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content / browser / file_system_access / file_system_access_observer_host.cc [blame]
// Copyright 2023 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "content/browser/file_system_access/file_system_access_observer_host.h"
#include <memory>
#include "base/files/file_util.h"
#include "base/metrics/histogram_functions.h"
#include "base/ranges/algorithm.h"
#include "build/build_config.h"
#include "content/browser/file_system_access/file_system_access_directory_handle_impl.h"
#include "content/browser/file_system_access/file_system_access_error.h"
#include "content/browser/file_system_access/file_system_access_file_handle_impl.h"
#include "content/browser/file_system_access/file_system_access_manager_impl.h"
#include "content/browser/file_system_access/file_system_access_observer_observation.h"
#include "content/browser/file_system_access/file_system_access_transfer_token_impl.h"
#include "content/browser/file_system_access/file_system_access_watcher_manager.h"
#include "content/public/browser/file_system_access_permission_context.h"
#include "mojo/public/cpp/bindings/pending_receiver.h"
#include "storage/browser/file_system/file_system_operation_runner.h"
#include "storage/browser/file_system/file_system_url.h"
#include "third_party/blink/public/mojom/file_system_access/file_system_access_observer.mojom.h"
#include "third_party/blink/public/mojom/permissions/permission_status.mojom-shared.h"
namespace content {
using HandleType = FileSystemAccessPermissionContext::HandleType;
FileSystemAccessObserverHost::FileSystemAccessObserverHost(
FileSystemAccessManagerImpl* manager,
FileSystemAccessWatcherManager* watcher_manager,
const BindingContext& binding_context,
mojo::PendingReceiver<blink::mojom::FileSystemAccessObserverHost>
host_receiver)
: manager_(manager),
watcher_manager_(watcher_manager),
binding_context_(binding_context),
host_receiver_(this, std::move(host_receiver)) {
CHECK(manager_);
CHECK(watcher_manager_);
// `base::Unretained` is safe here because this instance owns
// `host_receiver_`.
host_receiver_.set_disconnect_handler(
base::BindOnce(&FileSystemAccessObserverHost::OnHostReceiverDisconnect,
base::Unretained(this)));
}
FileSystemAccessObserverHost::~FileSystemAccessObserverHost() {
DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
}
void FileSystemAccessObserverHost::Observe(
mojo::PendingRemote<blink::mojom::FileSystemAccessTransferToken> token,
bool is_recursive,
ObserveCallback callback) {
DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
CHECK(manager_);
manager_->ResolveTransferToken(
std::move(token),
base::BindOnce(
&FileSystemAccessObserverHost::DidResolveTransferTokenToObserve,
weak_factory_.GetWeakPtr(), is_recursive, std::move(callback)));
}
void FileSystemAccessObserverHost::DidResolveTransferTokenToObserve(
bool is_recursive,
ObserveCallback callback,
FileSystemAccessTransferTokenImpl* resolved_token) {
DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
if (!resolved_token) {
std::move(callback).Run(
file_system_access_error::FromStatus(
blink::mojom::FileSystemAccessStatus::kInvalidArgument),
mojo::NullReceiver());
return;
}
if (resolved_token->GetReadGrant()->GetStatus() !=
blink::mojom::PermissionStatus::GRANTED) {
std::move(callback).Run(
file_system_access_error::FromStatus(
blink::mojom::FileSystemAccessStatus::kPermissionDenied),
mojo::NullReceiver());
return;
}
FileSystemAccessPermissionContext::HandleType handle_type =
resolved_token->type();
absl::variant<std::unique_ptr<FileSystemAccessDirectoryHandleImpl>,
std::unique_ptr<FileSystemAccessFileHandleImpl>>
handle;
switch (handle_type) {
case FileSystemAccessPermissionContext::HandleType::kDirectory:
handle = resolved_token->CreateDirectoryHandle(binding_context());
break;
case FileSystemAccessPermissionContext::HandleType::kFile:
handle = resolved_token->CreateFileHandle(binding_context());
break;
}
// We only need to check if the path is a symlink or junction on local file
// system.
bool file_could_be_symlink =
resolved_token->url().type() == storage::kFileSystemTypeLocal;
#if BUILDFLAG(IS_FUCHSIA)
// Fuchsia does not support symlinks.
file_could_be_symlink = false;
#endif
if (!file_could_be_symlink) {
DidCheckIfSymlinkOrJunction(std::move(handle), std::move(callback),
resolved_token->url(), is_recursive,
handle_type, file_could_be_symlink);
return;
}
base::FilePath path = resolved_token->url().path();
base::ThreadPool::PostTaskAndReplyWithResult(
FROM_HERE, {base::MayBlock()},
base::BindOnce(
[](base::FilePath path) -> bool {
base::FilePath check_path;
// `base::NormalizeFilePath()` resolves any file path elements like
// symbolic links or junctions by returning the target file path.
if (!base::NormalizeFilePath(path, &check_path)) {
check_path = path;
}
DCHECK(path.empty() == check_path.empty());
return check_path != path;
},
std::move(path)),
base::BindOnce(&FileSystemAccessObserverHost::DidCheckIfSymlinkOrJunction,
weak_factory_.GetWeakPtr(), std::move(handle),
std::move(callback), resolved_token->url(), is_recursive,
handle_type));
}
void FileSystemAccessObserverHost::DidCheckIfSymlinkOrJunction(
absl::variant<std::unique_ptr<FileSystemAccessDirectoryHandleImpl>,
std::unique_ptr<FileSystemAccessFileHandleImpl>> handle,
ObserveCallback callback,
storage::FileSystemURL url,
bool is_recursive,
FileSystemAccessPermissionContext::HandleType handle_type,
bool is_symlink_or_junction) {
DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
if (url.type() == storage::kFileSystemTypeLocal) {
base::UmaHistogramBoolean(
"Storage.FileSystemAccess.AttemptToObserveSymlinkOrJunction",
is_symlink_or_junction);
}
// Observing symlink and junction is not supported for Origin Trial.
// TODO(crbug.com/363195541): Add support for symlinks and junctions for
// feature launch.
if (is_symlink_or_junction) {
std::move(callback).Run(
blink::mojom::FileSystemAccessError::New(
blink::mojom::FileSystemAccessStatus::kFileError,
base::File::FILE_ERROR_INVALID_OPERATION,
"Symlinks or junctions cannot be observed"),
mojo::NullReceiver());
return;
}
manager_->DoFileSystemOperation(
FROM_HERE,
handle_type == FileSystemAccessPermissionContext::HandleType::kDirectory
? &storage::FileSystemOperationRunner::DirectoryExists
: &storage::FileSystemOperationRunner::FileExists,
base::BindOnce(&FileSystemAccessObserverHost::DidCheckItemExists,
weak_factory_.GetWeakPtr(), std::move(handle),
std::move(callback), url, is_recursive),
url);
}
void FileSystemAccessObserverHost::DidCheckItemExists(
absl::variant<std::unique_ptr<FileSystemAccessDirectoryHandleImpl>,
std::unique_ptr<FileSystemAccessFileHandleImpl>> handle,
ObserveCallback callback,
storage::FileSystemURL url,
bool is_recursive,
base::File::Error result) {
DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
if (result != base::File::FILE_OK) {
std::move(callback).Run(file_system_access_error::FromFileError(result),
mojo::NullReceiver());
return;
}
switch (handle.index()) {
case 0u:
watcher_manager()->GetDirectoryObservation(
std::move(url), is_recursive,
base::BindOnce(&FileSystemAccessObserverHost::GotObservation,
weak_factory_.GetWeakPtr(), std::move(handle),
std::move(callback)));
break;
case 1u:
watcher_manager()->GetFileObservation(
std::move(url),
base::BindOnce(&FileSystemAccessObserverHost::GotObservation,
weak_factory_.GetWeakPtr(), std::move(handle),
std::move(callback)));
break;
}
}
void FileSystemAccessObserverHost::Unobserve(
mojo::PendingRemote<blink::mojom::FileSystemAccessTransferToken> token) {
DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
CHECK(manager_);
if (observations_.empty()) {
return;
}
manager_->ResolveTransferToken(
std::move(token),
base::BindOnce(
&FileSystemAccessObserverHost::DidResolveTransferTokenToUnobserve,
weak_factory_.GetWeakPtr()));
}
void FileSystemAccessObserverHost::DidResolveTransferTokenToUnobserve(
FileSystemAccessTransferTokenImpl* resolved_token) {
DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
if (!resolved_token) {
return;
}
// TODO(crbug.com/321980367): Better handle overlapping observations.
base::EraseIf(observations_, [&](const auto& observation) {
return observation->handle_url() == resolved_token->url();
});
}
void FileSystemAccessObserverHost::GotObservation(
absl::variant<std::unique_ptr<FileSystemAccessDirectoryHandleImpl>,
std::unique_ptr<FileSystemAccessFileHandleImpl>> handle,
ObserveCallback callback,
base::expected<std::unique_ptr<FileSystemAccessWatcherManager::Observation>,
blink::mojom::FileSystemAccessErrorPtr>
observation_or_error) {
DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
if (!observation_or_error.has_value()) {
std::move(callback).Run(std::move(observation_or_error.error()),
mojo::NullReceiver());
return;
}
mojo::PendingRemote<blink::mojom::FileSystemAccessObserver> observer_remote;
mojo::PendingReceiver<blink::mojom::FileSystemAccessObserver>
observer_receiver = observer_remote.InitWithNewPipeAndPassReceiver();
auto observer_observation =
std::make_unique<FileSystemAccessObserverObservation>(
this, std::move(observation_or_error.value()),
std::move(observer_remote), std::move(handle));
observations_.insert(std::move(observer_observation));
std::move(callback).Run(file_system_access_error::Ok(),
std::move(observer_receiver));
}
void FileSystemAccessObserverHost::RemoveObservation(
FileSystemAccessObserverObservation* observation) {
DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
size_t count_removed = observations_.erase(observation);
CHECK_EQ(count_removed, 1u);
}
void FileSystemAccessObserverHost::OnHostReceiverDisconnect() {
DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
observations_.clear();
host_receiver_.reset();
// Destroys `this`.
watcher_manager_->RemoveObserverHost(this);
}
} // namespace content