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Diffstat (limited to 'dom/cache/FileUtils.cpp')
| -rw-r--r-- | dom/cache/FileUtils.cpp | 778 |
1 files changed, 778 insertions, 0 deletions
diff --git a/dom/cache/FileUtils.cpp b/dom/cache/FileUtils.cpp new file mode 100644 index 0000000000..9c6b1f60e6 --- /dev/null +++ b/dom/cache/FileUtils.cpp @@ -0,0 +1,778 @@ +/* -*- 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/. */ + +#include "FileUtilsImpl.h" + +#include "DBSchema.h" +#include "mozilla/dom/InternalResponse.h" +#include "mozilla/dom/quota/FileStreams.h" +#include "mozilla/dom/quota/QuotaManager.h" +#include "mozilla/dom/quota/QuotaObject.h" +#include "mozilla/dom/quota/ResultExtensions.h" +#include "mozilla/ScopeExit.h" +#include "mozilla/SnappyCompressOutputStream.h" +#include "mozilla/Unused.h" +#include "nsIObjectInputStream.h" +#include "nsIObjectOutputStream.h" +#include "nsIFile.h" +#include "nsIUUIDGenerator.h" +#include "nsNetCID.h" +#include "nsNetUtil.h" +#include "nsServiceManagerUtils.h" +#include "nsString.h" +#include "nsThreadUtils.h" +#include "snappy/snappy.h" + +namespace mozilla::dom::cache { + +static_assert(SNAPPY_VERSION == 0x010109); + +using mozilla::dom::quota::Client; +using mozilla::dom::quota::CloneFileAndAppend; +using mozilla::dom::quota::FileInputStream; +using mozilla::dom::quota::FileOutputStream; +using mozilla::dom::quota::GetDirEntryKind; +using mozilla::dom::quota::nsIFileKind; +using mozilla::dom::quota::PERSISTENCE_TYPE_DEFAULT; +using mozilla::dom::quota::QuotaManager; +using mozilla::dom::quota::QuotaObject; + +namespace { + +// Const variable for generate padding size. +// XXX This will be tweaked to something more meaningful in Bug 1383656. +const int64_t kRoundUpNumber = 20480; + +enum BodyFileType { BODY_FILE_FINAL, BODY_FILE_TMP }; + +Result<NotNull<nsCOMPtr<nsIFile>>, nsresult> BodyIdToFile(nsIFile& aBaseDir, + const nsID& aId, + BodyFileType aType); + +int64_t RoundUp(int64_t aX, int64_t aY); + +// The alogrithm for generating padding refers to the mitigation approach in +// https://github.com/whatwg/storage/issues/31. +// First, generate a random number between 0 and 100kB. +// Next, round up the sum of random number and response size to the nearest +// 20kB. +// Finally, the virtual padding size will be the result minus the response size. +int64_t BodyGeneratePadding(int64_t aBodyFileSize, uint32_t aPaddingInfo); + +nsresult DirectoryPaddingWrite(nsIFile& aBaseDir, + DirPaddingFile aPaddingFileType, + int64_t aPaddingSize); + +const auto kMorgueDirectory = u"morgue"_ns; + +bool IsFileNotFoundError(const nsresult aRv) { + return aRv == NS_ERROR_FILE_NOT_FOUND; +} + +Result<NotNull<nsCOMPtr<nsIFile>>, nsresult> BodyGetCacheDir(nsIFile& aBaseDir, + const nsID& aId) { + QM_TRY_UNWRAP(auto cacheDir, CloneFileAndAppend(aBaseDir, kMorgueDirectory)); + + // Some file systems have poor performance when there are too many files + // in a single directory. Mitigate this issue by spreading the body + // files out into sub-directories. We use the last byte of the ID for + // the name of the sub-directory. + QM_TRY(MOZ_TO_RESULT(cacheDir->Append(IntToString(aId.m3[7])))); + + // Callers call this function without checking if the directory already + // exists (idempotent usage). QM_OR_ELSE_WARN_IF is not used here since we + // just want to log NS_ERROR_FILE_ALREADY_EXISTS result and not spam the + // reports. + QM_TRY(QM_OR_ELSE_LOG_VERBOSE_IF( + // Expression. + MOZ_TO_RESULT(cacheDir->Create(nsIFile::DIRECTORY_TYPE, 0755)), + // Predicate. + IsSpecificError<NS_ERROR_FILE_ALREADY_EXISTS>, + // Fallback. + ErrToDefaultOk<>)); + + return WrapNotNullUnchecked(std::move(cacheDir)); +} + +} // namespace + +nsresult BodyCreateDir(nsIFile& aBaseDir) { + QM_TRY_INSPECT(const auto& bodyDir, + CloneFileAndAppend(aBaseDir, kMorgueDirectory)); + + // Callers call this function without checking if the directory already + // exists (idempotent usage). QM_OR_ELSE_WARN_IF is not used here since we + // just want to log NS_ERROR_FILE_ALREADY_EXISTS result and not spam the + // reports. + QM_TRY(QM_OR_ELSE_LOG_VERBOSE_IF( + // Expression. + MOZ_TO_RESULT(bodyDir->Create(nsIFile::DIRECTORY_TYPE, 0755)), + // Predicate. + IsSpecificError<NS_ERROR_FILE_ALREADY_EXISTS>, + // Fallback. + ErrToDefaultOk<>)); + + return NS_OK; +} + +nsresult BodyDeleteDir(const CacheDirectoryMetadata& aDirectoryMetadata, + nsIFile& aBaseDir) { + QM_TRY_INSPECT(const auto& bodyDir, + CloneFileAndAppend(aBaseDir, kMorgueDirectory)); + + QM_TRY(MOZ_TO_RESULT(RemoveNsIFileRecursively(aDirectoryMetadata, *bodyDir))); + + return NS_OK; +} + +Result<std::pair<nsID, nsCOMPtr<nsISupports>>, nsresult> BodyStartWriteStream( + const CacheDirectoryMetadata& aDirectoryMetadata, nsIFile& aBaseDir, + nsIInputStream& aSource, void* aClosure, nsAsyncCopyCallbackFun aCallback) { + MOZ_DIAGNOSTIC_ASSERT(aClosure); + MOZ_DIAGNOSTIC_ASSERT(aCallback); + + QM_TRY_INSPECT(const auto& idGen, + MOZ_TO_RESULT_GET_TYPED(nsCOMPtr<nsIUUIDGenerator>, + MOZ_SELECT_OVERLOAD(do_GetService), + "@mozilla.org/uuid-generator;1")); + + nsID id; + QM_TRY(MOZ_TO_RESULT(idGen->GenerateUUIDInPlace(&id))); + + QM_TRY_INSPECT(const auto& finalFile, + BodyIdToFile(aBaseDir, id, BODY_FILE_FINAL)); + + { + QM_TRY_INSPECT(const bool& exists, + MOZ_TO_RESULT_INVOKE_MEMBER(*finalFile, Exists)); + + QM_TRY(OkIf(!exists), Err(NS_ERROR_FILE_ALREADY_EXISTS)); + } + + QM_TRY_INSPECT(const auto& tmpFile, + BodyIdToFile(aBaseDir, id, BODY_FILE_TMP)); + + QM_TRY_UNWRAP( + nsCOMPtr<nsIOutputStream> fileStream, + CreateFileOutputStream(PERSISTENCE_TYPE_DEFAULT, aDirectoryMetadata, + Client::DOMCACHE, tmpFile.get())); + + const auto compressed = MakeRefPtr<SnappyCompressOutputStream>(fileStream); + + const nsCOMPtr<nsIEventTarget> target = + do_GetService(NS_STREAMTRANSPORTSERVICE_CONTRACTID); + + nsCOMPtr<nsISupports> copyContext; + QM_TRY(MOZ_TO_RESULT( + NS_AsyncCopy(&aSource, compressed, target, NS_ASYNCCOPY_VIA_WRITESEGMENTS, + compressed->BlockSize(), aCallback, aClosure, true, + true, // close streams + getter_AddRefs(copyContext)))); + + return std::make_pair(id, std::move(copyContext)); +} + +void BodyCancelWrite(nsISupports& aCopyContext) { + QM_WARNONLY_TRY( + QM_TO_RESULT(NS_CancelAsyncCopy(&aCopyContext, NS_ERROR_ABORT))); + + // TODO The partially written file must be cleaned up after the async copy + // makes its callback. +} + +nsresult BodyFinalizeWrite(nsIFile& aBaseDir, const nsID& aId) { + QM_TRY_INSPECT(const auto& tmpFile, + BodyIdToFile(aBaseDir, aId, BODY_FILE_TMP)); + + QM_TRY_INSPECT(const auto& finalFile, + BodyIdToFile(aBaseDir, aId, BODY_FILE_FINAL)); + + nsAutoString finalFileName; + QM_TRY(MOZ_TO_RESULT(finalFile->GetLeafName(finalFileName))); + + // It's fine to not notify the QuotaManager that the path has been changed, + // because its path will be updated and its size will be recalculated when + // opening file next time. + QM_TRY(MOZ_TO_RESULT(tmpFile->RenameTo(nullptr, finalFileName))); + + return NS_OK; +} + +Result<MovingNotNull<nsCOMPtr<nsIInputStream>>, nsresult> BodyOpen( + const CacheDirectoryMetadata& aDirectoryMetadata, nsIFile& aBaseDir, + const nsID& aId) { + QM_TRY_INSPECT(const auto& finalFile, + BodyIdToFile(aBaseDir, aId, BODY_FILE_FINAL)); + + QM_TRY_RETURN(CreateFileInputStream(PERSISTENCE_TYPE_DEFAULT, + aDirectoryMetadata, Client::DOMCACHE, + finalFile.get())); +} + +nsresult BodyMaybeUpdatePaddingSize( + const CacheDirectoryMetadata& aDirectoryMetadata, nsIFile& aBaseDir, + const nsID& aId, const uint32_t aPaddingInfo, int64_t* aPaddingSizeInOut) { + MOZ_DIAGNOSTIC_ASSERT(aPaddingSizeInOut); + + QM_TRY_INSPECT(const auto& bodyFile, + BodyIdToFile(aBaseDir, aId, BODY_FILE_TMP)); + + QuotaManager* quotaManager = QuotaManager::Get(); + MOZ_DIAGNOSTIC_ASSERT(quotaManager); + + int64_t fileSize = 0; + RefPtr<QuotaObject> quotaObject = quotaManager->GetQuotaObject( + PERSISTENCE_TYPE_DEFAULT, aDirectoryMetadata, Client::DOMCACHE, + bodyFile.get(), -1, &fileSize); + MOZ_DIAGNOSTIC_ASSERT(quotaObject); + MOZ_DIAGNOSTIC_ASSERT(fileSize >= 0); + // XXXtt: bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1422815 + if (!quotaObject) { + return NS_ERROR_UNEXPECTED; + } + + if (*aPaddingSizeInOut == InternalResponse::UNKNOWN_PADDING_SIZE) { + *aPaddingSizeInOut = BodyGeneratePadding(fileSize, aPaddingInfo); + } + + MOZ_DIAGNOSTIC_ASSERT(*aPaddingSizeInOut >= 0); + + if (!quotaObject->IncreaseSize(*aPaddingSizeInOut)) { + return NS_ERROR_FILE_NO_DEVICE_SPACE; + } + + return NS_OK; +} + +nsresult BodyDeleteFiles(const CacheDirectoryMetadata& aDirectoryMetadata, + nsIFile& aBaseDir, const nsTArray<nsID>& aIdList) { + for (const auto id : aIdList) { + QM_TRY_INSPECT(const auto& bodyDir, BodyGetCacheDir(aBaseDir, id)); + + const auto removeFileForId = + [&aDirectoryMetadata, &id]( + nsIFile& bodyFile, + const nsACString& leafName) -> Result<bool, nsresult> { + nsID fileId; + QM_TRY(OkIf(fileId.Parse(leafName.BeginReading())), true, + ([&aDirectoryMetadata, &bodyFile](const auto) { + DebugOnly<nsresult> result = RemoveNsIFile( + aDirectoryMetadata, bodyFile, /* aTrackQuota */ false); + MOZ_ASSERT(NS_SUCCEEDED(result)); + })); + + if (id.Equals(fileId)) { + DebugOnly<nsresult> result = + RemoveNsIFile(aDirectoryMetadata, bodyFile); + MOZ_ASSERT(NS_SUCCEEDED(result)); + return true; + } + + return false; + }; + QM_TRY(MOZ_TO_RESULT(BodyTraverseFiles(aDirectoryMetadata, *bodyDir, + removeFileForId, + /* aCanRemoveFiles */ false, + /* aTrackQuota */ true))); + } + + return NS_OK; +} + +namespace { + +Result<NotNull<nsCOMPtr<nsIFile>>, nsresult> BodyIdToFile( + nsIFile& aBaseDir, const nsID& aId, const BodyFileType aType) { + QM_TRY_UNWRAP(auto bodyFile, BodyGetCacheDir(aBaseDir, aId)); + + char idString[NSID_LENGTH]; + aId.ToProvidedString(idString); + + NS_ConvertASCIItoUTF16 fileName(idString); + + if (aType == BODY_FILE_FINAL) { + fileName.AppendLiteral(".final"); + } else { + fileName.AppendLiteral(".tmp"); + } + + QM_TRY(MOZ_TO_RESULT(bodyFile->Append(fileName))); + + return bodyFile; +} + +int64_t RoundUp(const int64_t aX, const int64_t aY) { + MOZ_DIAGNOSTIC_ASSERT(aX >= 0); + MOZ_DIAGNOSTIC_ASSERT(aY > 0); + + MOZ_DIAGNOSTIC_ASSERT(INT64_MAX - ((aX - 1) / aY) * aY >= aY); + return aY + ((aX - 1) / aY) * aY; +} + +int64_t BodyGeneratePadding(const int64_t aBodyFileSize, + const uint32_t aPaddingInfo) { + // Generate padding + int64_t randomSize = static_cast<int64_t>(aPaddingInfo); + MOZ_DIAGNOSTIC_ASSERT(INT64_MAX - aBodyFileSize >= randomSize); + randomSize += aBodyFileSize; + + return RoundUp(randomSize, kRoundUpNumber) - aBodyFileSize; +} + +nsresult DirectoryPaddingWrite(nsIFile& aBaseDir, + DirPaddingFile aPaddingFileType, + int64_t aPaddingSize) { + MOZ_DIAGNOSTIC_ASSERT(aPaddingSize >= 0); + + QM_TRY_INSPECT( + const auto& file, + CloneFileAndAppend(aBaseDir, aPaddingFileType == DirPaddingFile::TMP_FILE + ? nsLiteralString(PADDING_TMP_FILE_NAME) + : nsLiteralString(PADDING_FILE_NAME))); + + QM_TRY_INSPECT(const auto& outputStream, NS_NewLocalFileOutputStream(file)); + + nsCOMPtr<nsIObjectOutputStream> objectStream = + NS_NewObjectOutputStream(outputStream); + + QM_TRY(MOZ_TO_RESULT(objectStream->Write64(aPaddingSize))); + + return NS_OK; +} + +} // namespace + +nsresult BodyDeleteOrphanedFiles( + const CacheDirectoryMetadata& aDirectoryMetadata, nsIFile& aBaseDir, + const nsTArray<nsID>& aKnownBodyIdList) { + // body files are stored in a directory structure like: + // + // /morgue/01/{01fdddb2-884d-4c3d-95ba-0c8062f6c325}.final + // /morgue/02/{02fdddb2-884d-4c3d-95ba-0c8062f6c325}.tmp + + QM_TRY_INSPECT(const auto& dir, + CloneFileAndAppend(aBaseDir, kMorgueDirectory)); + + // Iterate over all the intermediate morgue subdirs + QM_TRY(quota::CollectEachFile( + *dir, + [&aDirectoryMetadata, &aKnownBodyIdList]( + const nsCOMPtr<nsIFile>& subdir) -> Result<Ok, nsresult> { + QM_TRY_INSPECT(const auto& dirEntryKind, GetDirEntryKind(*subdir)); + + switch (dirEntryKind) { + case nsIFileKind::ExistsAsDirectory: { + const auto removeOrphanedFiles = + [&aDirectoryMetadata, &aKnownBodyIdList]( + nsIFile& bodyFile, + const nsACString& leafName) -> Result<bool, nsresult> { + // Finally, parse the uuid out of the name. If it fails to parse, + // then ignore the file. + auto cleanup = MakeScopeExit([&aDirectoryMetadata, &bodyFile] { + DebugOnly<nsresult> result = + RemoveNsIFile(aDirectoryMetadata, bodyFile); + MOZ_ASSERT(NS_SUCCEEDED(result)); + }); + + nsID id; + QM_TRY(OkIf(id.Parse(leafName.BeginReading())), true); + + if (!aKnownBodyIdList.Contains(id)) { + return true; + } + + cleanup.release(); + + return false; + }; + + // QM_OR_ELSE_WARN_IF is not used here since we just want to log + // NS_ERROR_FILE_FS_CORRUPTED result and not spam the reports (even + // a warning in the reports is not desired). + QM_TRY(QM_OR_ELSE_LOG_VERBOSE_IF( + // Expression. + MOZ_TO_RESULT(BodyTraverseFiles(aDirectoryMetadata, *subdir, + removeOrphanedFiles, + /* aCanRemoveFiles */ true, + /* aTrackQuota */ true)), + // Predicate. + IsSpecificError<NS_ERROR_FILE_FS_CORRUPTED>, + // Fallback. We treat NS_ERROR_FILE_FS_CORRUPTED as if the + // directory did not exist at all. + ErrToDefaultOk<>)); + break; + } + + case nsIFileKind::ExistsAsFile: { + // If a file got in here somehow, try to remove it and move on + DebugOnly<nsresult> result = + RemoveNsIFile(aDirectoryMetadata, *subdir, + /* aTrackQuota */ false); + MOZ_ASSERT(NS_SUCCEEDED(result)); + break; + } + + case nsIFileKind::DoesNotExist: + // Ignore files that got removed externally while iterating. + break; + } + + return Ok{}; + })); + + return NS_OK; +} + +namespace { + +Result<nsCOMPtr<nsIFile>, nsresult> GetMarkerFileHandle( + const CacheDirectoryMetadata& aDirectoryMetadata) { + QM_TRY_UNWRAP(auto marker, + CloneFileAndAppend(*aDirectoryMetadata.mDir, u"cache"_ns)); + + QM_TRY(MOZ_TO_RESULT(marker->Append(u"context_open.marker"_ns))); + + return marker; +} + +} // namespace + +nsresult CreateMarkerFile(const CacheDirectoryMetadata& aDirectoryMetadata) { + QM_TRY_INSPECT(const auto& marker, GetMarkerFileHandle(aDirectoryMetadata)); + + // Callers call this function without checking if the file already exists + // (idempotent usage). QM_OR_ELSE_WARN_IF is not used here since we just want + // to log NS_ERROR_FILE_ALREADY_EXISTS result and not spam the reports. + // + // TODO: In theory if this file exists, then Context::~Context should have + // cleaned it up, but obviously we can crash and not clean it up, which is + // the whole point of the marker file. In that case, we'll realize the marker + // file exists in SetupAction::RunSyncWithDBOnTarget and do some cleanup, but + // we won't delete the marker file, so if we see this marker file, it is part + // of our standard operating procedure to redundantly try and create the + // marker here. We currently treat this as idempotent usage, but we could + // make sure to delete the marker file when handling the existing marker + // file in SetupAction::RunSyncWithDBOnTarget and change + // QM_OR_ELSE_LOG_VERBOSE_IF to QM_OR_ELSE_WARN_IF in the end. + QM_TRY(QM_OR_ELSE_LOG_VERBOSE_IF( + // Expression. + MOZ_TO_RESULT(marker->Create(nsIFile::NORMAL_FILE_TYPE, 0644)), + // Predicate. + IsSpecificError<NS_ERROR_FILE_ALREADY_EXISTS>, + // Fallback. + ErrToDefaultOk<>)); + + // Note, we don't need to fsync here. We only care about actually + // writing the marker if later modifications to the Cache are + // actually flushed to the disk. If the OS crashes before the marker + // is written then we are ensured no other changes to the Cache were + // flushed either. + + return NS_OK; +} + +nsresult DeleteMarkerFile(const CacheDirectoryMetadata& aDirectoryMetadata) { + QM_TRY_INSPECT(const auto& marker, GetMarkerFileHandle(aDirectoryMetadata)); + + DebugOnly<nsresult> result = + RemoveNsIFile(aDirectoryMetadata, *marker, /* aTrackQuota */ false); + MOZ_ASSERT(NS_SUCCEEDED(result)); + + // Again, no fsync is necessary. If the OS crashes before the file + // removal is flushed, then the Cache will search for stale data on + // startup. This will cause the next Cache access to be a bit slow, but + // it seems appropriate after an OS crash. + + return NS_OK; +} + +bool MarkerFileExists(const CacheDirectoryMetadata& aDirectoryMetadata) { + QM_TRY_INSPECT(const auto& marker, GetMarkerFileHandle(aDirectoryMetadata), + false); + + QM_TRY_RETURN(MOZ_TO_RESULT_INVOKE_MEMBER(marker, Exists), false); +} + +nsresult RemoveNsIFileRecursively( + const Maybe<CacheDirectoryMetadata>& aDirectoryMetadata, nsIFile& aFile, + const bool aTrackQuota) { + // XXX This assertion proves that we can remove aTrackQuota and just check + // aClientMetadata + MOZ_DIAGNOSTIC_ASSERT_IF(aTrackQuota, aDirectoryMetadata); + + QM_TRY_INSPECT(const auto& dirEntryKind, GetDirEntryKind(aFile)); + + switch (dirEntryKind) { + case nsIFileKind::ExistsAsDirectory: + // Unfortunately, we need to traverse all the entries and delete files one + // by + // one to update their usages to the QuotaManager. + QM_TRY(quota::CollectEachFile( + aFile, + [&aDirectoryMetadata, &aTrackQuota]( + const nsCOMPtr<nsIFile>& file) -> Result<Ok, nsresult> { + QM_TRY(MOZ_TO_RESULT(RemoveNsIFileRecursively(aDirectoryMetadata, + *file, aTrackQuota))); + + return Ok{}; + })); + + // In the end, remove the folder + QM_TRY(MOZ_TO_RESULT(aFile.Remove(/* recursive */ false))); + + break; + + case nsIFileKind::ExistsAsFile: + return RemoveNsIFile(aDirectoryMetadata, aFile, aTrackQuota); + + case nsIFileKind::DoesNotExist: + // Ignore files that got removed externally while iterating. + break; + } + + return NS_OK; +} + +nsresult RemoveNsIFile(const Maybe<CacheDirectoryMetadata>& aDirectoryMetadata, + nsIFile& aFile, const bool aTrackQuota) { + // XXX This assertion proves that we can remove aTrackQuota and just check + // aClientMetadata + MOZ_DIAGNOSTIC_ASSERT_IF(aTrackQuota, aDirectoryMetadata); + + int64_t fileSize = 0; + if (aTrackQuota) { + QM_TRY_INSPECT( + const auto& maybeFileSize, + QM_OR_ELSE_WARN_IF( + // Expression. + MOZ_TO_RESULT_INVOKE_MEMBER(aFile, GetFileSize).map(Some<int64_t>), + // Predicate. + IsFileNotFoundError, + // Fallback. + ErrToDefaultOk<Maybe<int64_t>>)); + + if (!maybeFileSize) { + return NS_OK; + } + + fileSize = *maybeFileSize; + } + + QM_TRY(QM_OR_ELSE_WARN_IF( + // Expression. + MOZ_TO_RESULT(aFile.Remove(/* recursive */ false)), + // Predicate. + IsFileNotFoundError, + // Fallback. + ErrToDefaultOk<>)); + + if (fileSize > 0) { + MOZ_ASSERT(aTrackQuota); + DecreaseUsageForDirectoryMetadata(*aDirectoryMetadata, fileSize); + } + + return NS_OK; +} + +void DecreaseUsageForDirectoryMetadata( + const CacheDirectoryMetadata& aDirectoryMetadata, + const int64_t aUpdatingSize) { + MOZ_DIAGNOSTIC_ASSERT(aUpdatingSize > 0); + + QuotaManager* quotaManager = QuotaManager::Get(); + MOZ_DIAGNOSTIC_ASSERT(quotaManager); + + quotaManager->DecreaseUsageForClient( + quota::ClientMetadata{aDirectoryMetadata, Client::DOMCACHE}, + aUpdatingSize); +} + +bool DirectoryPaddingFileExists(nsIFile& aBaseDir, + DirPaddingFile aPaddingFileType) { + QM_TRY_INSPECT( + const auto& file, + CloneFileAndAppend(aBaseDir, aPaddingFileType == DirPaddingFile::TMP_FILE + ? nsLiteralString(PADDING_TMP_FILE_NAME) + : nsLiteralString(PADDING_FILE_NAME)), + false); + + QM_TRY_RETURN(MOZ_TO_RESULT_INVOKE_MEMBER(file, Exists), false); +} + +Result<int64_t, nsresult> DirectoryPaddingGet(nsIFile& aBaseDir) { + MOZ_DIAGNOSTIC_ASSERT( + !DirectoryPaddingFileExists(aBaseDir, DirPaddingFile::TMP_FILE)); + + QM_TRY_INSPECT( + const auto& file, + CloneFileAndAppend(aBaseDir, nsLiteralString(PADDING_FILE_NAME))); + + QM_TRY_UNWRAP(auto stream, NS_NewLocalFileInputStream(file)); + + QM_TRY_INSPECT(const auto& bufferedStream, + NS_NewBufferedInputStream(stream.forget(), 512)); + + const nsCOMPtr<nsIObjectInputStream> objectStream = + NS_NewObjectInputStream(bufferedStream); + + QM_TRY_RETURN(MOZ_TO_RESULT_INVOKE_MEMBER(objectStream, Read64) + .map([](const uint64_t val) { return int64_t(val); })); +} + +nsresult DirectoryPaddingInit(nsIFile& aBaseDir) { + QM_TRY( + MOZ_TO_RESULT(DirectoryPaddingWrite(aBaseDir, DirPaddingFile::FILE, 0))); + + return NS_OK; +} + +nsresult UpdateDirectoryPaddingFile(nsIFile& aBaseDir, + mozIStorageConnection& aConn, + const int64_t aIncreaseSize, + const int64_t aDecreaseSize, + const bool aTemporaryFileExist) { + MOZ_DIAGNOSTIC_ASSERT(aIncreaseSize >= 0); + MOZ_DIAGNOSTIC_ASSERT(aDecreaseSize >= 0); + + const auto directoryPaddingGetResult = + aTemporaryFileExist ? Maybe<int64_t>{} : [&aBaseDir] { + QM_TRY_RETURN(QM_OR_ELSE_WARN_IF( + // Expression. + DirectoryPaddingGet(aBaseDir).map(Some<int64_t>), + // Predicate. + IsFileNotFoundError, + // Fallback. + ErrToDefaultOk<Maybe<int64_t>>), + Maybe<int64_t>{}); + }(); + + QM_TRY_INSPECT( + const int64_t& currentPaddingSize, + ([directoryPaddingGetResult, &aBaseDir, &aConn, aIncreaseSize, + aDecreaseSize]() -> Result<int64_t, nsresult> { + if (!directoryPaddingGetResult) { + // Fail to read padding size from the dir padding file, so try to + // restore. + + // Not delete the temporary padding file here, because we're going + // to overwrite it below anyway. + QM_TRY(MOZ_TO_RESULT( + DirectoryPaddingDeleteFile(aBaseDir, DirPaddingFile::FILE))); + + // We don't need to add the aIncreaseSize or aDecreaseSize here, + // because it's already encompassed within the database. + QM_TRY_RETURN(db::FindOverallPaddingSize(aConn)); + } + + int64_t currentPaddingSize = directoryPaddingGetResult.value(); + bool shouldRevise = false; + + if (aIncreaseSize > 0) { + if (INT64_MAX - currentPaddingSize < aDecreaseSize) { + shouldRevise = true; + } else { + currentPaddingSize += aIncreaseSize; + } + } + + if (aDecreaseSize > 0) { + if (currentPaddingSize < aDecreaseSize) { + shouldRevise = true; + } else if (!shouldRevise) { + currentPaddingSize -= aDecreaseSize; + } + } + + if (shouldRevise) { + // If somehow runing into this condition, the tracking padding size is + // incorrect. + // Delete padding file to indicate the padding size is incorrect for + // avoiding error happening in the following lines. + QM_TRY(MOZ_TO_RESULT( + DirectoryPaddingDeleteFile(aBaseDir, DirPaddingFile::FILE))); + + QM_TRY_UNWRAP(currentPaddingSize, db::FindOverallPaddingSize(aConn)); + + // XXXtt: we should have an easy way to update (increase or + // recalulate) padding size in the QM. For now, only correct the + // padding size in padding file and make QM be able to get the correct + // size in the next QM initialization. We still want to catch this in + // the debug build. + MOZ_ASSERT(false, "The padding size is unsync with QM"); + } + +#ifdef DEBUG + const int64_t lastPaddingSize = currentPaddingSize; + QM_TRY_UNWRAP(currentPaddingSize, db::FindOverallPaddingSize(aConn)); + + MOZ_DIAGNOSTIC_ASSERT(currentPaddingSize == lastPaddingSize); +#endif // DEBUG + + return currentPaddingSize; + }())); + + MOZ_DIAGNOSTIC_ASSERT(currentPaddingSize >= 0); + + QM_TRY(MOZ_TO_RESULT(DirectoryPaddingWrite(aBaseDir, DirPaddingFile::TMP_FILE, + currentPaddingSize))); + + return NS_OK; +} + +nsresult DirectoryPaddingFinalizeWrite(nsIFile& aBaseDir) { + MOZ_DIAGNOSTIC_ASSERT( + DirectoryPaddingFileExists(aBaseDir, DirPaddingFile::TMP_FILE)); + + QM_TRY_INSPECT( + const auto& file, + CloneFileAndAppend(aBaseDir, nsLiteralString(PADDING_TMP_FILE_NAME))); + + QM_TRY(MOZ_TO_RESULT( + file->RenameTo(nullptr, nsLiteralString(PADDING_FILE_NAME)))); + + return NS_OK; +} + +Result<int64_t, nsresult> DirectoryPaddingRestore(nsIFile& aBaseDir, + mozIStorageConnection& aConn, + const bool aMustRestore) { + // The content of padding file is untrusted, so remove it here. + QM_TRY(MOZ_TO_RESULT( + DirectoryPaddingDeleteFile(aBaseDir, DirPaddingFile::FILE))); + + QM_TRY_INSPECT(const int64_t& paddingSize, db::FindOverallPaddingSize(aConn)); + MOZ_DIAGNOSTIC_ASSERT(paddingSize >= 0); + + QM_TRY(MOZ_TO_RESULT(DirectoryPaddingWrite(aBaseDir, DirPaddingFile::FILE, + paddingSize)), + (aMustRestore ? Err(tryTempError) + : Result<int64_t, nsresult>{paddingSize})); + + QM_TRY(MOZ_TO_RESULT( + DirectoryPaddingDeleteFile(aBaseDir, DirPaddingFile::TMP_FILE))); + + return paddingSize; +} + +nsresult DirectoryPaddingDeleteFile(nsIFile& aBaseDir, + DirPaddingFile aPaddingFileType) { + QM_TRY_INSPECT( + const auto& file, + CloneFileAndAppend(aBaseDir, aPaddingFileType == DirPaddingFile::TMP_FILE + ? nsLiteralString(PADDING_TMP_FILE_NAME) + : nsLiteralString(PADDING_FILE_NAME))); + + QM_TRY(QM_OR_ELSE_WARN_IF( + // Expression. + MOZ_TO_RESULT(file->Remove(/* recursive */ false)), + // Predicate. + IsFileNotFoundError, + // Fallback. + ErrToDefaultOk<>)); + + return NS_OK; +} +} // namespace mozilla::dom::cache |