quota::QuotaManager;
 using mozilla::dom::quota::QuotaObject;
 using mozilla::dom::quota::UsageInfo;
 using mozilla::unused;
 using mozilla::HashString;
 namespace mozilla {
 MOZ_TYPE_SPECIFIC_SCOPED_POINTER_TEMPLATE(ScopedPRFileDesc, PRFileDesc, PR_Close);
 namespace dom {
 namespace asmjscache {
 namespace {
 bool
 IsMainProcess()
 {
   return XRE_GetProcessType() == GeckoProcessType_Default;
 }
 // Anything smaller should compile fast enough that caching will just add
 // overhead.
 static const size_t sMinCachedModuleLength = 10000;
 // The number of characters to hash into the Metadata::Entry::mFastHash.
 static const unsigned sNumFastHashChars = 4096;
 nsresult
 WriteMetadataFile(nsIFile* aMetadataFile, const Metadata& aMetadata)
 {
   int32_t openFlags = PR_WRONLY | PR_TRUNCATE | PR_CREATE_FILE;
   JS::BuildIdCharVector buildId;
   bool ok = GetBuildId(&buildId);
   NS_ENSURE_TRUE(ok, NS_ERROR_OUT_OF_MEMORY);
   ScopedPRFileDesc fd;
   nsresult rv = aMetadataFile->OpenNSPRFileDesc(openFlags, 0644, &fd.rwget());
   NS_ENSURE_SUCCESS(rv, rv);
   uint32_t length = buildId.length();
   int32_t bytesWritten = PR_Write(fd, &length, sizeof(length));
   NS_ENSURE_TRUE(bytesWritten == sizeof(length), NS_ERROR_UNEXPECTED);
   bytesWritten = PR_Write(fd, buildId.begin(), length);
   NS_ENSURE_TRUE(bytesWritten == int32_t(length), NS_ERROR_UNEXPECTED);
   bytesWritten = PR_Write(fd, &aMetadata, sizeof(aMetadata));
   NS_ENSURE_TRUE(bytesWritten == sizeof(aMetadata), NS_ERROR_UNEXPECTED);
   return NS_OK;
 }
 nsresult
 ReadMetadataFile(nsIFile* aMetadataFile, Metadata& aMetadata)
 {
   int32_t openFlags = PR_RDONLY;
   ScopedPRFileDesc fd;
   nsresult rv = aMetadataFile->OpenNSPRFileDesc(openFlags, 0644, &fd.rwget());
   NS_ENSURE_SUCCESS(rv, rv);
   // Read the buildid and check that it matches the current buildid
   JS::BuildIdCharVector currentBuildId;
   bool ok = GetBuildId(&currentBuildId);
   NS_ENSURE_TRUE(ok, NS_ERROR_OUT_OF_MEMORY);
   uint32_t length;
   int32_t bytesRead = PR_Read(fd, &length, sizeof(length));
   NS_ENSURE_TRUE(bytesRead == sizeof(length), NS_ERROR_UNEXPECTED);
   NS_ENSURE_TRUE(currentBuildId.length() == length, NS_ERROR_UNEXPECTED);
   JS::BuildIdCharVector fileBuildId;
   ok = fileBuildId.resize(length);
   NS_ENSURE_TRUE(ok, NS_ERROR_OUT_OF_MEMORY);
   bytesRead = PR_Read(fd, fileBuildId.begin(), length);
   NS_ENSURE_TRUE(bytesRead == int32_t(length), NS_ERROR_UNEXPECTED);
   for (uint32_t i = 0; i < length; i++) {
     if (currentBuildId[i] != fileBuildId[i]) {
       return NS_ERROR_FAILURE;
     }
   }
   // Read the Metadata struct
   bytesRead = PR_Read(fd, &aMetadata, sizeof(aMetadata));
   NS_ENSURE_TRUE(bytesRead == sizeof(aMetadata), NS_ERROR_UNEXPECTED);
   return NS_OK;
 }
 nsresult
 GetCacheFile(nsIFile* aDirectory, unsigned aModuleIndex, nsIFile** aCacheFile)
 {
   nsCOMPtr<nsIFile> cacheFile;
   nsresult rv = aDirectory->Clone(getter_AddRefs(cacheFile));
   NS_ENSURE_SUCCESS(rv, rv);
   nsString cacheFileName = NS_LITERAL_STRING(ASMJSCACHE_ENTRY_FILE_NAME_BASE);
   cacheFileName.AppendInt(aModuleIndex);
   rv = cacheFile->Append(cacheFileName);
   NS_ENSURE_SUCCESS(rv, rv);
   cacheFile.forget(aCacheFile);
   return NS_OK;
 }
 class AutoDecreaseUsageForOrigin
 {
   const nsACString& mGroup;
   const nsACString& mOrigin;
 public:
   uint64_t mFreed;
   AutoDecreaseUsageForOrigin(const nsACString& aGroup,
                              const nsACString& aOrigin)
   : mGroup(aGroup),
     mOrigin(aOrigin),
     mFreed(0)
   { }
   ~AutoDecreaseUsageForOrigin()
   {
     AssertIsOnIOThread();
     if (!mFreed) {
       return;
     }
     QuotaManager* qm = QuotaManager::Get();
     MOZ_ASSERT(qm, "We are on the QuotaManager's IO thread");
     qm->DecreaseUsageForOrigin(quota::PERSISTENCE_TYPE_TEMPORARY,
                                mGroup, mOrigin, mFreed);
   }
 };
 static void
 EvictEntries(nsIFile* aDirectory, const nsACString& aGroup,
              const nsACString& aOrigin, uint64_t aNumBytes,
              Metadata& aMetadata)
 {
   AssertIsOnIOThread();
   AutoDecreaseUsageForOrigin usage(aGroup, aOrigin);
   for (int i = Metadata::kLastEntry; i >= 0 && usage.mFreed < aNumBytes; i--) {
     Metadata::Entry& entry = aMetadata.mEntries[i];
     unsigned moduleIndex = entry.mModuleIndex;
     nsCOMPtr<nsIFile> file;
     nsresult rv = GetCacheFile(aDirectory, moduleIndex, getter_AddRefs(file));
     if (NS_WARN_IF(NS_FAILED(rv))) {
       return;
     }
     bool exists;
     rv = file->Exists(&exists);
     if (NS_WARN_IF(NS_FAILED(rv))) {
       return;
     }
     if (exists) {
       int64_t fileSize;
       rv = file->GetFileSize(&fileSize);
       if (NS_WARN_IF(NS_FAILED(rv))) {
         return;
       }
       rv = file->Remove(false);
       if (NS_WARN_IF(NS_FAILED(rv))) {
         return;
       }
       usage.mFreed += fileSize;
     }
     entry.clear();
   }
 }
 // FileDescriptorHolder owns a file descriptor and its memory mapping.
 // FileDescriptorHolder is derived by all three runnable classes (that is,
 // (Single|Parent|Child)ProcessRunnable. To avoid awkward workarouds,
 // FileDescriptorHolder is derived virtually by File and MainProcessRunnable for
 // the benefit of SingleProcessRunnable, which derives both. Since File and
 // MainProcessRunnable both need to be runnables, FileDescriptorHolder also
 // derives nsRunnable.
 class FileDescriptorHolder : public nsRunnable
 {
 public:
   FileDescriptorHolder()
   : mQuotaObject(nullptr),
     mFileSize(INT64_MIN),
     mFileDesc(nullptr),
     mFileMap(nullptr),
     mMappedMemory(nullptr)
   { }
   ~FileDescriptorHolder()
   {
     // These resources should have already been released by Finish().
     MOZ_ASSERT(!mQuotaObject);
     MOZ_ASSERT(!mMappedMemory);
     MOZ_ASSERT(!mFileMap);
     MOZ_ASSERT(!mFileDesc);
   }
   size_t
   FileSize() const
   {
     MOZ_ASSERT(mFileSize >= 0, "Accessing FileSize of unopened file");
     return mFileSize;
   }
   PRFileDesc*
   FileDesc() const
   {
     MOZ_ASSERT(mFileDesc, "Accessing FileDesc of unopened file");
     return mFileDesc;
   }
   bool
   MapMemory(OpenMode aOpenMode)
   {
     MOZ_ASSERT(!mFileMap, "Cannot call MapMemory twice");
     PRFileMapProtect mapFlags = aOpenMode == eOpenForRead ? PR_PROT_READONLY
                                                           : PR_PROT_READWRITE;
     mFileMap = PR_CreateFileMap(mFileDesc, mFileSize, mapFlags);
     NS_ENSURE_TRUE(mFileMap, false);
     mMappedMemory = PR_MemMap(mFileMap, 0, mFileSize);
     NS_ENSURE_TRUE(mMappedMemory, false);
     return true;
   }
   void*
   MappedMemory() const
   {
     MOZ_ASSERT(mMappedMemory, "Accessing MappedMemory of un-mapped file");
     return mMappedMemory;
   }
 protected:
   // This method must be called before AllowNextSynchronizedOp (which releases
   // the lock protecting these resources). It is idempotent, so it is ok to call
   // multiple times (or before the file has been fully opened).
   void
   Finish()
   {
     if (mMappedMemory) {
       PR_MemUnmap(mMappedMemory, mFileSize);
       mMappedMemory = nullptr;
     }
     if (mFileMap) {
       PR_CloseFileMap(mFileMap);
       mFileMap = nullptr;
     }
     if (mFileDesc) {
       PR_Close(mFileDesc);
       mFileDesc = nullptr;
     }
     // Holding the QuotaObject alive until all the cache files are closed enables
     // assertions in QuotaManager that the cache entry isn't cleared while we
     // are working on it.
     mQuotaObject = nullptr;
   }
   nsRefPtr<QuotaObject> mQuotaObject;
   int64_t mFileSize;
   PRFileDesc* mFileDesc;
   PRFileMap* mFileMap;
   void* mMappedMemory;
 };
 // File is a base class shared by (Single|Client)ProcessEntryRunnable that
 // presents a single interface to the AsmJSCache ops which need to wait until
 // the file is open, regardless of whether we are executing in the main process
 // or not.
 class File : public virtual FileDescriptorHolder
 {
 public:
   class AutoClose
   {
     File* mFile;
   public:
     explicit AutoClose(File* aFile = nullptr)
     : mFile(aFile)
     { }
     void
     Init(File* aFile)
     {
       MOZ_ASSERT(!mFile);
       mFile = aFile;
     }
     File*
     operator->() const
     {
       MOZ_ASSERT(mFile);
       return mFile;
     }
     void
     Forget(File** aFile)
     {
       *aFile = mFile;
       mFile = nullptr;
     }
     ~AutoClose()
     {
       if (mFile) {
         mFile->Close();
       }
     }
   };
   bool
   BlockUntilOpen(AutoClose* aCloser)
   {
     MOZ_ASSERT(!mWaiting, "Can only call BlockUntilOpen once");
     MOZ_ASSERT(!mOpened, "Can only call BlockUntilOpen once");
     mWaiting = true;
     nsresult rv = NS_DispatchToMainThread(this);
     NS_ENSURE_SUCCESS(rv, false);
     {
       MutexAutoLock lock(mMutex);
       while (mWaiting) {
         mCondVar.Wait();
       }
     }
     if (!mOpened) {
       return false;
     }
     // Now that we're open, we're guarnateed a Close() call. However, we are
     // not guarnateed someone is holding an outstanding reference until the File
     // is closed, so we do that ourselves and Release() in OnClose().
     aCloser->Init(this);
     AddRef();
     return true;
   }
   // This method must be called if BlockUntilOpen returns 'true'. AutoClose
   // mostly takes care of this. A derived class that implements Close() must
   // guarnatee that OnClose() is called (eventually).
   virtual void
   Close() = 0;
 protected:
   File()
   : mMutex("File::mMutex"),
     mCondVar(mMutex, "File::mCondVar"),
     mWaiting(false),
     mOpened(false)
   { }
   ~File()
   {
     MOZ_ASSERT(!mWaiting, "Shouldn't be destroyed while thread is waiting");
     MOZ_ASSERT(!mOpened, "OnClose() should have been called");
   }
   void
   OnOpen()
   {
     Notify(true);
   }
   void
   OnFailure()
   {
     FileDescriptorHolder::Finish();
     Notify(false);
   }
   void
   OnClose()
   {
     FileDescriptorHolder::Finish();
     MOZ_ASSERT(mOpened);
     mOpened = false;
     // Match the AddRef in BlockUntilOpen(). The main thread event loop still
     // holds an outstanding ref which will keep 'this' alive until returning to
     // the event loop.
     Release();
   }
 private:
   void
   Notify(bool aSuccess)
   {
     MOZ_ASSERT(NS_IsMainThread());
     MutexAutoLock lock(mMutex);
     MOZ_ASSERT(mWaiting);
     mWaiting = false;
     mOpened = aSuccess;
     mCondVar.Notify();
   }
   Mutex mMutex;
   CondVar mCondVar;
   bool mWaiting;
   bool mOpened;
 };
 // MainProcessRunnable is a base class shared by (Single|Parent)ProcessRunnable
 // that factors out the runnable state machine required to open a cache entry
 // that runs in the main process.
 class MainProcessRunnable : public virtual FileDescriptorHolder
 {
 public:
   NS_DECL_NSIRUNNABLE
   // MainProcessRunnable runnable assumes that the derived class ensures
   // (through ref-counting or preconditions) that aPrincipal is kept alive for
   // the lifetime of the MainProcessRunnable.
   MainProcessRunnable(nsIPrincipal* aPrincipal,
                       OpenMode aOpenMode,
                       WriteParams aWriteParams)
   : mPrincipal(aPrincipal),
     mOpenMode(aOpenMode),
     mWriteParams(aWriteParams),
     mNeedAllowNextSynchronizedOp(false),
     mPersistence(quota::PERSISTENCE_TYPE_INVALID),
     mState(eInitial)
   {
     MOZ_ASSERT(IsMainProcess());
   }
   virtual ~MainProcessRunnable()
   {
     MOZ_ASSERT(mState == eFinished);
     MOZ_ASSERT(!mNeedAllowNextSynchronizedOp);
   }
 protected:
   // This method is called by the derived class on the main thread when a
   // cache entry has been selected to open.
   void
   OpenForRead(unsigned aModuleIndex)
   {
     MOZ_ASSERT(NS_IsMainThread());
     MOZ_ASSERT(mState == eWaitingToOpenCacheFileForRead);
     MOZ_ASSERT(mOpenMode == eOpenForRead);
     mModuleIndex = aModuleIndex;
     mState = eReadyToOpenCacheFileForRead;
     DispatchToIOThread();
   }
   // This method is called by the derived class on the main thread when no cache
   // entry was found to open. If we just tried a lookup in persistent storage
   // then we might still get a hit in temporary storage (for an asm.js module
   // that wasn't compiled at install-time).
   void
   CacheMiss()
   {
     MOZ_ASSERT(NS_IsMainThread());
     MOZ_ASSERT(mState == eFailedToReadMetadata ||
                mState == eWaitingToOpenCacheFileForRead);
     MOZ_ASSERT(mOpenMode == eOpenForRead);
     if (mPersistence == quota::PERSISTENCE_TYPE_TEMPORARY) {
       Fail();
       return;
     }
     // Try again with a clean slate. InitOnMainThread will see that mPersistence
     // is initialized and switch to temporary storage.
     MOZ_ASSERT(mPersistence == quota::PERSISTENCE_TYPE_PERSISTENT);
     FinishOnMainThread();
     mState = eInitial;
     NS_DispatchToMainThread(this);
   }
   // This method is called by the derived class (either on the JS compilation
   // thread or the main thread) when the JS engine is finished reading/writing
   // the cache entry.
   void
   Close()
   {
     MOZ_ASSERT(mState == eOpened);
     mState = eClosing;
     NS_DispatchToMainThread(this);
   }
   // This method is called both internally and by derived classes upon any
   // failure that prevents the eventual opening of the cache entry.
   void
   Fail()
   {
     MOZ_ASSERT(mState != eOpened &&
                mState != eClosing &&
                mState != eFailing &&
                mState != eFinished);
     mState = eFailing;
     NS_DispatchToMainThread(this);
   }
   // Called by MainProcessRunnable on the main thread after metadata is open:
   virtual void
   OnOpenMetadataForRead(const Metadata& aMetadata) = 0;
   // Called by MainProcessRunnable on the main thread after the entry is open:
   virtual void
   OnOpenCacheFile() = 0;
   // This method may be overridden, but it must be called from the overrider.
   // Called by MainProcessRunnable on the main thread after a call to Fail():
   virtual void
   OnFailure()
   {
     FinishOnMainThread();
   }
   // This method may be overridden, but it must be called from the overrider.
   // Called by MainProcessRunnable on the main thread after a call to Close():
   virtual void
   OnClose()
   {
     FinishOnMainThread();
   }
 private:
   nsresult
   InitOnMainThread();
   nsresult
   ReadMetadata();
   nsresult
   OpenCacheFileForWrite();
   nsresult
   OpenCacheFileForRead();
   void
   FinishOnMainThread();
   void
   DispatchToIOThread()
   {
     // If shutdown just started, the QuotaManager may have been deleted.
     QuotaManager* qm = QuotaManager::Get();
     if (!qm) {
       Fail();
       return;
     }
     nsresult rv = qm->IOThread()->Dispatch(this, NS_DISPATCH_NORMAL);
     if (NS_FAILED(rv)) {
       Fail();
       return;
     }
   }
   nsIPrincipal* const mPrincipal;
   const OpenMode mOpenMode;
   const WriteParams mWriteParams;
   // State initialized during eInitial:
   bool mNeedAllowNextSynchronizedOp;
   quota::PersistenceType mPersistence;
   nsCString mGroup;
   nsCString mOrigin;
   nsCString mStorageId;
   // State initialized during eReadyToReadMetadata
   nsCOMPtr<nsIFile> mDirectory;
   nsCOMPtr<nsIFile> mMetadataFile;
   Metadata mMetadata;
   // State initialized during eWaitingToOpenCacheFileForRead
   unsigned mModuleIndex;
   enum State {
     eInitial, // Just created, waiting to be dispatched to main thread
     eWaitingToOpenMetadata, // Waiting to be called back from WaitForOpenAllowed
     eReadyToReadMetadata, // Waiting to read the metadata file on the IO thread
     eFailedToReadMetadata, // Waiting to be dispatched to main thread after fail
     eSendingMetadataForRead, // Waiting to send OnOpenMetadataForRead
     eWaitingToOpenCacheFileForRead, // Waiting to hear back from child
     eReadyToOpenCacheFileForRead, // Waiting to open cache file for read
     eSendingCacheFile, // Waiting to send OnOpenCacheFile on the main thread
     eOpened, // Finished calling OnOpen, waiting to be closed
     eClosing, // Waiting to be dispatched to main thread again
     eFailing, // Just failed, waiting to be dispatched to the main thread
     eFinished, // Terminal state
   };
   State mState;
 };
 nsresult
 MainProcessRunnable::InitOnMainThread()
 {
   MOZ_ASSERT(NS_IsMainThread());
   MOZ_ASSERT(mState == eInitial);
   QuotaManager* qm = QuotaManager::GetOrCreate();
   NS_ENSURE_STATE(qm);
   nsresult rv = QuotaManager::GetInfoFromPrincipal(mPrincipal, &mGroup,
                                                    &mOrigin, nullptr, nullptr);
   NS_ENSURE_SUCCESS(rv, rv);
   bool isApp = mPrincipal->GetAppStatus() !=
                nsIPrincipal::APP_STATUS_NOT_INSTALLED;
   if (mOpenMode == eOpenForWrite) {
     MOZ_ASSERT(mPersistence == quota::PERSISTENCE_TYPE_INVALID);
     if (mWriteParams.mInstalled) {
       // If we are performing install-time caching of an app, we'd like to store
       // the cache entry in persistent storage so the entry is never evicted,
       // but we need to verify that the app has unlimited storage permissions
       // first. Unlimited storage permissions justify us in skipping all quota
       // checks when storing the cache entry and avoids all the issues around
       // the persistent quota prompt.
       MOZ_ASSERT(isApp);
       nsCOMPtr<nsIPermissionManager> pm =
         do_GetService(NS_PERMISSIONMANAGER_CONTRACTID);
       NS_ENSURE_TRUE(pm, NS_ERROR_UNEXPECTED);
       uint32_t permission;
       rv = pm->TestPermissionFromPrincipal(mPrincipal,
                                            PERMISSION_STORAGE_UNLIMITED,
                                            &permission);
       NS_ENSURE_SUCCESS(rv, NS_ERROR_UNEXPECTED);
       // If app doens't have the unlimited storage permission, we can still
       // cache in temporary for a likely good first-run experience.
       mPersistence = permission == nsIPermissionManager::ALLOW_ACTION
                      ? quota::PERSISTENCE_TYPE_PERSISTENT
                      : quota::PERSISTENCE_TYPE_TEMPORARY;
     } else {
       mPersistence = quota::PERSISTENCE_TYPE_TEMPORARY;
     }
   } else {
     // For the reasons described above, apps may have cache entries in both
     // persistent and temporary storage. At lookup time we don't know how and
     // where the given script was cached, so start the search in persistent
     // storage and, if that fails, search in temporary storage. (Non-apps can
     // only be stored in temporary storage.)
     if (mPersistence == quota::PERSISTENCE_TYPE_INVALID) {
       mPersistence = isApp ? quota::PERSISTENCE_TYPE_PERSISTENT
                            : quota::PERSISTENCE_TYPE_TEMPORARY;
     } else {
       MOZ_ASSERT(isApp);
       MOZ_ASSERT(mPersistence == quota::PERSISTENCE_TYPE_PERSISTENT);
       mPersistence = quota::PERSISTENCE_TYPE_TEMPORARY;
     }
   }
   QuotaManager::GetStorageId(mPersistence, mOrigin, quota::Client::ASMJS,
                              NS_LITERAL_STRING("asmjs"), mStorageId);
   return NS_OK;
 }
 nsresult
 MainProcessRunnable::ReadMetadata()
 {
   AssertIsOnIOThread();
   MOZ_ASSERT(mState == eReadyToReadMetadata);
   QuotaManager* qm = QuotaManager::Get();
   MOZ_ASSERT(qm, "We are on the QuotaManager's IO thread");
   // Only track quota for temporary storage. For persistent storage, we've
   // already checked that we have unlimited-storage permissions.
   bool trackQuota = mPersistence == quota::PERSISTENCE_TYPE_TEMPORARY;
   nsresult rv = qm->EnsureOriginIsInitialized(mPersistence, mGroup, mOrigin,
                                               trackQuota,
                                               getter_AddRefs(mDirectory));
   NS_ENSURE_SUCCESS(rv, rv);
   rv = mDirectory->Append(NS_LITERAL_STRING(ASMJSCACHE_DIRECTORY_NAME));
   NS_ENSURE_SUCCESS(rv, rv);
   bool exists;
   rv = mDirectory->Exists(&exists);
   NS_ENSURE_SUCCESS(rv, rv);
   if (!exists) {
     rv = mDirectory->Create(nsIFile::DIRECTORY_TYPE, 0755);
     NS_ENSURE_SUCCESS(rv, rv);
   } else {
     DebugOnly<bool> isDirectory;
     MOZ_ASSERT(NS_SUCCEEDED(mDirectory->IsDirectory(&isDirectory)));
     MOZ_ASSERT(isDirectory, "Should have caught this earlier!");
   }
   rv = mDirectory->Clone(getter_AddRefs(mMetadataFile));
   NS_ENSURE_SUCCESS(rv, rv);
   rv = mMetadataFile->Append(NS_LITERAL_STRING(ASMJSCACHE_METADATA_FILE_NAME));
   NS_ENSURE_SUCCESS(rv, rv);
   rv = mMetadataFile->Exists(&exists);
   NS_ENSURE_SUCCESS(rv, rv);
   if (exists && NS_FAILED(ReadMetadataFile(mMetadataFile, mMetadata))) {
     exists = false;
   }
   if (!exists) {
     // If we are reading, we can't possibly have a cache hit.
     if (mOpenMode == eOpenForRead) {
       return NS_ERROR_FILE_NOT_FOUND;
     }
     // Initialize Metadata with a valid empty state for the LRU cache.
     for (unsigned i = 0; i < Metadata::kNumEntries; i++) {
       Metadata::Entry& entry = mMetadata.mEntries[i];
       entry.mModuleIndex = i;
       entry.clear();
     }
   }
   return NS_OK;
 }
 nsresult
 MainProcessRunnable::OpenCacheFileForWrite()
 {
   AssertIsOnIOThread();
   MOZ_ASSERT(mState == eReadyToReadMetadata);
   MOZ_ASSERT(mOpenMode == eOpenForWrite);
   mFileSize = mWriteParams.mSize;
   // Kick out the oldest entry in the LRU queue in the metadata.
   mModuleIndex = mMetadata.mEntries[Metadata::kLastEntry].mModuleIndex;
   nsCOMPtr<nsIFile> file;
   nsresult rv = GetCacheFile(mDirectory, mModuleIndex, getter_AddRefs(file));
   NS_ENSURE_SUCCESS(rv, rv);
   QuotaManager* qm = QuotaManager::Get();
   MOZ_ASSERT(qm, "We are on the QuotaManager's IO thread");
   // If we are allocating in temporary storage, ask the QuotaManager if we're
   // within the quota. If we are allocating in persistent storage, we've already
   // checked that we have the unlimited-storage permission, so there is nothing
   // to check.
   if (mPersistence == quota::PERSISTENCE_TYPE_TEMPORARY) {
     // Create the QuotaObject before all file IO and keep it alive until caching
     // completes to get maximum assertion coverage in QuotaManager against
     // concurrent removal, etc.
     mQuotaObject = qm->GetQuotaObject(mPersistence, mGroup, mOrigin, file);
     NS_ENSURE_STATE(mQuotaObject);
     if (!mQuotaObject->MaybeAllocateMoreSpace(0, mWriteParams.mSize)) {
       // If the request fails, it might be because mOrigin is using too much
       // space (MaybeAllocateMoreSpace will not evict our own origin since it is
       // active). Try to make some space by evicting LRU entries until there is
       // enough space.
       EvictEntries(mDirectory, mGroup, mOrigin, mWriteParams.mSize, mMetadata);
       if (!mQuotaObject->MaybeAllocateMoreSpace(0, mWriteParams.mSize)) {
         return NS_ERROR_FAILURE;
       }
     }
   }
   int32_t openFlags = PR_RDWR | PR_TRUNCATE | PR_CREATE_FILE;
   rv = file->OpenNSPRFileDesc(openFlags, 0644, &mFileDesc);
   NS_ENSURE_SUCCESS(rv, rv);
   // Move the mModuleIndex's LRU entry to the recent end of the queue.
   PodMove(mMetadata.mEntries + 1, mMetadata.mEntries, Metadata::kLastEntry);
   Metadata::Entry& entry = mMetadata.mEntries[0];
   entry.mFastHash = mWriteParams.mFastHash;
   entry.mNumChars = mWriteParams.mNumChars;
   entry.mFullHash = mWriteParams.mFullHash;
   entry.mModuleIndex = mModuleIndex;
   rv = WriteMetadataFile(mMetadataFile, mMetadata);
   NS_ENSURE_SUCCESS(rv, rv);
   return NS_OK;
 }
 nsresult
 MainProcessRunnable::OpenCacheFileForRead()
 {
   AssertIsOnIOThread();
   MOZ_ASSERT(mState == eReadyToOpenCacheFileForRead);
   MOZ_ASSERT(mOpenMode == eOpenForRead);
   nsCOMPtr<nsIFile> file;
   nsresult rv = GetCacheFile(mDirectory, mModuleIndex, getter_AddRefs(file));
   NS_ENSURE_SUCCESS(rv, rv);
   QuotaManager* qm = QuotaManager::Get();
   MOZ_ASSERT(qm, "We are on the QuotaManager's IO thread");
   if (mPersistence == quota::PERSISTENCE_TYPE_TEMPORARY) {
     // Even though it's not strictly necessary, create the QuotaObject before
     // all file IO and keep it alive until caching completes to get maximum
     // assertion coverage in QuotaManager against concurrent removal, etc.
     mQuotaObject = qm->GetQuotaObject(mPersistence, mGroup, mOrigin, file);
     NS_ENSURE_STATE(mQuotaObject);
   }
   rv = file->GetFileSize(&mFileSize);
   NS_ENSURE_SUCCESS(rv, rv);
   int32_t openFlags = PR_RDONLY | nsIFile::OS_READAHEAD;
   rv = file->OpenNSPRFileDesc(openFlags, 0644, &mFileDesc);
   NS_ENSURE_SUCCESS(rv, rv);
   // Move the mModuleIndex's LRU entry to the recent end of the queue.
   unsigned lruIndex = 0;
   while (mMetadata.mEntries[lruIndex].mModuleIndex != mModuleIndex) {
     if (++lruIndex == Metadata::kNumEntries) {
       return NS_ERROR_UNEXPECTED;
     }
   }
   Metadata::Entry entry = mMetadata.mEntries[lruIndex];
   PodMove(mMetadata.mEntries + 1, mMetadata.mEntries, lruIndex);
   mMetadata.mEntries[0] = entry;
   rv = WriteMetadataFile(mMetadataFile, mMetadata);
   NS_ENSURE_SUCCESS(rv, rv);
   return NS_OK;
 }
 void
 MainProcessRunnable::FinishOnMainThread()
 {
   MOZ_ASSERT(NS_IsMainThread());
   // Per FileDescriptorHolder::Finish()'s comment, call before
   // AllowNextSynchronizedOp.
   FileDescriptorHolder::Finish();
   if (mNeedAllowNextSynchronizedOp) {
     mNeedAllowNextSynchronizedOp = false;
     QuotaManager* qm = QuotaManager::Get();
     if (qm) {
       qm->AllowNextSynchronizedOp(OriginOrPatternString::FromOrigin(mOrigin),
                                   Nullable<PersistenceType>(mPersistence),
                                   mStorageId);
     }
   }
 }
 NS_IMETHODIMP
 MainProcessRunnable::Run()
 {
   nsresult rv;
   // All success/failure paths must eventually call Finish() to avoid leaving
   // the parser hanging.
   switch (mState) {
     case eInitial: {
       MOZ_ASSERT(NS_IsMainThread());
       rv = InitOnMainThread();
       if (NS_FAILED(rv)) {
         Fail();
         return NS_OK;
       }
       mState = eWaitingToOpenMetadata;
       rv = QuotaManager::Get()->WaitForOpenAllowed(
                                      OriginOrPatternString::FromOrigin(mOrigin),
                                      Nullable<PersistenceType>(mPersistence),
                                      mStorageId, this);
       if (NS_FAILED(rv)) {
         Fail();
         return NS_OK;
       }
       mNeedAllowNextSynchronizedOp = true;
       return NS_OK;
     }
     case eWaitingToOpenMetadata: {
       MOZ_ASSERT(NS_IsMainThread());
       mState = eReadyToReadMetadata;
       DispatchToIOThread();
       return NS_OK;
     }
     case eReadyToReadMetadata: {
       AssertIsOnIOThread();
       rv = ReadMetadata();
       if (NS_FAILED(rv)) {
         mState = eFailedToReadMetadata;
         NS_DispatchToMainThread(this);
         return NS_OK;
       }
       if (mOpenMode == eOpenForRead) {
         mState = eSendingMetadataForRead;
         NS_DispatchToMainThread(this);
         return NS_OK;
       }
       rv = OpenCacheFileForWrite();
       if (NS_FAILED(rv)) {
         Fail();
         return NS_OK;
       }
       mState = eSendingCacheFile;
       NS_DispatchToMainThread(this);
       return NS_OK;
     }
     case eFailedToReadMetadata: {
       MOZ_ASSERT(NS_IsMainThread());
       CacheMiss();
       return NS_OK;
     }
     case eSendingMetadataForRead: {
       MOZ_ASSERT(NS_IsMainThread());
       MOZ_ASSERT(mOpenMode == eOpenForRead);
       mState = eWaitingToOpenCacheFileForRead;
       OnOpenMetadataForRead(mMetadata);
       return NS_OK;
     }
     case eReadyToOpenCacheFileForRead: {
       AssertIsOnIOThread();
       MOZ_ASSERT(mOpenMode == eOpenForRead);
       rv = OpenCacheFileForRead();
       if (NS_FAILED(rv)) {
         Fail();
         return NS_OK;
       }
       mState = eSendingCacheFile;
       NS_DispatchToMainThread(this);
       return NS_OK;
     }
     case eSendingCacheFile: {
       MOZ_ASSERT(NS_IsMainThread());
       mState = eOpened;
       OnOpenCacheFile();
       return NS_OK;
     }
     case eFailing: {
       MOZ_ASSERT(NS_IsMainThread());
       mState = eFinished;
       OnFailure();
       return NS_OK;
     }
     case eClosing: {
       MOZ_ASSERT(NS_IsMainThread());
       mState = eFinished;
       OnClose();
       return NS_OK;
     }
     case eWaitingToOpenCacheFileForRead:
     case eOpened:
     case eFinished: {
       MOZ_ASSUME_UNREACHABLE("Shouldn't Run() in this state");
     }
   }
   MOZ_ASSUME_UNREACHABLE("Corrupt state");
   return NS_OK;
 }
 bool
 FindHashMatch(const Metadata& aMetadata, const ReadParams& aReadParams,
               unsigned* aModuleIndex)
 {
   // Perform a fast hash of the first sNumFastHashChars chars. Each cache entry
   // also stores an mFastHash of its first sNumFastHashChars so this gives us a
   // fast way to probabilistically determine whether we have a cache hit. We
   // still do a full hash of all the chars before returning the cache file to
   // the engine to avoid penalizing the case where there are multiple cached
   // asm.js modules where the first sNumFastHashChars are the same. The
   // mFullHash of each cache entry can have a different mNumChars so the fast
   // hash allows us to avoid performing up to Metadata::kNumEntries separate
   // full hashes.
   uint32_t numChars = aReadParams.mLimit - aReadParams.mBegin;
   MOZ_ASSERT(numChars > sNumFastHashChars);
   uint32_t fastHash = HashString(aReadParams.mBegin, sNumFastHashChars);
   for (unsigned i = 0; i < Metadata::kNumEntries ; i++) {
     // Compare the "fast hash" first to see whether it is worthwhile to
     // hash all the chars.
     Metadata::Entry entry = aMetadata.mEntries[i];
     if (entry.mFastHash != fastHash) {
       continue;
     }
     // Assuming we have enough characters, hash all the chars it would take
     // to match this cache entry and compare to the cache entry. If we get a
     // hit we'll still do a full source match later (in the JS engine), but
     // the full hash match means this is probably the cache entry we want.
     if (numChars < entry.mNumChars) {
       continue;
     }
     uint32_t fullHash = HashString(aReadParams.mBegin, entry.mNumChars);
     if (entry.mFullHash != fullHash) {
       continue;
     }
     *aModuleIndex = entry.mModuleIndex;
     return true;
   }
   return false;
 }
 // A runnable that executes for a cache access originating in the main process.
 class SingleProcessRunnable MOZ_FINAL : public File,
                                         private MainProcessRunnable
 {
 public:
   // In the single-process case, the calling JS compilation thread holds the
   // nsIPrincipal alive indirectly (via the global object -> compartment ->
   // principal) so we don't have to ref-count it here. This is fortunate since
   // we are off the main thread and nsIPrincipals can only be ref-counted on
   // the main thread.
   SingleProcessRunnable(nsIPrincipal* aPrincipal,
                         OpenMode aOpenMode,
                         WriteParams aWriteParams,
                         ReadParams aReadParams)
   : MainProcessRunnable(aPrincipal, aOpenMode, aWriteParams),
     mReadParams(aReadParams)
   {
     MOZ_ASSERT(IsMainProcess());
     MOZ_ASSERT(!NS_IsMainThread());
     MOZ_COUNT_CTOR(SingleProcessRunnable);
   }
   ~SingleProcessRunnable()
   {
     MOZ_COUNT_DTOR(SingleProcessRunnable);
   }
 private:
   void
   OnOpenMetadataForRead(const Metadata& aMetadata) MOZ_OVERRIDE
   {
     uint32_t moduleIndex;
     if (FindHashMatch(aMetadata, mReadParams, &moduleIndex)) {
       MainProcessRunnable::OpenForRead(moduleIndex);
     } else {
       MainProcessRunnable::CacheMiss();
     }
   }
   void
   OnOpenCacheFile() MOZ_OVERRIDE
   {
     File::OnOpen();
   }
   void
   Close() MOZ_OVERRIDE MOZ_FINAL
   {
     MainProcessRunnable::Close();
   }
   void
   OnFailure() MOZ_OVERRIDE
   {
     MainProcessRunnable::OnFailure();
     File::OnFailure();
   }
   void
   OnClose() MOZ_OVERRIDE MOZ_FINAL
   {
     MainProcessRunnable::OnClose();
     File::OnClose();
   }
   // Avoid MSVC 'dominance' warning by having clear Run() override.
   NS_IMETHODIMP
   Run() MOZ_OVERRIDE
   {
     return MainProcessRunnable::Run();
   }
   ReadParams mReadParams;
 };
 // A runnable that executes in a parent process for a cache access originating
 // in the content process. This runnable gets registered as an IPDL subprotocol
 // actor so that it can communicate with the corresponding ChildProcessRunnable.
 class ParentProcessRunnable MOZ_FINAL : public PAsmJSCacheEntryParent,
                                         public MainProcessRunnable
 {
 public:
   // The given principal comes from an IPC::Principal which will be dec-refed
   // at the end of the message, so we must ref-count it here. Fortunately, we
   // are on the main thread (where PContent messages are delivered).
   ParentProcessRunnable(nsIPrincipal* aPrincipal,
                         OpenMode aOpenMode,
                         WriteParams aWriteParams)
   : MainProcessRunnable(aPrincipal, aOpenMode, aWriteParams),
     mPrincipalHolder(aPrincipal),
     mActorDestroyed(false),
     mOpened(false),
     mFinished(false)
   {
     MOZ_ASSERT(IsMainProcess());
     MOZ_ASSERT(NS_IsMainThread());
     MOZ_COUNT_CTOR(ParentProcessRunnable);
   }
 private:
   ~ParentProcessRunnable()
   {
     MOZ_ASSERT(!mPrincipalHolder, "Should have already been released");
     MOZ_ASSERT(mActorDestroyed);
     MOZ_ASSERT(mFinished);
     MOZ_COUNT_DTOR(ParentProcessRunnable);
   }
   bool
   Recv__delete__() MOZ_OVERRIDE
   {
     MOZ_ASSERT(!mFinished);
     mFinished = true;
     if (mOpened) {
       MainProcessRunnable::Close();
     } else {
       MainProcessRunnable::Fail();
     }
     return true;
   }
   void
   ActorDestroy(ActorDestroyReason why) MOZ_OVERRIDE
   {
     MOZ_ASSERT(!mActorDestroyed);
     mActorDestroyed = true;
     // Assume ActorDestroy can happen at any time, so probe the current state to
     // determine what needs to happen.
     if (mFinished) {
       return;
     }
     mFinished = true;
     if (mOpened) {
       MainProcessRunnable::Close();
     } else {
       MainProcessRunnable::Fail();
     }
   }
   void
   OnOpenMetadataForRead(const Metadata& aMetadata) MOZ_OVERRIDE
   {
     MOZ_ASSERT(NS_IsMainThread());
     if (!SendOnOpenMetadataForRead(aMetadata)) {
       unused << Send__delete__(this);
     }
   }
   bool
   RecvSelectCacheFileToRead(const uint32_t& aModuleIndex) MOZ_OVERRIDE
   {
     MainProcessRunnable::OpenForRead(aModuleIndex);
     return true;
   }
   bool
   RecvCacheMiss() MOZ_OVERRIDE
   {
     MainProcessRunnable::CacheMiss();
     return true;
   }
   void
   OnOpenCacheFile() MOZ_OVERRIDE
   {
     MOZ_ASSERT(NS_IsMainThread());
     MOZ_ASSERT(!mOpened);
     mOpened = true;
     FileDescriptor::PlatformHandleType handle =
       FileDescriptor::PlatformHandleType(PR_FileDesc2NativeHandle(mFileDesc));
     if (!SendOnOpenCacheFile(mFileSize, handle)) {
       unused << Send__delete__(this);
     }
   }
   void
   OnClose() MOZ_OVERRIDE MOZ_FINAL
   {
     MOZ_ASSERT(NS_IsMainThread());
     MOZ_ASSERT(mOpened);
     mFinished = true;
     MainProcessRunnable::OnClose();
     MOZ_ASSERT(mActorDestroyed);
     mPrincipalHolder = nullptr;
   }
   void
   OnFailure() MOZ_OVERRIDE
   {
     MOZ_ASSERT(NS_IsMainThread());
     MOZ_ASSERT(!mOpened);
     mFinished = true;
     MainProcessRunnable::OnFailure();
     if (!mActorDestroyed) {
       unused << Send__delete__(this);
     }
     mPrincipalHolder = nullptr;
   }
   nsCOMPtr<nsIPrincipal> mPrincipalHolder;
   bool mActorDestroyed;
   bool mOpened;
   bool mFinished;
 };
 } // unnamed namespace
 PAsmJSCacheEntryParent*
 AllocEntryParent(OpenMode aOpenMode,
                  WriteParams aWriteParams,
                  nsIPrincipal* aPrincipal)
 {
   ParentProcessRunnable* runnable =
     new ParentProcessRunnable(aPrincipal, aOpenMode, aWriteParams);
   // AddRef to keep the runnable alive until DeallocEntryParent.
   runnable->AddRef();
   nsresult rv = NS_DispatchToMainThread(runnable);
   NS_ENSURE_SUCCESS(rv, nullptr);
   return runnable;
 }
 void
 DeallocEntryParent(PAsmJSCacheEntryParent* aActor)
 {
   // Match the AddRef in AllocEntryParent.
   static_cast<ParentProcessRunnable*>(aActor)->Release();
 }
 namespace {
 class ChildProcessRunnable MOZ_FINAL : public File,
                                        public PAsmJSCacheEntryChild
 {
 public:
   NS_DECL_NSIRUNNABLE
   // In the single-process case, the calling JS compilation thread holds the
   // nsIPrincipal alive indirectly (via the global object -> compartment ->
   // principal) so we don't have to ref-count it here. This is fortunate since
   // we are off the main thread and nsIPrincipals can only be ref-counted on
   // the main thread.
   ChildProcessRunnable(nsIPrincipal* aPrincipal,
                        OpenMode aOpenMode,
                        WriteParams aWriteParams,
                        ReadParams aReadParams)
   : mPrincipal(aPrincipal),
     mOpenMode(aOpenMode),
     mWriteParams(aWriteParams),
     mReadParams(aReadParams),
     mActorDestroyed(false),
     mState(eInitial)
   {
     MOZ_ASSERT(!IsMainProcess());
     MOZ_ASSERT(!NS_IsMainThread());
     MOZ_COUNT_CTOR(ChildProcessRunnable);
   }
   ~ChildProcessRunnable()
   {
     MOZ_ASSERT(mState == eFinished);
     MOZ_ASSERT(mActorDestroyed);
     MOZ_COUNT_DTOR(ChildProcessRunnable);
   }
 private:
   bool
   RecvOnOpenMetadataForRead(const Metadata& aMetadata) MOZ_OVERRIDE
   {
     MOZ_ASSERT(NS_IsMainThread());
     MOZ_ASSERT(mState == eOpening);
     uint32_t moduleIndex;
     if (FindHashMatch(aMetadata, mReadParams, &moduleIndex)) {
       return SendSelectCacheFileToRead(moduleIndex);
     }
     return SendCacheMiss();
   }
   bool
   RecvOnOpenCacheFile(const int64_t& aFileSize,
                       const FileDescriptor& aFileDesc) MOZ_OVERRIDE
   {
     MOZ_ASSERT(NS_IsMainThread());
     MOZ_ASSERT(mState == eOpening);
     mFileSize = aFileSize;
     mFileDesc = PR_ImportFile(PROsfd(aFileDesc.PlatformHandle()));
     if (!mFileDesc) {
       return false;
     }
     mState = eOpened;
     File::OnOpen();
     return true;
   }
   bool
   Recv__delete__() MOZ_OVERRIDE
   {
     MOZ_ASSERT(NS_IsMainThread());
     MOZ_ASSERT(mState == eOpening);
     Fail();
     return true;
   }
   void
   ActorDestroy(ActorDestroyReason why) MOZ_OVERRIDE
   {
     MOZ_ASSERT(NS_IsMainThread());
     mActorDestroyed = true;
   }
   void
   Close() MOZ_OVERRIDE MOZ_FINAL
   {
     MOZ_ASSERT(mState == eOpened);
     mState = eClosing;
     NS_DispatchToMainThread(this);
   }
 private:
   void
   Fail()
   {
     MOZ_ASSERT(NS_IsMainThread());
     MOZ_ASSERT(mState == eInitial || mState == eOpening);
     mState = eFinished;
     File::OnFailure();
   }
   nsIPrincipal* const mPrincipal;
   const OpenMode mOpenMode;
   WriteParams mWriteParams;
   ReadParams mReadParams;
   bool mActorDestroyed;
   enum State {
     eInitial, // Just created, waiting to dispatched to the main thread
     eOpening, // Waiting for the parent process to respond
     eOpened, // Parent process opened the entry and sent it back
     eClosing, // Waiting to be dispatched to the main thread to Send__delete__
     eFinished // Terminal state
   };
   State mState;
 };
 NS_IMETHODIMP
 ChildProcessRunnable::Run()
 {
   switch (mState) {
     case eInitial: {
       MOZ_ASSERT(NS_IsMainThread());
       // AddRef to keep this runnable alive until IPDL deallocates the
       // subprotocol (DeallocEntryChild).
       AddRef();
       if (!ContentChild::GetSingleton()->SendPAsmJSCacheEntryConstructor(
         this, mOpenMode, mWriteParams, IPC::Principal(mPrincipal)))
       {
         // On failure, undo the AddRef (since DeallocEntryChild will not be
         // called) and unblock the parsing thread with a failure. The main
         // thread event loop still holds an outstanding ref which will keep
         // 'this' alive until returning to the event loop.
         Release();
         Fail();
         return NS_OK;
       }
       mState = eOpening;
       return NS_OK;
     }
     case eClosing: {
       MOZ_ASSERT(NS_IsMainThread());
       // Per FileDescriptorHolder::Finish()'s comment, call before
       // AllowNextSynchronizedOp (which happens in the parent upon receipt of
       // the Send__delete__ message).
       File::OnClose();
       if (!mActorDestroyed) {
         unused << Send__delete__(this);
       }
       mState = eFinished;
       return NS_OK;
     }
     case eOpening:
     case eOpened:
     case eFinished: {
       MOZ_ASSUME_UNREACHABLE("Shouldn't Run() in this state");
     }
   }
   MOZ_ASSUME_UNREACHABLE("Corrupt state");
   return NS_OK;
 }
 } // unnamed namespace
 void
 DeallocEntryChild(PAsmJSCacheEntryChild* aActor)
 {
   // Match the AddRef before SendPAsmJSCacheEntryConstructor.
   static_cast<ChildProcessRunnable*>(aActor)->Release();
 }
 namespace {
 bool
 OpenFile(nsIPrincipal* aPrincipal,
          OpenMode aOpenMode,
          WriteParams aWriteParams,
          ReadParams aReadParams,
          File::AutoClose* aFile)
 {
   MOZ_ASSERT_IF(aOpenMode == eOpenForRead, aWriteParams.mSize == 0);
   MOZ_ASSERT_IF(aOpenMode == eOpenForWrite, aReadParams.mBegin == nullptr);
   // There are three reasons we don't attempt caching from the main thread:
   //  1. In the parent process: QuotaManager::WaitForOpenAllowed prevents
   //     synchronous waiting on the main thread requiring a runnable to be
   //     dispatched to the main thread.
   //  2. In the child process: the IPDL PContent messages we need to
   //     synchronously wait on are dispatched to the main thread.
   //  3. While a cache lookup *should* be much faster than compilation, IO
   //     operations can be unpredictably slow and we'd like to avoid the
   //     occasional janks on the main thread.
   // We could use a nested event loop to address 1 and 2, but we're potentially
   // in the middle of running JS (eval()) and nested event loops can be
   // semantically observable.
   if (NS_IsMainThread()) {
     return false;
   }
   // If we are in a child process, we need to synchronously call into the
   // parent process to open the file and interact with the QuotaManager. The
   // child can then map the file into its address space to perform I/O.
   nsRefPtr<File> file;
   if (IsMainProcess()) {
     file = new SingleProcessRunnable(aPrincipal, aOpenMode, aWriteParams,
                                      aReadParams);
   } else {
     file = new ChildProcessRunnable(aPrincipal, aOpenMode, aWriteParams,
                                     aReadParams);
   }
   if (!file->BlockUntilOpen(aFile)) {
     return false;
   }
   return file->MapMemory(aOpenMode);
 }
 } // anonymous namespace
 typedef uint32_t AsmJSCookieType;
 static const uint32_t sAsmJSCookie = 0x600d600d;
 bool
 OpenEntryForRead(nsIPrincipal* aPrincipal,
                  const jschar* aBegin,
                  const jschar* aLimit,
                  size_t* aSize,
                  const uint8_t** aMemory,
                  intptr_t* aFile)
 {
   if (size_t(aLimit - aBegin) < sMinCachedModuleLength) {
     return false;
   }
   ReadParams readParams;
   readParams.mBegin = aBegin;
   readParams.mLimit = aLimit;
   File::AutoClose file;
   WriteParams notAWrite;
   if (!OpenFile(aPrincipal, eOpenForRead, notAWrite, readParams, &file)) {
     return false;
   }
   // Although we trust that the stored cache files have not been arbitrarily
   // corrupted, it is possible that a previous execution aborted in the middle
   // of writing a cache file (crash, OOM-killer, etc). To protect against
   // partially-written cache files, we use the following scheme:
   //  - Allocate an extra word at the beginning of every cache file which
   //    starts out 0 (OpenFile opens with PR_TRUNCATE).
   //  - After the asm.js serialization is complete, PR_SyncMemMap to write
   //    everything to disk and then store a non-zero value (sAsmJSCookie)
   //    in the first word.
   //  - When attempting to read a cache file, check whether the first word is
   //    sAsmJSCookie.
   if (file->FileSize() < sizeof(AsmJSCookieType) ||
       *(AsmJSCookieType*)file->MappedMemory() != sAsmJSCookie) {
     return false;
   }
   *aSize = file->FileSize() - sizeof(AsmJSCookieType);
   *aMemory = (uint8_t*) file->MappedMemory() + sizeof(AsmJSCookieType);
   // The caller guarnatees a call to CloseEntryForRead (on success or
   // failure) at which point the file will be closed.
   file.Forget(reinterpret_cast<File**>(aFile));
   return true;
 }
 void
 CloseEntryForRead(JS::Handle<JSObject*> global,
                   size_t aSize,
                   const uint8_t* aMemory,
                   intptr_t aFile)
 {
   File::AutoClose file(reinterpret_cast<File*>(aFile));
   MOZ_ASSERT(aSize + sizeof(AsmJSCookieType) == file->FileSize());
   MOZ_ASSERT(aMemory - sizeof(AsmJSCookieType) == file->MappedMemory());
 }
 bool
 OpenEntryForWrite(nsIPrincipal* aPrincipal,
                   bool aInstalled,
                   const jschar* aBegin,
                   const jschar* aEnd,
                   size_t aSize,
                   uint8_t** aMemory,
                   intptr_t* aFile)
 {
   if (size_t(aEnd - aBegin) < sMinCachedModuleLength) {
     return false;
   }
   // Add extra space for the AsmJSCookieType (see OpenEntryForRead).
   aSize += sizeof(AsmJSCookieType);
   static_assert(sNumFastHashChars < sMinCachedModuleLength, "HashString safe");
   WriteParams writeParams;
   writeParams.mInstalled = aInstalled;
   writeParams.mSize = aSize;
   writeParams.mFastHash = HashString(aBegin, sNumFastHashChars);
   writeParams.mNumChars = aEnd - aBegin;
   writeParams.mFullHash = HashString(aBegin, writeParams.mNumChars);
   File::AutoClose file;
   ReadParams notARead;
   if (!OpenFile(aPrincipal, eOpenForWrite, writeParams, notARead, &file)) {
     return false;
   }
   // Strip off the AsmJSCookieType from the buffer returned to the caller,
   // which expects a buffer of aSize, not a buffer of sizeWithCookie starting
   // with a cookie.
   *aMemory = (uint8_t*) file->MappedMemory() + sizeof(AsmJSCookieType);
   // The caller guarnatees a call to CloseEntryForWrite (on success or
   // failure) at which point the file will be closed
   file.Forget(reinterpret_cast<File**>(aFile));
   return true;
 }
 void
 CloseEntryForWrite(JS::Handle<JSObject*> global,
                    size_t aSize,
                    uint8_t* aMemory,
                    intptr_t aFile)
 {
   File::AutoClose file(reinterpret_cast<File*>(aFile));
   MOZ_ASSERT(aSize + sizeof(AsmJSCookieType) == file->FileSize());
   MOZ_ASSERT(aMemory - sizeof(AsmJSCookieType) == file->MappedMemory());
   // Flush to disk before writing the cookie (see OpenEntryForRead).
   if (PR_SyncMemMap(file->FileDesc(),
                     file->MappedMemory(),
                     file->FileSize()) == PR_SUCCESS) {
     *(AsmJSCookieType*)file->MappedMemory() = sAsmJSCookie;
   }
 }
 bool
 GetBuildId(JS::BuildIdCharVector* aBuildID)
 {
   nsCOMPtr<nsIXULAppInfo> info = do_GetService("@mozilla.org/xre/app-info;1");
   if (!info) {
     return false;
   }
   nsCString buildID;
   nsresult rv = info->GetPlatformBuildID(buildID);
   NS_ENSURE_SUCCESS(rv, false);
   if (!aBuildID->resize(buildID.Length())) {
     return false;
   }
   for (size_t i = 0; i < buildID.Length(); i++) {
     (*aBuildID)[i] = buildID[i];
   }
   return true;
 }
 class Client : public quota::Client
 {
 public:
   NS_IMETHOD_(MozExternalRefCountType)
   AddRef() MOZ_OVERRIDE;
   NS_IMETHOD_(MozExternalRefCountType)
   Release() MOZ_OVERRIDE;
   virtual Type
   GetType() MOZ_OVERRIDE
   {
     return ASMJS;
   }
   virtual nsresult
   InitOrigin(PersistenceType aPersistenceType,
              const nsACString& aGroup,
              const nsACString& aOrigin,
              UsageInfo* aUsageInfo) MOZ_OVERRIDE
   {
     if (!aUsageInfo) {
       return NS_OK;
     }
     return GetUsageForOrigin(aPersistenceType, aGroup, aOrigin, aUsageInfo);
   }
   virtual nsresult
   GetUsageForOrigin(PersistenceType aPersistenceType,
                     const nsACString& aGroup,
                     const nsACString& aOrigin,
                     UsageInfo* aUsageInfo) MOZ_OVERRIDE
   {
     QuotaManager* qm = QuotaManager::Get();
     MOZ_ASSERT(qm, "We were being called by the QuotaManager");
     nsCOMPtr<nsIFile> directory;
     nsresult rv = qm->GetDirectoryForOrigin(aPersistenceType, aOrigin,
                                             getter_AddRefs(directory));
     NS_ENSURE_SUCCESS(rv, rv);
     MOZ_ASSERT(directory, "We're here because the origin directory exists");
     rv = directory->Append(NS_LITERAL_STRING(ASMJSCACHE_DIRECTORY_NAME));
     NS_ENSURE_SUCCESS(rv, rv);
     DebugOnly<bool> exists;
     MOZ_ASSERT(NS_SUCCEEDED(directory->Exists(&exists)) && exists);
     nsCOMPtr<nsISimpleEnumerator> entries;
     rv = directory->GetDirectoryEntries(getter_AddRefs(entries));
     NS_ENSURE_SUCCESS(rv, rv);
     bool hasMore;
     while (NS_SUCCEEDED((rv = entries->HasMoreElements(&hasMore))) &&
            hasMore && !aUsageInfo->Canceled()) {
       nsCOMPtr<nsISupports> entry;
       rv = entries->GetNext(getter_AddRefs(entry));
       NS_ENSURE_SUCCESS(rv, rv);
       nsCOMPtr<nsIFile> file = do_QueryInterface(entry);
       NS_ENSURE_TRUE(file, NS_NOINTERFACE);
       int64_t fileSize;
       rv = file->GetFileSize(&fileSize);
       NS_ENSURE_SUCCESS(rv, rv);
       MOZ_ASSERT(fileSize >= 0, "Negative size?!");
       // Since the client is not explicitly storing files, append to database
       // usage which represents implicit storage allocation.
       aUsageInfo->AppendToDatabaseUsage(uint64_t(fileSize));
     }
     NS_ENSURE_SUCCESS(rv, rv);
     return NS_OK;
   }
   virtual void
   OnOriginClearCompleted(PersistenceType aPersistenceType,
                          const OriginOrPatternString& aOriginOrPattern)
                          MOZ_OVERRIDE
   { }
   virtual void
   ReleaseIOThreadObjects() MOZ_OVERRIDE
   { }
   virtual bool
   IsFileServiceUtilized() MOZ_OVERRIDE
   {
     return false;
   }
   virtual bool
   IsTransactionServiceActivated() MOZ_OVERRIDE
   {
     return false;
   }
   virtual void
   WaitForStoragesToComplete(nsTArray<nsIOfflineStorage*>& aStorages,
                             nsIRunnable* aCallback) MOZ_OVERRIDE
   {
     MOZ_ASSUME_UNREACHABLE("There are no storages");
   }
   virtual void
   AbortTransactionsForStorage(nsIOfflineStorage* aStorage) MOZ_OVERRIDE
   {
     MOZ_ASSUME_UNREACHABLE("There are no storages");
   }
   virtual bool
   HasTransactionsForStorage(nsIOfflineStorage* aStorage) MOZ_OVERRIDE
   {
     return false;
   }
   virtual void
   ShutdownTransactionService() MOZ_OVERRIDE
   { }
 private:
   nsAutoRefCnt mRefCnt;
   NS_DECL_OWNINGTHREAD
 };
 NS_IMPL_ADDREF(asmjscache::Client)
 NS_IMPL_RELEASE(asmjscache::Client)
 quota::Client*
 CreateClient()
 {
   return new Client();
 }
 } // namespace asmjscache
 } // namespace dom
 } // namespace mozilla
 namespace IPC {
 using mozilla::dom::asmjscache::Metadata;
 using mozilla::dom::asmjscache::WriteParams;
 void
 ParamTraits<Metadata>::Write(Message* aMsg, const paramType& aParam)
 {
   for (unsigned i = 0; i < Metadata::kNumEntries; i++) {
     const Metadata::Entry& entry = aParam.mEntries[i];
     WriteParam(aMsg, entry.mFastHash);
     WriteParam(aMsg, entry.mNumChars);
     WriteParam(aMsg, entry.mFullHash);
     WriteParam(aMsg, entry.mModuleIndex);
   }
 }
 bool
 ParamTraits<Metadata>::Read(const Message* aMsg, void** aIter,
                             paramType* aResult)
 {
   for (unsigned i = 0; i < Metadata::kNumEntries; i++) {
     Metadata::Entry& entry = aResult->mEntries[i];
     if (!ReadParam(aMsg, aIter, &entry.mFastHash) ||
         !ReadParam(aMsg, aIter, &entry.mNumChars) ||
         !ReadParam(aMsg, aIter, &entry.mFullHash) ||
         !ReadParam(aMsg, aIter, &entry.mModuleIndex))
     {
       return false;
     }
   }
   return true;
 }
 void
 ParamTraits<Metadata>::Log(const paramType& aParam, std::wstring* aLog)
 {
   for (unsigned i = 0; i < Metadata::kNumEntries; i++) {
     const Metadata::Entry& entry = aParam.mEntries[i];
     LogParam(entry.mFastHash, aLog);
     LogParam(entry.mNumChars, aLog);
     LogParam(entry.mFullHash, aLog);
     LogParam(entry.mModuleIndex, aLog);
   }
 }
 void
 ParamTraits<WriteParams>::Write(Message* aMsg, const paramType& aParam)
 {
   WriteParam(aMsg, aParam.mSize);
   WriteParam(aMsg, aParam.mFastHash);
   WriteParam(aMsg, aParam.mNumChars);
   WriteParam(aMsg, aParam.mFullHash);
   WriteParam(aMsg, aParam.mInstalled);
 }
 bool
 ParamTraits<WriteParams>::Read(const Message* aMsg, void** aIter,
                                paramType* aResult)
 {
   return ReadParam(aMsg, aIter, &aResult->mSize) &&
          ReadParam(aMsg, aIter, &aResult->mFastHash) &&
          ReadParam(aMsg, aIter, &aResult->mNumChars) &&
          ReadParam(aMsg, aIter, &aResult->mFullHash) &&
          ReadParam(aMsg, aIter, &aResult->mInstalled);
 }
 void
 ParamTraits<WriteParams>::Log(const paramType& aParam, std::wstring* aLog)
 {
   LogParam(aParam.mSize, aLog);
   LogParam(aParam.mFastHash, aLog);
   LogParam(aParam.mNumChars, aLog);
   LogParam(aParam.mFullHash, aLog);
   LogParam(aParam.mInstalled, aLog);
 }
 } // namespace IPC

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dom/asmjscache/AsmJSCache.cpp@b8a032363ba2 (annotated)

dom/asmjscache/AsmJSCache.cpp