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| 1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. | |
| 2 // Use of this source code is governed by a BSD-style license that can be | |
| 3 // found in the LICENSE file. | |
| 4 | |
| 5 #ifndef CONTENT_PUBLIC_BROWSER_TRACE_CONTROLLER_H_ | |
| 6 #define CONTENT_PUBLIC_BROWSER_TRACE_CONTROLLER_H_ | |
| 7 | |
| 8 #include "base/debug/trace_event.h" | |
| 9 #include "content/common/content_export.h" | |
| 10 | |
| 11 namespace content { | |
| 12 | |
| 13 class TraceSubscriber; | |
| 14 | |
| 15 // Note: TraceController is going to be deprecated and replaced with | |
| 16 // TracingController. | |
| 17 // | |
| 18 // TraceController is used on the browser processes to enable/disable | |
| 19 // trace status and collect trace data. Only the browser UI thread is allowed | |
| 20 // to interact with the TraceController object. All calls on the TraceSubscriber | |
| 21 // happen on the UI thread. | |
| 22 class TraceController { | |
| 23 public: | |
| 24 CONTENT_EXPORT static TraceController* GetInstance(); | |
| 25 | |
| 26 // Called by browser process to start tracing events on all processes. | |
| 27 // | |
| 28 // Currently only one subscriber is allowed at a time. | |
| 29 // Tracing begins immediately locally, and asynchronously on child processes | |
| 30 // as soon as they receive the BeginTracing request. | |
| 31 // | |
| 32 // If BeginTracing was already called previously, | |
| 33 // or if an EndTracingAsync is pending, | |
| 34 // or if another subscriber is tracing, | |
| 35 // BeginTracing will return false meaning it failed. | |
| 36 // | |
| 37 // |category_patterns| is a comma-delimited list of category wildcards. | |
| 38 // A category pattern can have an optional '-' prefix to exclude category | |
| 39 // groups that contain a matching category. | |
| 40 // All the same rules apply above, so for example, having both included and | |
| 41 // excluded category patterns in the same list would not be supported. | |
| 42 // | |
| 43 // |mode| is the tracing mode being used. | |
| 44 // | |
| 45 // Example: BeginTracing("test_MyTest*"); | |
| 46 // Example: BeginTracing("test_MyTest*,test_OtherStuff"); | |
| 47 // Example: BeginTracing("-excluded_category1,-excluded_category2"); | |
| 48 virtual bool BeginTracing(TraceSubscriber* subscriber, | |
| 49 const std::string& category_patterns, | |
| 50 base::debug::TraceLog::Options options) = 0; | |
| 51 | |
| 52 // Called by browser process to stop tracing events on all processes. | |
| 53 // | |
| 54 // Child processes typically are caching trace data and only rarely flush | |
| 55 // and send trace data back to the browser process. That is because it may be | |
| 56 // an expensive operation to send the trace data over IPC, and we would like | |
| 57 // to avoid much runtime overhead of tracing. So, to end tracing, we must | |
| 58 // asynchronously ask all child processes to flush any pending trace data. | |
| 59 // | |
| 60 // Once all child processes have acked the EndTracing request, | |
| 61 // TraceSubscriber will be called with OnEndTracingComplete. | |
| 62 // | |
| 63 // If a previous call to EndTracingAsync is already pending, | |
| 64 // or if another subscriber is tracing, | |
| 65 // EndTracingAsync will return false meaning it failed. | |
| 66 virtual bool EndTracingAsync(TraceSubscriber* subscriber) = 0; | |
| 67 | |
| 68 // Get the maximum across processes of trace buffer percent full state. | |
| 69 // When the TraceBufferPercentFull value is determined, | |
| 70 // subscriber->OnTraceBufferPercentFullReply is called. | |
| 71 // When any child process reaches 100% full, the TraceController will end | |
| 72 // tracing, and call TraceSubscriber::OnEndTracingComplete. | |
| 73 // GetTraceBufferPercentFullAsync fails in the following conditions: | |
| 74 // trace is ending or disabled; | |
| 75 // a previous call to GetTraceBufferPercentFullAsync is pending; or | |
| 76 // the caller is not the current subscriber. | |
| 77 virtual bool GetTraceBufferPercentFullAsync(TraceSubscriber* subscriber) = 0; | |
| 78 | |
| 79 // |subscriber->OnEventWatchNotification()| will be called every time the | |
| 80 // given event occurs on any process. | |
| 81 virtual bool SetWatchEvent(TraceSubscriber* subscriber, | |
| 82 const std::string& category_name, | |
| 83 const std::string& event_name) = 0; | |
| 84 | |
| 85 // Cancel the watch event. If tracing is enabled, this may race with the | |
| 86 // watch event notification firing. | |
| 87 virtual bool CancelWatchEvent(TraceSubscriber* subscriber) = 0; | |
| 88 | |
| 89 // Cancel the subscriber so that it will not be called when EndTracingAsync is | |
| 90 // acked by all child processes. This will also call EndTracingAsync | |
| 91 // internally if necessary. | |
| 92 // Safe to call even if caller is not the current subscriber. | |
| 93 virtual void CancelSubscriber(TraceSubscriber* subscriber) = 0; | |
| 94 | |
| 95 // Get set of known category groups. This can change as new code paths are | |
| 96 // reached. If true is returned, subscriber->OnKnownCategoriesCollected will | |
| 97 // be called once the categories are retrieved from child processes. | |
| 98 virtual bool GetKnownCategoryGroupsAsync(TraceSubscriber* subscriber) = 0; | |
| 99 | |
| 100 protected: | |
| 101 virtual ~TraceController() {} | |
| 102 }; | |
| 103 | |
| 104 } // namespace content | |
| 105 | |
| 106 #endif // CONTENT_PUBLIC_BROWSER_TRACE_CONTROLLER_H_ | |
| 107 | |
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