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// Copyright 2015 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef BASE_FILES_FILE_TRACING_H_
#define BASE_FILES_FILE_TRACING_H_
#include <stdint.h>
#include "base/base_export.h"
#include "base/memory/raw_ptr.h"
#define FILE_TRACING_PREFIX "File"
#define SCOPED_FILE_TRACE_WITH_SIZE(name, size) \
FileTracing::ScopedTrace scoped_file_trace; \
if (FileTracing::IsCategoryEnabled()) \
scoped_file_trace.Initialize(FILE_TRACING_PREFIX "::" name, this, size)
#define SCOPED_FILE_TRACE(name) SCOPED_FILE_TRACE_WITH_SIZE(name, 0)
namespace base {
class File;
class FilePath;
class BASE_EXPORT FileTracing {
public:
// Whether the file tracing category is enabled.
static bool IsCategoryEnabled();
class Provider {
public:
virtual ~Provider() = default;
// Whether the file tracing category is currently enabled.
virtual bool FileTracingCategoryIsEnabled() const = 0;
// Enables file tracing for |id|. Must be called before recording events.
virtual void FileTracingEnable(const void* id) = 0;
// Disables file tracing for |id|.
virtual void FileTracingDisable(const void* id) = 0;
// Begins an event for |id| with |name|. |path| tells where in the directory
// structure the event is happening (and may be blank). |size| is the number
// of bytes involved in the event.
virtual void FileTracingEventBegin(const char* name,
const void* id,
const FilePath& path,
int64_t size) = 0;
// Ends an event for |id| with |name|.
virtual void FileTracingEventEnd(const char* name, const void* id) = 0;
};
// Sets a global file tracing provider to query categories and record events.
static void SetProvider(Provider* provider);
// Enables file tracing while in scope.
class ScopedEnabler {
public:
ScopedEnabler();
~ScopedEnabler();
};
class ScopedTrace {
public:
ScopedTrace() = default;
ScopedTrace(const ScopedTrace&) = delete;
ScopedTrace& operator=(const ScopedTrace&) = delete;
~ScopedTrace();
// Called only if the tracing category is enabled. |name| is the name of the
// event to trace (e.g. "Read", "Write") and must have an application
// lifetime (e.g. static or literal). |file| is the file being traced; must
// outlive this class. |size| is the size (in bytes) of this event.
void Initialize(const char* name, const File* file, int64_t size);
private:
// The ID of this trace. Based on the |file| passed to |Initialize()|. Must
// outlive this class.
raw_ptr<const void> id_ = nullptr;
// The name of the event to trace (e.g. "Read", "Write"). Prefixed with
// "File".
const char* name_;
};
FileTracing(const FileTracing&) = delete;
FileTracing& operator=(const FileTracing&) = delete;
};
} // namespace base
#endif // BASE_FILES_FILE_TRACING_H_