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gecko-dev/dom/cache/FileUtils.cpp

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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#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/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"
namespace mozilla::dom::cache {
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 ||
aRv == NS_ERROR_FILE_TARGET_DOES_NOT_EXIST;
}
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(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.
ToResult(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.
ToResult(bodyDir->Create(nsIFile::DIRECTORY_TYPE, 0755)),
// Predicate.
IsSpecificError<NS_ERROR_FILE_ALREADY_EXISTS>,
// Fallback.
ErrToDefaultOk<>));
return NS_OK;
}
nsresult BodyDeleteDir(const QuotaInfo& aQuotaInfo, nsIFile& aBaseDir) {
QM_TRY_INSPECT(const auto& bodyDir,
CloneFileAndAppend(aBaseDir, kMorgueDirectory));
QM_TRY(RemoveNsIFileRecursively(aQuotaInfo, *bodyDir));
return NS_OK;
}
Result<std::pair<nsID, nsCOMPtr<nsISupports>>, nsresult> BodyStartWriteStream(
const QuotaInfo& aQuotaInfo, nsIFile& aBaseDir, nsIInputStream& aSource,
void* aClosure, nsAsyncCopyCallbackFun aCallback) {
MOZ_DIAGNOSTIC_ASSERT(aClosure);
MOZ_DIAGNOSTIC_ASSERT(aCallback);
QM_TRY_INSPECT(const auto& idGen, ToResultGet<nsCOMPtr<nsIUUIDGenerator>>(
MOZ_SELECT_OVERLOAD(do_GetService),
"@mozilla.org/uuid-generator;1"));
nsID id;
QM_TRY(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(*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_INSPECT(const auto& fileStream,
CreateFileOutputStream(PERSISTENCE_TYPE_DEFAULT, aQuotaInfo,
Client::DOMCACHE, tmpFile.get()));
const auto compressed =
MakeRefPtr<SnappyCompressOutputStream>(fileStream.get());
const nsCOMPtr<nsIEventTarget> target =
do_GetService(NS_STREAMTRANSPORTSERVICE_CONTRACTID);
nsCOMPtr<nsISupports> copyContext;
QM_TRY(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(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(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(tmpFile->RenameTo(nullptr, finalFileName));
return NS_OK;
}
Result<NotNull<nsCOMPtr<nsIInputStream>>, nsresult> BodyOpen(
const QuotaInfo& aQuotaInfo, nsIFile& aBaseDir, const nsID& aId) {
QM_TRY_INSPECT(const auto& finalFile,
BodyIdToFile(aBaseDir, aId, BODY_FILE_FINAL));
QM_TRY_RETURN(CreateFileInputStream(PERSISTENCE_TYPE_DEFAULT, aQuotaInfo,
Client::DOMCACHE, finalFile.get())
.map([](NotNull<RefPtr<FileInputStream>>&& stream) {
return WrapNotNullUnchecked(
nsCOMPtr<nsIInputStream>{stream.get()});
}));
}
nsresult BodyMaybeUpdatePaddingSize(const QuotaInfo& aQuotaInfo,
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, aQuotaInfo, 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 QuotaInfo& aQuotaInfo, nsIFile& aBaseDir,
const nsTArray<nsID>& aIdList) {
for (const auto id : aIdList) {
QM_TRY_INSPECT(const auto& bodyDir, BodyGetCacheDir(aBaseDir, id));
const auto removeFileForId =
[&aQuotaInfo, &id](
nsIFile& bodyFile,
const nsACString& leafName) -> Result<bool, nsresult> {
nsID fileId;
QM_TRY(OkIf(fileId.Parse(leafName.BeginReading())), true,
([&aQuotaInfo, &bodyFile](const auto) {
DebugOnly<nsresult> result =
RemoveNsIFile(aQuotaInfo, bodyFile, /* aTrackQuota */ false);
MOZ_ASSERT(NS_SUCCEEDED(result));
}));
if (id.Equals(fileId)) {
DebugOnly<nsresult> result = RemoveNsIFile(aQuotaInfo, bodyFile);
MOZ_ASSERT(NS_SUCCEEDED(result));
return true;
}
return false;
};
QM_TRY(BodyTraverseFiles(aQuotaInfo, *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(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(objectStream->Write64(aPaddingSize));
return NS_OK;
}
} // namespace
nsresult BodyDeleteOrphanedFiles(const QuotaInfo& aQuotaInfo, 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,
[&aQuotaInfo, &aKnownBodyIdList](
const nsCOMPtr<nsIFile>& subdir) -> Result<Ok, nsresult> {
QM_TRY_INSPECT(const auto& dirEntryKind, GetDirEntryKind(*subdir));
switch (dirEntryKind) {
case nsIFileKind::ExistsAsDirectory: {
const auto removeOrphanedFiles =
[&aQuotaInfo, &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([&aQuotaInfo, &bodyFile] {
DebugOnly<nsresult> result =
RemoveNsIFile(aQuotaInfo, 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.
ToResult(BodyTraverseFiles(aQuotaInfo, *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(aQuotaInfo, *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 QuotaInfo& aQuotaInfo) {
QM_TRY_UNWRAP(auto marker, CloneFileAndAppend(*aQuotaInfo.mDir, u"cache"_ns));
QM_TRY(marker->Append(u"context_open.marker"_ns));
return marker;
}
} // namespace
nsresult CreateMarkerFile(const QuotaInfo& aQuotaInfo) {
QM_TRY_INSPECT(const auto& marker, GetMarkerFileHandle(aQuotaInfo));
// 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.
ToResult(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 QuotaInfo& aQuotaInfo) {
QM_TRY_INSPECT(const auto& marker, GetMarkerFileHandle(aQuotaInfo));
DebugOnly<nsresult> result =
RemoveNsIFile(aQuotaInfo, *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 QuotaInfo& aQuotaInfo) {
QM_TRY_INSPECT(const auto& marker, GetMarkerFileHandle(aQuotaInfo), false);
QM_TRY_RETURN(MOZ_TO_RESULT_INVOKE(marker, Exists), false);
}
nsresult RemoveNsIFileRecursively(const QuotaInfo& aQuotaInfo, nsIFile& aFile,
const bool aTrackQuota) {
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,
[&aQuotaInfo, &aTrackQuota](
const nsCOMPtr<nsIFile>& file) -> Result<Ok, nsresult> {
QM_TRY(RemoveNsIFileRecursively(aQuotaInfo, *file, aTrackQuota));
return Ok{};
}));
// In the end, remove the folder
QM_TRY(aFile.Remove(/* recursive */ false));
break;
case nsIFileKind::ExistsAsFile:
return RemoveNsIFile(aQuotaInfo, aFile, aTrackQuota);
case nsIFileKind::DoesNotExist:
// Ignore files that got removed externally while iterating.
break;
}
return NS_OK;
}
nsresult RemoveNsIFile(const QuotaInfo& aQuotaInfo, nsIFile& aFile,
const bool aTrackQuota) {
int64_t fileSize = 0;
if (aTrackQuota) {
QM_TRY_INSPECT(
const auto& maybeFileSize,
QM_OR_ELSE_WARN_IF(
// Expression.
MOZ_TO_RESULT_INVOKE(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.
ToResult(aFile.Remove(/* recursive */ false)),
// Predicate.
IsFileNotFoundError,
// Fallback.
ErrToDefaultOk<>));
if (fileSize > 0) {
MOZ_ASSERT(aTrackQuota);
DecreaseUsageForQuotaInfo(aQuotaInfo, fileSize);
}
return NS_OK;
}
void DecreaseUsageForQuotaInfo(const QuotaInfo& aQuotaInfo,
const int64_t aUpdatingSize) {
MOZ_DIAGNOSTIC_ASSERT(aUpdatingSize > 0);
QuotaManager* quotaManager = QuotaManager::Get();
MOZ_DIAGNOSTIC_ASSERT(quotaManager);
quotaManager->DecreaseUsageForClient(
quota::ClientMetadata{aQuotaInfo, 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(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(objectStream, Read64).map([](const uint64_t val) {
return int64_t(val);
}));
}
nsresult DirectoryPaddingInit(nsIFile& aBaseDir) {
QM_TRY(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(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(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(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(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(DirectoryPaddingDeleteFile(aBaseDir, DirPaddingFile::FILE));
QM_TRY_INSPECT(const int64_t& paddingSize, db::FindOverallPaddingSize(aConn));
MOZ_DIAGNOSTIC_ASSERT(paddingSize >= 0);
QM_TRY(DirectoryPaddingWrite(aBaseDir, DirPaddingFile::FILE, paddingSize),
(aMustRestore ? Err(tryTempError)
: Result<int64_t, nsresult>{paddingSize}));
QM_TRY(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.
ToResult(file->Remove(/* recursive */ false)),
// Predicate.
IsFileNotFoundError,
// Fallback.
ErrToDefaultOk<>));
return NS_OK;
}
} // namespace mozilla::dom::cache
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