Index: base/trace_event/category_registry.h |
diff --git a/base/trace_event/category_registry.h b/base/trace_event/category_registry.h |
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+++ b/base/trace_event/category_registry.h |
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+// Copyright 2016 The Chromium Authors. All rights reserved. |
+// Use of this source code is governed by a BSD-style license that can be |
+// found in the LICENSE file. |
+ |
+#ifndef BASE_TRACE_EVENT_CATEGORY_H_ |
+#define BASE_TRACE_EVENT_CATEGORY_H_ |
+ |
+#include <stddef.h> |
+#include <stdint.h> |
+ |
+#include "base/base_export.h" |
+#include "base/logging.h" |
+ |
+namespace base { |
+namespace trace_event { |
+ |
+struct TraceCategory; |
+class TraceCategoryTest; |
+class TraceLog; |
+ |
+// Keeps track of the state of all tracing categories. The reason why this |
+// is a fully static class with global state is to allow to statically define |
+// known categories as global linker-initialized structs, without requiring |
+// static initializers. |
+class BASE_EXPORT CategoryRegistry { |
+ public: |
+ // Allows for-each iterations over a slice of the categories array. |
+ class Range { |
+ public: |
+ Range(TraceCategory* begin, TraceCategory* end) : begin_(begin), end_(end) { |
+ DCHECK_LE(begin, end); |
+ } |
+ TraceCategory* begin() const { return begin_; } |
+ TraceCategory* end() const { return end_; } |
+ |
+ private: |
+ TraceCategory* const begin_; |
+ TraceCategory* const end_; |
+ }; |
+ |
+ // Known categories. |
+ static TraceCategory* const kCategoryExhausted; |
+ static TraceCategory* const kCategoryMetadata; |
+ static TraceCategory* const kCategoryAlreadyShutdown; |
+ |
+ // Returns a category entry from the Category.state_ptr() pointer. |
+ // TODO(primiano): trace macros should just keep a pointer to the entire |
+ // TraceCategory, not just the enabled state pointer. That would remove the |
+ // need for this function and make everything cleaner at no extra cost (as |
+ // long as the |state_| is the first field of the struct, which can be |
+ // guaranteed via static_assert, see TraceCategory ctor). |
+ static const TraceCategory* GetCategoryByStatePtr( |
+ const uint8_t* category_state); |
+ |
+ static bool IsBuiltinCategory(const TraceCategory*); |
+ |
+ private: |
+ friend class TraceCategoryTest; |
+ friend class TraceLog; |
+ |
+ // Only for debugging/testing purposes, is a no-op on release builds. |
+ static void Initialize(); |
+ |
+ // Resets the state of all categories, to clear up the state between tests. |
+ static void ResetForTesting(); |
+ |
+ // The output |category| argument is an undefinitely lived pointer to the |
+ // TraceCategory owned by the registry. TRACE_EVENTx macros will cache this |
+ // pointer and use it for checks in their fast-paths. |
+ // Returns false if the category was already present, true if the category |
+ // has just been added and hence requires initialization. |
+ static bool GetOrCreateCategoryByName(const char* category_name, |
+ TraceCategory** category); |
+ |
+ // Allows to iterate over the valid categories in a for-each loop. |
+ // This includes builtin categories such as __metadata. |
+ static Range GetAllCategories(); |
+}; |
+ |
+} // namespace trace_event |
+} // namespace base |
+ |
+#endif // BASE_TRACE_EVENT_CATEGORY_H_ |