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-rw-r--r--webrtc/rtc_base/event_tracer.cc412
1 files changed, 412 insertions, 0 deletions
diff --git a/webrtc/rtc_base/event_tracer.cc b/webrtc/rtc_base/event_tracer.cc
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+++ b/webrtc/rtc_base/event_tracer.cc
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+/*
+ * Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ * Use of this source code is governed by a BSD-style license
+ * that can be found in the LICENSE file in the root of the source
+ * tree. An additional intellectual property rights grant can be found
+ * in the file PATENTS. All contributing project authors may
+ * be found in the AUTHORS file in the root of the source tree.
+ */
+#include "rtc_base/event_tracer.h"
+
+#include <inttypes.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+
+#include <string>
+#include <vector>
+
+#include "rtc_base/atomic_ops.h"
+#include "rtc_base/checks.h"
+#include "rtc_base/event.h"
+#include "rtc_base/logging.h"
+#include "rtc_base/platform_thread.h"
+#include "rtc_base/platform_thread_types.h"
+#include "rtc_base/synchronization/mutex.h"
+#include "rtc_base/thread_annotations.h"
+#include "rtc_base/thread_checker.h"
+#include "rtc_base/time_utils.h"
+#include "rtc_base/trace_event.h"
+
+// This is a guesstimate that should be enough in most cases.
+static const size_t kEventLoggerArgsStrBufferInitialSize = 256;
+static const size_t kTraceArgBufferLength = 32;
+
+namespace webrtc {
+
+namespace {
+
+GetCategoryEnabledPtr g_get_category_enabled_ptr = nullptr;
+AddTraceEventPtr g_add_trace_event_ptr = nullptr;
+
+} // namespace
+
+void SetupEventTracer(GetCategoryEnabledPtr get_category_enabled_ptr,
+ AddTraceEventPtr add_trace_event_ptr) {
+ g_get_category_enabled_ptr = get_category_enabled_ptr;
+ g_add_trace_event_ptr = add_trace_event_ptr;
+}
+
+const unsigned char* EventTracer::GetCategoryEnabled(const char* name) {
+ if (g_get_category_enabled_ptr)
+ return g_get_category_enabled_ptr(name);
+
+ // A string with null terminator means category is disabled.
+ return reinterpret_cast<const unsigned char*>("\0");
+}
+
+// Arguments to this function (phase, etc.) are as defined in
+// webrtc/rtc_base/trace_event.h.
+void EventTracer::AddTraceEvent(char phase,
+ const unsigned char* category_enabled,
+ const char* name,
+ unsigned long long id,
+ int num_args,
+ const char** arg_names,
+ const unsigned char* arg_types,
+ const unsigned long long* arg_values,
+ unsigned char flags) {
+ if (g_add_trace_event_ptr) {
+ g_add_trace_event_ptr(phase, category_enabled, name, id, num_args,
+ arg_names, arg_types, arg_values, flags);
+ }
+}
+
+} // namespace webrtc
+
+namespace rtc {
+namespace tracing {
+namespace {
+
+static void EventTracingThreadFunc(void* params);
+
+// Atomic-int fast path for avoiding logging when disabled.
+static volatile int g_event_logging_active = 0;
+
+// TODO(pbos): Log metadata for all threads, etc.
+class EventLogger final {
+ public:
+ EventLogger()
+ : logging_thread_(EventTracingThreadFunc,
+ this,
+ "EventTracingThread",
+ kLowPriority) {}
+ ~EventLogger() { RTC_DCHECK(thread_checker_.IsCurrent()); }
+
+ void AddTraceEvent(const char* name,
+ const unsigned char* category_enabled,
+ char phase,
+ int num_args,
+ const char** arg_names,
+ const unsigned char* arg_types,
+ const unsigned long long* arg_values,
+ uint64_t timestamp,
+ int pid,
+ rtc::PlatformThreadId thread_id) {
+ std::vector<TraceArg> args(num_args);
+ for (int i = 0; i < num_args; ++i) {
+ TraceArg& arg = args[i];
+ arg.name = arg_names[i];
+ arg.type = arg_types[i];
+ arg.value.as_uint = arg_values[i];
+
+ // Value is a pointer to a temporary string, so we have to make a copy.
+ if (arg.type == TRACE_VALUE_TYPE_COPY_STRING) {
+ // Space for the string and for the terminating null character.
+ size_t str_length = strlen(arg.value.as_string) + 1;
+ char* str_copy = new char[str_length];
+ memcpy(str_copy, arg.value.as_string, str_length);
+ arg.value.as_string = str_copy;
+ }
+ }
+ webrtc::MutexLock lock(&mutex_);
+ trace_events_.push_back(
+ {name, category_enabled, phase, args, timestamp, 1, thread_id});
+ }
+
+ // The TraceEvent format is documented here:
+ // https://docs.google.com/document/d/1CvAClvFfyA5R-PhYUmn5OOQtYMH4h6I0nSsKchNAySU/preview
+ void Log() {
+ RTC_DCHECK(output_file_);
+ static const int kLoggingIntervalMs = 100;
+ fprintf(output_file_, "{ \"traceEvents\": [\n");
+ bool has_logged_event = false;
+ while (true) {
+ bool shutting_down = shutdown_event_.Wait(kLoggingIntervalMs);
+ std::vector<TraceEvent> events;
+ {
+ webrtc::MutexLock lock(&mutex_);
+ trace_events_.swap(events);
+ }
+ std::string args_str;
+ args_str.reserve(kEventLoggerArgsStrBufferInitialSize);
+ for (TraceEvent& e : events) {
+ args_str.clear();
+ if (!e.args.empty()) {
+ args_str += ", \"args\": {";
+ bool is_first_argument = true;
+ for (TraceArg& arg : e.args) {
+ if (!is_first_argument)
+ args_str += ",";
+ is_first_argument = false;
+ args_str += " \"";
+ args_str += arg.name;
+ args_str += "\": ";
+ args_str += TraceArgValueAsString(arg);
+
+ // Delete our copy of the string.
+ if (arg.type == TRACE_VALUE_TYPE_COPY_STRING) {
+ delete[] arg.value.as_string;
+ arg.value.as_string = nullptr;
+ }
+ }
+ args_str += " }";
+ }
+ fprintf(output_file_,
+ "%s{ \"name\": \"%s\""
+ ", \"cat\": \"%s\""
+ ", \"ph\": \"%c\""
+ ", \"ts\": %" PRIu64
+ ", \"pid\": %d"
+#if defined(WEBRTC_WIN)
+ ", \"tid\": %lu"
+#else
+ ", \"tid\": %d"
+#endif // defined(WEBRTC_WIN)
+ "%s"
+ "}\n",
+ has_logged_event ? "," : " ", e.name, e.category_enabled,
+ e.phase, e.timestamp, e.pid, e.tid, args_str.c_str());
+ has_logged_event = true;
+ }
+ if (shutting_down)
+ break;
+ }
+ fprintf(output_file_, "]}\n");
+ if (output_file_owned_)
+ fclose(output_file_);
+ output_file_ = nullptr;
+ }
+
+ void Start(FILE* file, bool owned) {
+ RTC_DCHECK(thread_checker_.IsCurrent());
+ RTC_DCHECK(file);
+ RTC_DCHECK(!output_file_);
+ output_file_ = file;
+ output_file_owned_ = owned;
+ {
+ webrtc::MutexLock lock(&mutex_);
+ // Since the atomic fast-path for adding events to the queue can be
+ // bypassed while the logging thread is shutting down there may be some
+ // stale events in the queue, hence the vector needs to be cleared to not
+ // log events from a previous logging session (which may be days old).
+ trace_events_.clear();
+ }
+ // Enable event logging (fast-path). This should be disabled since starting
+ // shouldn't be done twice.
+ RTC_CHECK_EQ(0,
+ rtc::AtomicOps::CompareAndSwap(&g_event_logging_active, 0, 1));
+
+ // Finally start, everything should be set up now.
+ logging_thread_.Start();
+ TRACE_EVENT_INSTANT0("webrtc", "EventLogger::Start");
+ }
+
+ void Stop() {
+ RTC_DCHECK(thread_checker_.IsCurrent());
+ TRACE_EVENT_INSTANT0("webrtc", "EventLogger::Stop");
+ // Try to stop. Abort if we're not currently logging.
+ if (rtc::AtomicOps::CompareAndSwap(&g_event_logging_active, 1, 0) == 0)
+ return;
+
+ // Wake up logging thread to finish writing.
+ shutdown_event_.Set();
+ // Join the logging thread.
+ logging_thread_.Stop();
+ }
+
+ private:
+ struct TraceArg {
+ const char* name;
+ unsigned char type;
+ // Copied from webrtc/rtc_base/trace_event.h TraceValueUnion.
+ union TraceArgValue {
+ bool as_bool;
+ unsigned long long as_uint;
+ long long as_int;
+ double as_double;
+ const void* as_pointer;
+ const char* as_string;
+ } value;
+
+ // Assert that the size of the union is equal to the size of the as_uint
+ // field since we are assigning to arbitrary types using it.
+ static_assert(sizeof(TraceArgValue) == sizeof(unsigned long long),
+ "Size of TraceArg value union is not equal to the size of "
+ "the uint field of that union.");
+ };
+
+ struct TraceEvent {
+ const char* name;
+ const unsigned char* category_enabled;
+ char phase;
+ std::vector<TraceArg> args;
+ uint64_t timestamp;
+ int pid;
+ rtc::PlatformThreadId tid;
+ };
+
+ static std::string TraceArgValueAsString(TraceArg arg) {
+ std::string output;
+
+ if (arg.type == TRACE_VALUE_TYPE_STRING ||
+ arg.type == TRACE_VALUE_TYPE_COPY_STRING) {
+ // Space for every character to be an espaced character + two for
+ // quatation marks.
+ output.reserve(strlen(arg.value.as_string) * 2 + 2);
+ output += '\"';
+ const char* c = arg.value.as_string;
+ do {
+ if (*c == '"' || *c == '\\') {
+ output += '\\';
+ output += *c;
+ } else {
+ output += *c;
+ }
+ } while (*++c);
+ output += '\"';
+ } else {
+ output.resize(kTraceArgBufferLength);
+ size_t print_length = 0;
+ switch (arg.type) {
+ case TRACE_VALUE_TYPE_BOOL:
+ if (arg.value.as_bool) {
+ strcpy(&output[0], "true");
+ print_length = 4;
+ } else {
+ strcpy(&output[0], "false");
+ print_length = 5;
+ }
+ break;
+ case TRACE_VALUE_TYPE_UINT:
+ print_length = snprintf(&output[0], kTraceArgBufferLength, "%llu",
+ arg.value.as_uint);
+ break;
+ case TRACE_VALUE_TYPE_INT:
+ print_length = snprintf(&output[0], kTraceArgBufferLength, "%lld",
+ arg.value.as_int);
+ break;
+ case TRACE_VALUE_TYPE_DOUBLE:
+ print_length = snprintf(&output[0], kTraceArgBufferLength, "%f",
+ arg.value.as_double);
+ break;
+ case TRACE_VALUE_TYPE_POINTER:
+ print_length = snprintf(&output[0], kTraceArgBufferLength, "\"%p\"",
+ arg.value.as_pointer);
+ break;
+ }
+ size_t output_length = print_length < kTraceArgBufferLength
+ ? print_length
+ : kTraceArgBufferLength - 1;
+ // This will hopefully be very close to nop. On most implementations, it
+ // just writes null byte and sets the length field of the string.
+ output.resize(output_length);
+ }
+
+ return output;
+ }
+
+ webrtc::Mutex mutex_;
+ std::vector<TraceEvent> trace_events_ RTC_GUARDED_BY(mutex_);
+ rtc::PlatformThread logging_thread_;
+ rtc::Event shutdown_event_;
+ rtc::ThreadChecker thread_checker_;
+ FILE* output_file_ = nullptr;
+ bool output_file_owned_ = false;
+};
+
+static void EventTracingThreadFunc(void* params) {
+ static_cast<EventLogger*>(params)->Log();
+}
+
+static EventLogger* volatile g_event_logger = nullptr;
+static const char* const kDisabledTracePrefix = TRACE_DISABLED_BY_DEFAULT("");
+const unsigned char* InternalGetCategoryEnabled(const char* name) {
+ const char* prefix_ptr = &kDisabledTracePrefix[0];
+ const char* name_ptr = name;
+ // Check whether name contains the default-disabled prefix.
+ while (*prefix_ptr == *name_ptr && *prefix_ptr != '\0') {
+ ++prefix_ptr;
+ ++name_ptr;
+ }
+ return reinterpret_cast<const unsigned char*>(*prefix_ptr == '\0' ? ""
+ : name);
+}
+
+void InternalAddTraceEvent(char phase,
+ const unsigned char* category_enabled,
+ const char* name,
+ unsigned long long id,
+ int num_args,
+ const char** arg_names,
+ const unsigned char* arg_types,
+ const unsigned long long* arg_values,
+ unsigned char flags) {
+ // Fast path for when event tracing is inactive.
+ if (rtc::AtomicOps::AcquireLoad(&g_event_logging_active) == 0)
+ return;
+
+ g_event_logger->AddTraceEvent(name, category_enabled, phase, num_args,
+ arg_names, arg_types, arg_values,
+ rtc::TimeMicros(), 1, rtc::CurrentThreadId());
+}
+
+} // namespace
+
+void SetupInternalTracer() {
+ RTC_CHECK(rtc::AtomicOps::CompareAndSwapPtr(
+ &g_event_logger, static_cast<EventLogger*>(nullptr),
+ new EventLogger()) == nullptr);
+ webrtc::SetupEventTracer(InternalGetCategoryEnabled, InternalAddTraceEvent);
+}
+
+void StartInternalCaptureToFile(FILE* file) {
+ if (g_event_logger) {
+ g_event_logger->Start(file, false);
+ }
+}
+
+bool StartInternalCapture(const char* filename) {
+ if (!g_event_logger)
+ return false;
+
+ FILE* file = fopen(filename, "w");
+ if (!file) {
+ RTC_LOG(LS_ERROR) << "Failed to open trace file '" << filename
+ << "' for writing.";
+ return false;
+ }
+ g_event_logger->Start(file, true);
+ return true;
+}
+
+void StopInternalCapture() {
+ if (g_event_logger) {
+ g_event_logger->Stop();
+ }
+}
+
+void ShutdownInternalTracer() {
+ StopInternalCapture();
+ EventLogger* old_logger = rtc::AtomicOps::AcquireLoadPtr(&g_event_logger);
+ RTC_DCHECK(old_logger);
+ RTC_CHECK(rtc::AtomicOps::CompareAndSwapPtr(
+ &g_event_logger, old_logger,
+ static_cast<EventLogger*>(nullptr)) == old_logger);
+ delete old_logger;
+ webrtc::SetupEventTracer(nullptr, nullptr);
+}
+
+} // namespace tracing
+} // namespace rtc