Revert of [Tracing] V8 Tracing Controller

src/libplatform/tracing/tracing-controller.cc

Index: src/libplatform/tracing/tracing-controller.cc
diff --git a/src/libplatform/tracing/tracing-controller.cc b/src/libplatform/tracing/tracing-controller.cc
deleted file mode 100644
index e9a21725e289fd565391084a0b933a00c82df407..0000000000000000000000000000000000000000
--- a/src/libplatform/tracing/tracing-controller.cc
+++ /dev/null
@@ -1,177 +0,0 @@
-// Copyright 2016 the V8 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.
-
-#include <stdio.h>
-#include <string.h>
-
-#include "include/libplatform/v8-tracing.h"
-
-#include "src/base/platform/mutex.h"
-
-namespace v8 {
-namespace platform {
-namespace tracing {
-
-#define MAX_CATEGORY_GROUPS 200
-
-// Parallel arrays g_category_groups and g_category_group_enabled are separate
-// so that a pointer to a member of g_category_group_enabled can be easily
-// converted to an index into g_category_groups. This allows macros to deal
-// only with char enabled pointers from g_category_group_enabled, and we can
-// convert internally to determine the category name from the char enabled
-// pointer.
-const char* g_category_groups[MAX_CATEGORY_GROUPS] = {
-    "toplevel", "tracing already shutdown",
-    "tracing categories exhausted; must increase MAX_CATEGORY_GROUPS",
-    "__metadata"};
-
-// The enabled flag is char instead of bool so that the API can be used from C.
-unsigned char g_category_group_enabled[MAX_CATEGORY_GROUPS] = {0};
-// Indexes here have to match the g_category_groups array indexes above.
-const int g_category_already_shutdown = 1;
-const int g_category_categories_exhausted = 2;
-// Metadata category not used in V8.
-// const int g_category_metadata = 3;
-const int g_num_builtin_categories = 4;
-
-// Skip default categories.
-v8::base::AtomicWord g_category_index = g_num_builtin_categories;
-
-void TracingController::Initialize(TraceBuffer* trace_buffer) {
-  trace_buffer_.reset(trace_buffer);
-}
-
-uint64_t TracingController::AddTraceEvent(
-    char phase, const uint8_t* category_enabled_flag, const char* name,
-    const char* scope, uint64_t id, uint64_t bind_id, int num_args,
-    const char** arg_names, const uint8_t* arg_types,
-    const uint64_t* arg_values, unsigned int flags) {
-  uint64_t handle;
-  TraceObject* trace_object = trace_buffer_->AddTraceEvent(&handle);
-  if (trace_object) {
-    trace_object->Initialize(phase, category_enabled_flag, name, scope, id,
-                             bind_id, num_args, arg_names, arg_types,
-                             arg_values, flags);
-  }
-  return handle;
-}
-
-void TracingController::UpdateTraceEventDuration(
-    const uint8_t* category_enabled_flag, const char* name, uint64_t handle) {
-  TraceObject* trace_object = trace_buffer_->GetEventByHandle(handle);
-  if (!trace_object) return;
-  trace_object->UpdateDuration();
-}
-
-const uint8_t* TracingController::GetCategoryGroupEnabled(
-    const char* category_group) {
-  if (!trace_buffer_) {
-    DCHECK(!g_category_group_enabled[g_category_already_shutdown]);
-    return &g_category_group_enabled[g_category_already_shutdown];
-  }
-  return GetCategoryGroupEnabledInternal(category_group);
-}
-
-const char* TracingController::GetCategoryGroupName(
-    const uint8_t* category_group_enabled) {
-  // Calculate the index of the category group by finding
-  // category_group_enabled in g_category_group_enabled array.
-  uintptr_t category_begin =
-      reinterpret_cast<uintptr_t>(g_category_group_enabled);
-  uintptr_t category_ptr = reinterpret_cast<uintptr_t>(category_group_enabled);
-  // Check for out of bounds category pointers.
-  DCHECK(category_ptr >= category_begin &&
-         category_ptr < reinterpret_cast<uintptr_t>(g_category_group_enabled +
-                                                    MAX_CATEGORY_GROUPS));
-  uintptr_t category_index =
-      (category_ptr - category_begin) / sizeof(g_category_group_enabled[0]);
-  return g_category_groups[category_index];
-}
-
-void TracingController::StartTracing(TraceConfig* trace_config) {
-  trace_config_.reset(trace_config);
-  mode_ = RECORDING_MODE;
-  UpdateCategoryGroupEnabledFlags();
-}
-
-void TracingController::StopTracing() {
-  mode_ = DISABLED;
-  UpdateCategoryGroupEnabledFlags();
-  trace_buffer_->Flush();
-}
-
-void TracingController::UpdateCategoryGroupEnabledFlag(size_t category_index) {
-  unsigned char enabled_flag = 0;
-  const char* category_group = g_category_groups[category_index];
-  if (mode_ == RECORDING_MODE &&
-      trace_config_->IsCategoryGroupEnabled(category_group)) {
-    enabled_flag |= ENABLED_FOR_RECORDING;
-  }
-
-  // TODO(fmeawad): EventCallback and ETW modes are not yet supported in V8.
-  // TODO(primiano): this is a temporary workaround for catapult:#2341,
-  // to guarantee that metadata events are always added even if the category
-  // filter is "-*". See crbug.com/618054 for more details and long-term fix.
-  if (mode_ == RECORDING_MODE && !strcmp(category_group, "__metadata")) {
-    enabled_flag |= ENABLED_FOR_RECORDING;
-  }
-
-  g_category_group_enabled[category_index] = enabled_flag;
-}
-
-void TracingController::UpdateCategoryGroupEnabledFlags() {
-  size_t category_index = base::NoBarrier_Load(&g_category_index);
-  for (size_t i = 0; i < category_index; i++) UpdateCategoryGroupEnabledFlag(i);
-}
-
-const uint8_t* TracingController::GetCategoryGroupEnabledInternal(
-    const char* category_group) {
-  // Check that category groups does not contain double quote
-  DCHECK(!strchr(category_group, '"'));
-
-  // The g_category_groups is append only, avoid using a lock for the fast path.
-  size_t current_category_index = v8::base::Acquire_Load(&g_category_index);
-
-  // Search for pre-existing category group.
-  for (size_t i = 0; i < current_category_index; ++i) {
-    if (strcmp(g_category_groups[i], category_group) == 0) {
-      return &g_category_group_enabled[i];
-    }
-  }
-
-  unsigned char* category_group_enabled = NULL;
-  size_t category_index = base::Acquire_Load(&g_category_index);
-  for (size_t i = 0; i < category_index; ++i) {
-    if (strcmp(g_category_groups[i], category_group) == 0) {
-      return &g_category_group_enabled[i];
-    }
-  }
-
-  // Create a new category group.
-  // Check that there is a slot for the new category_group.
-  DCHECK(category_index < MAX_CATEGORY_GROUPS);
-  if (category_index < MAX_CATEGORY_GROUPS) {
-    // Don't hold on to the category_group pointer, so that we can create
-    // category groups with strings not known at compile time (this is
-    // required by SetWatchEvent).
-    const char* new_group = strdup(category_group);
-    g_category_groups[category_index] = new_group;
-    DCHECK(!g_category_group_enabled[category_index]);
-    // Note that if both included and excluded patterns in the
-    // TraceConfig are empty, we exclude nothing,
-    // thereby enabling this category group.
-    UpdateCategoryGroupEnabledFlag(category_index);
-    category_group_enabled = &g_category_group_enabled[category_index];
-    // Update the max index now.
-    base::Release_Store(&g_category_index, category_index + 1);
-  } else {
-    category_group_enabled =
-        &g_category_group_enabled[g_category_categories_exhausted];
-  }
-  return category_group_enabled;
-}
-
-}  // namespace tracing
-}  // namespace platform
-}  // namespace v8