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// Copyright 2018 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 "src/api.h"
#include "src/builtins/builtins-utils.h"
#include "src/builtins/builtins.h"
#include "src/counters.h"
#include "src/json-stringifier.h"
#include "src/objects-inl.h"
namespace v8 {
namespace internal {
namespace {
using v8::tracing::TracedValue;
#define MAX_STACK_LENGTH 100
class MaybeUtf8 {
public:
explicit MaybeUtf8(Isolate* isolate, Handle<String> string) : buf_(data_) {
string = String::Flatten(isolate, string);
int len;
if (string->IsOneByteRepresentation()) {
// Technically this allows unescaped latin1 characters but the trace
// events mechanism currently does the same and the current consuming
// tools are tolerant of it. A more correct approach here would be to
// escape non-ascii characters but this is easier and faster.
len = string->length();
AllocateSufficientSpace(len);
if (len > 0) {
// Why copy? Well, the trace event mechanism requires null-terminated
// strings, the bytes we get from SeqOneByteString are not. buf_ is
// guaranteed to be null terminated.
memcpy(buf_, Handle<SeqOneByteString>::cast(string)->GetChars(), len);
}
} else {
Local<v8::String> local = Utils::ToLocal(string);
len = local->Utf8Length();
AllocateSufficientSpace(len);
if (len > 0) {
local->WriteUtf8(reinterpret_cast<char*>(buf_));
}
}
buf_[len] = 0;
}
const char* operator*() const { return reinterpret_cast<const char*>(buf_); }
private:
void AllocateSufficientSpace(int len) {
if (len + 1 > MAX_STACK_LENGTH) {
allocated_.reset(new uint8_t[len + 1]);
buf_ = allocated_.get();
}
}
// In the most common cases, the buffer here will be stack allocated.
// A heap allocation will only occur if the data is more than MAX_STACK_LENGTH
// Given that this is used primarily for trace event categories and names,
// the MAX_STACK_LENGTH should be more than enough.
uint8_t* buf_;
uint8_t data_[MAX_STACK_LENGTH];
std::unique_ptr<uint8_t> allocated_;
};
class JsonTraceValue : public ConvertableToTraceFormat {
public:
explicit JsonTraceValue(Isolate* isolate, Handle<String> object) {
// object is a JSON string serialized using JSON.stringify() from within
// the BUILTIN(Trace) method. This may (likely) contain UTF8 values so
// to grab the appropriate buffer data we have to serialize it out. We
// hold on to the bits until the AppendAsTraceFormat method is called.
MaybeUtf8 data(isolate, object);
data_ = *data;
}
void AppendAsTraceFormat(std::string* out) const override { *out += data_; }
private:
std::string data_;
};
const uint8_t* GetCategoryGroupEnabled(Isolate* isolate,
Handle<String> string) {
MaybeUtf8 category(isolate, string);
return TRACE_EVENT_API_GET_CATEGORY_GROUP_ENABLED(*category);
}
#undef MAX_STACK_LENGTH
} // namespace
// Builins::kIsTraceCategoryEnabled(category) : bool
BUILTIN(IsTraceCategoryEnabled) {
HandleScope scope(isolate);
Handle<Object> category = args.atOrUndefined(isolate, 1);
if (!category->IsString()) {
THROW_NEW_ERROR_RETURN_FAILURE(
isolate, NewTypeError(MessageTemplate::kTraceEventCategoryError));
}
return isolate->heap()->ToBoolean(
*GetCategoryGroupEnabled(isolate, Handle<String>::cast(category)));
}
// Builtins::kTrace(phase, category, name, id, data) : bool
BUILTIN(Trace) {
HandleScope handle_scope(isolate);
Handle<Object> phase_arg = args.atOrUndefined(isolate, 1);
Handle<Object> category = args.atOrUndefined(isolate, 2);
Handle<Object> name_arg = args.atOrUndefined(isolate, 3);
Handle<Object> id_arg = args.atOrUndefined(isolate, 4);
Handle<Object> data_arg = args.atOrUndefined(isolate, 5);
const uint8_t* category_group_enabled =
GetCategoryGroupEnabled(isolate, Handle<String>::cast(category));
// Exit early if the category group is not enabled.
if (!*category_group_enabled) {
return ReadOnlyRoots(isolate).false_value();
}
if (!phase_arg->IsNumber()) {
THROW_NEW_ERROR_RETURN_FAILURE(
isolate, NewTypeError(MessageTemplate::kTraceEventPhaseError));
}
if (!category->IsString()) {
THROW_NEW_ERROR_RETURN_FAILURE(
isolate, NewTypeError(MessageTemplate::kTraceEventCategoryError));
}
if (!name_arg->IsString()) {
THROW_NEW_ERROR_RETURN_FAILURE(
isolate, NewTypeError(MessageTemplate::kTraceEventNameError));
}
uint32_t flags = TRACE_EVENT_FLAG_COPY;
int32_t id = 0;
if (!id_arg->IsNullOrUndefined(isolate)) {
if (!id_arg->IsNumber()) {
THROW_NEW_ERROR_RETURN_FAILURE(
isolate, NewTypeError(MessageTemplate::kTraceEventIDError));
}
flags |= TRACE_EVENT_FLAG_HAS_ID;
id = DoubleToInt32(id_arg->Number());
}
Handle<String> name_str = Handle<String>::cast(name_arg);
if (name_str->length() == 0) {
THROW_NEW_ERROR_RETURN_FAILURE(
isolate, NewTypeError(MessageTemplate::kTraceEventNameLengthError));
}
MaybeUtf8 name(isolate, name_str);
// We support passing one additional trace event argument with the
// name "data". Any JSON serializable value may be passed.
static const char* arg_name = "data";
int32_t num_args = 0;
uint8_t arg_type;
uint64_t arg_value;
if (!data_arg->IsUndefined(isolate)) {
// Serializes the data argument as a JSON string, which is then
// copied into an object. This eliminates duplicated code but
// could have perf costs. It is also subject to all the same
// limitations as JSON.stringify() as it relates to circular
// references and value limitations (e.g. BigInt is not supported).
JsonStringifier stringifier(isolate);
Handle<Object> result;
ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
isolate, result,
stringifier.Stringify(data_arg, isolate->factory()->undefined_value(),
isolate->factory()->undefined_value()));
std::unique_ptr<JsonTraceValue> traced_value;
traced_value.reset(
new JsonTraceValue(isolate, Handle<String>::cast(result)));
tracing::SetTraceValue(std::move(traced_value), &arg_type, &arg_value);
num_args++;
}
TRACE_EVENT_API_ADD_TRACE_EVENT(
static_cast<char>(DoubleToInt32(phase_arg->Number())),
category_group_enabled, *name, tracing::kGlobalScope, id, tracing::kNoId,
num_args, &arg_name, &arg_type, &arg_value, flags);
return ReadOnlyRoots(isolate).true_value();
}
} // namespace internal
} // namespace v8
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