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// Copyright 2020 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef CONTENT_BROWSER_FONT_ACCESS_FONT_ENUMERATION_CACHE_H_
#define CONTENT_BROWSER_FONT_ACCESS_FONT_ENUMERATION_CACHE_H_
#include <memory>
#include <optional>
#include <string>
#include "base/memory/read_only_shared_memory_region.h"
#include "base/memory/scoped_refptr.h"
#include "base/sequence_checker.h"
#include "base/synchronization/atomic_flag.h"
#include "base/task/deferred_sequenced_task_runner.h"
#include "base/task/sequenced_task_runner.h"
#include "base/thread_annotations.h"
#include "base/threading/sequence_bound.h"
#include "base/types/pass_key.h"
#include "content/common/content_export.h"
#include "third_party/blink/public/common/font_access/font_enumeration_table.pb.h"
#include "third_party/blink/public/mojom/font_access/font_access.mojom.h"
namespace content {
class FontEnumerationDataSource;
struct CONTENT_EXPORT FontEnumerationData {
blink::mojom::FontEnumerationStatus status;
// Stores a serialized blink::FontEnumerationTable proto.
//
// Valid iff `status` is kOk.
base::ReadOnlySharedMemoryRegion font_data;
};
// Caches font enumeration data, and serves it as a ReadOnlySharedMemoryRegion.
//
// This class is not thread-safe. Each instance must be accessed from a single
// sequence, which must allow blocking.
class CONTENT_EXPORT FontEnumerationCache {
public:
// Factory method for production instances.
static base::SequenceBound<FontEnumerationCache> Create();
// Factory method with dependency injection support for testing.
//
// `task_runner` must allow blocking.
static base::SequenceBound<FontEnumerationCache> CreateForTesting(
scoped_refptr<base::SequencedTaskRunner> task_runner,
std::unique_ptr<FontEnumerationDataSource> data_source,
std::optional<std::string> locale_override);
// Exposed for base::SequenceBound. Instances must be obtained from one of
// the Create*() factory methods.
FontEnumerationCache(std::unique_ptr<FontEnumerationDataSource> data_source,
std::optional<std::string> locale_override,
base::PassKey<FontEnumerationCache>);
FontEnumerationCache(const FontEnumerationCache&) = delete;
FontEnumerationCache& operator=(const FontEnumerationCache&) = delete;
~FontEnumerationCache();
FontEnumerationData GetFontEnumerationData();
private:
// Build the cache given a properly formed enumeration cache table.
void BuildEnumerationCache(blink::FontEnumerationTable& table);
SEQUENCE_CHECKER(sequence_checker_);
// Guaranteed to be non-null.
const std::unique_ptr<FontEnumerationDataSource> data_source_
GUARDED_BY_CONTEXT(sequence_checker_);
// nullopt in production. Only set in testing.
const std::optional<std::string> locale_override_;
bool initialized_ GUARDED_BY_CONTEXT(sequence_checker_) = false;
// Valid only if `initialized_` is true.
FontEnumerationData data_ GUARDED_BY_CONTEXT(sequence_checker_);
};
} // namespace content
#endif // CONTENT_BROWSER_FONT_ACCESS_FONT_ENUMERATION_CACHE_H_
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