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#include "node_internals.h"
#include "tracing/agent.h"
namespace node {
using v8::Context;
using v8::FunctionCallbackInfo;
using v8::Int32;
using v8::Local;
using v8::Object;
using v8::Value;
// The tracing APIs require category groups to be pointers to long-lived
// strings. Those strings are stored here.
static std::unordered_set<std::string> categoryGroups;
// Gets a pointer to the category-enabled flags for a tracing category group,
// if tracing is enabled for it.
static const uint8_t* GetCategoryGroupEnabled(const char* category_group) {
if (category_group == nullptr) return nullptr;
return TRACE_EVENT_API_GET_CATEGORY_GROUP_ENABLED(category_group);
}
static const char* GetCategoryGroup(Environment* env,
const Local<Value> categoryValue) {
CHECK(categoryValue->IsString());
Utf8Value category(env->isolate(), categoryValue);
// If the value already exists in the set, insertion.first will point
// to the existing value. Thus, this will maintain a long lived pointer
// to the category c-string.
auto insertion = categoryGroups.insert(category.out());
// The returned insertion is a pair whose first item is the object that was
// inserted or that blocked the insertion and second item is a boolean
// indicating whether it was inserted.
return insertion.first->c_str();
}
static void Emit(const FunctionCallbackInfo<Value>& args) {
Environment* env = Environment::GetCurrent(args);
Local<Context> context = env->context();
// Args: [type, category, name, id, argName, argValue]
CHECK_GE(args.Length(), 3);
// Check the category group first, to avoid doing more work if it's not
// enabled.
const char* category_group = GetCategoryGroup(env, args[1]);
const uint8_t* category_group_enabled =
GetCategoryGroupEnabled(category_group);
if (*category_group_enabled == 0) return;
// get trace_event phase
CHECK(args[0]->IsNumber());
char phase = static_cast<char>(args[0]->Int32Value(context).ToChecked());
// get trace_event name
CHECK(args[2]->IsString());
Utf8Value nameValue(env->isolate(), args[2]);
const char* name = nameValue.out();
// get trace_event id
int64_t id = 0;
bool has_id = false;
if (args.Length() >= 4 && !args[3]->IsUndefined() && !args[3]->IsNull()) {
has_id = true;
CHECK(args[3]->IsNumber());
id = args[3]->IntegerValue(context).ToChecked();
}
// TODO(AndreasMadsen): Two extra arguments are not supported.
// TODO(AndreasMadsen): String values are not supported.
int32_t num_args = 0;
const char* arg_names[1];
uint8_t arg_types[1];
uint64_t arg_values[1];
// Create Utf8Value in the function scope to prevent deallocation.
// The c-string will be copied by TRACE_EVENT_API_ADD_TRACE_EVENT at the end.
Utf8Value arg1NameValue(env->isolate(), args[4]);
if (args.Length() < 6 || (args[4]->IsUndefined() && args[5]->IsUndefined())) {
num_args = 0;
} else {
num_args = 1;
arg_types[0] = TRACE_VALUE_TYPE_INT;
CHECK(args[4]->IsString());
arg_names[0] = arg1NameValue.out();
CHECK(args[5]->IsNumber());
arg_values[0] = args[5]->IntegerValue(context).ToChecked();
}
// The TRACE_EVENT_FLAG_COPY flag indicates that the name and argument
// name should be copied thus they don't need to long-lived pointers.
// The category name still won't be copied and thus need to be a long-lived
// pointer.
uint32_t flags = TRACE_EVENT_FLAG_COPY;
if (has_id) {
flags |= TRACE_EVENT_FLAG_HAS_ID;
}
const char* scope = node::tracing::kGlobalScope;
uint64_t bind_id = node::tracing::kNoId;
TRACE_EVENT_API_ADD_TRACE_EVENT(
phase, category_group_enabled, name, scope, id, bind_id,
num_args, arg_names, arg_types, arg_values,
flags);
}
static void CategoryGroupEnabled(const FunctionCallbackInfo<Value>& args) {
Environment* env = Environment::GetCurrent(args);
const char* category_group = GetCategoryGroup(env, args[0]);
const uint8_t* category_group_enabled =
GetCategoryGroupEnabled(category_group);
args.GetReturnValue().Set(*category_group_enabled > 0);
}
void InitializeTraceEvents(Local<Object> target,
Local<Value> unused,
Local<Context> context,
void* priv) {
Environment* env = Environment::GetCurrent(context);
env->SetMethod(target, "emit", Emit);
env->SetMethod(target, "categoryGroupEnabled", CategoryGroupEnabled);
}
} // namespace node
NODE_BUILTIN_MODULE_CONTEXT_AWARE(trace_events, node::InitializeTraceEvents)
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