[해결] v8 javascript Engine Accessor 질문입니다.

// Copyright 2012 the V8 project authors. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
//     * Redistributions of source code must retain the above copyright
//       notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above
//       copyright notice, this list of conditions and the following
//       disclaimer in the documentation and/or other materials provided
//       with the distribution.
//     * Neither the name of Google Inc. nor the names of its
//       contributors may be used to endorse or promote products derived
//       from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
#include <include/v8.h>
 
#include <include/libplatform/libplatform.h>
 
#include <assert.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
 
/**
* This sample program shows how to implement a simple javascript shell
* based on V8.  This includes initializing V8 with command line options,
* creating global functions, compiling and executing strings.
*
* For a more sophisticated shell, consider using the debug shell D8.
*/
 
 
v8::Local<v8::Context> CreateShellContext(v8::Isolate* isolate);
void RunShell(v8::Local<v8::Context> context, v8::Platform* platform);
int RunMain(v8::Isolate* isolate, v8::Platform* platform, int argc,
	char* argv[]);
bool ExecuteString(v8::Isolate* isolate, v8::Local<v8::String> source,
	v8::Local<v8::Value> name, bool print_result,
	bool report_exceptions);
void Print(const v8::FunctionCallbackInfo<v8::Value>& args);
void Read(const v8::FunctionCallbackInfo<v8::Value>& args);
void Load(const v8::FunctionCallbackInfo<v8::Value>& args);
void Quit(const v8::FunctionCallbackInfo<v8::Value>& args);
void Version(const v8::FunctionCallbackInfo<v8::Value>& args);
void Alert(const v8::FunctionCallbackInfo<v8::Value>& args);
void Prompt(const v8::FunctionCallbackInfo<v8::Value>& args);
void Location(const v8::FunctionCallbackInfo<v8::Value>& args);
v8::MaybeLocal<v8::String> ReadFile(v8::Isolate* isolate, const char* name);
void ReportException(v8::Isolate* isolate, v8::TryCatch* handler);
static v8::Local<v8::ObjectTemplate> MakeLocationObjectTemplate(v8::Isolate* isolate);
static void XGetter(v8::Local<v8::String> property, const v8::PropertyCallbackInfo<v8::Value>& info);
 
static bool run_shell;
 
std::string href;
 
int main(int argc, char* argv[]) {
	v8::V8::InitializeICUDefaultLocation(argv[0]);
	v8::V8::InitializeExternalStartupData(argv[0]);
	v8::Platform* platform = v8::platform::CreateDefaultPlatform();
	v8::V8::InitializePlatform(platform);
	v8::V8::Initialize();
 
	v8::V8::SetFlagsFromCommandLine(&argc, argv, true);
	v8::Isolate::CreateParams create_params;
	create_params.array_buffer_allocator =
		v8::ArrayBuffer::Allocator::NewDefaultAllocator();
	v8::Isolate* isolate = v8::Isolate::New(create_params);
	//파라미터의 값이 없을때는 run_shell 가 true
	run_shell = (argc == 1);
	int result;
	{
		v8::Isolate::Scope isolate_scope(isolate);
		v8::HandleScope handle_scope(isolate);
		v8::Local<v8::Context> context = CreateShellContext(isolate);
 
 
		if (context.IsEmpty()) {
			fprintf(stderr, "Error creating context\n");
			return 1;
		}
		v8::Context::Scope context_scope(context);
		result = RunMain(isolate, platform, argc, argv);
		if (run_shell) RunShell(context, platform);
	}
	isolate->Dispose();
	v8::V8::Dispose();
	v8::V8::ShutdownPlatform();
	delete platform;
	delete create_params.array_buffer_allocator;
	return result;
}
 
 
// Extracts a C string from a V8 Utf8Value.
const char* ToCString(const v8::String::Utf8Value& value) {
	return *value ? *value : "<string conversion failed>";
}
 
v8::Local<v8::String> StringToV8String(std::string value)
{
	v8::Local<v8::String> ret = v8::String::NewFromUtf8(v8::Isolate::GetCurrent(), value.data());
	return ret;
}
 
std::string V8StringToString(v8::Local<v8::Value> value)
{
	v8::String::Utf8Value utf(value);
	return std::string(*utf);
}
 
//Aeccessing static Global variables
 
//Getter
void XGetter(v8::Local<v8::String> property, const v8::PropertyCallbackInfo<v8::Value>& info)
{	
	info.GetReturnValue().Set(StringToV8String(href));
}
//Setter
void XSetter(v8::Local<v8::String> property, v8::Local<v8::Value> value, const v8::PropertyCallbackInfo<v8::Value>& info)
{
	href = V8StringToString(value);
}
 
v8::Local<v8::ObjectTemplate> MakeLocationObjectTemplate(v8::Isolate* isolate)
{
	v8::EscapableHandleScope handle_scope(isolate);
 
	v8::Local<v8::ObjectTemplate> result = v8::ObjectTemplate::New(isolate);
	result->SetInternalFieldCount(1);
 
	result->SetAccessor(v8::String::NewFromUtf8(isolate, "href", v8::NewStringType::kInternalized).ToLocalChecked(), XGetter);
 
	return handle_scope.Escape(result);
}
 
// Creates a new execution environment containing the built-in
// functions.
v8::Local<v8::Context> CreateShellContext(v8::Isolate* isolate) {
	// Create a template for the global object.
	v8::Local<v8::ObjectTemplate> global = v8::ObjectTemplate::New(isolate);
 
	// Bind the global 'print' function to the C++ Print callback.
	global->Set(
		v8::String::NewFromUtf8(isolate, "print", v8::NewStringType::kNormal)
		.ToLocalChecked(),
		v8::FunctionTemplate::New(isolate, Print));
	// Bind the global 'read' function to the C++ Read callback.
	global->Set(v8::String::NewFromUtf8(
		isolate, "read", v8::NewStringType::kNormal).ToLocalChecked(),
		v8::FunctionTemplate::New(isolate, Read));
	// Bind the global 'load' function to the C++ Load callback.
	global->Set(v8::String::NewFromUtf8(
		isolate, "load", v8::NewStringType::kNormal).ToLocalChecked(),
		v8::FunctionTemplate::New(isolate, Load));
	// Bind the 'quit' function
	global->Set(v8::String::NewFromUtf8(
		isolate, "quit", v8::NewStringType::kNormal).ToLocalChecked(),
		v8::FunctionTemplate::New(isolate, Quit));
	// Bind the 'version' function
	global->Set(
		v8::String::NewFromUtf8(isolate, "version", v8::NewStringType::kNormal)
		.ToLocalChecked(),
		v8::FunctionTemplate::New(isolate, Version));
	// Bind the 'Alert' function
	global->Set(
		v8::String::NewFromUtf8(isolate, "alert", v8::NewStringType::kNormal)
		.ToLocalChecked(),
		v8::FunctionTemplate::New(isolate, Alert));
	// Bind the 'Prompt' function
	global->Set(
		v8::String::NewFromUtf8(isolate, "prompt", v8::NewStringType::kNormal)
		.ToLocalChecked(),
		v8::FunctionTemplate::New(isolate, Prompt));
	// Bind the 'location' function
	v8::Local<v8::ObjectTemplate> MLTempl = MakeLocationObjectTemplate(isolate);
	v8::Local<v8::Object> MLObject = MLTempl->NewInstance();
	global->Set(
		v8::String::NewFromUtf8(isolate, "location", v8::NewStringType::kInternalized)
		.ToLocalChecked(), MLObject);
 
	return v8::Context::New(isolate, NULL, global);
}
 
// The callback that is invoked by v8 whenever the JavaScript 'print'
// function is called.  Prints its arguments on stdout separated by
// spaces and ending with a newline.
void Print(const v8::FunctionCallbackInfo<v8::Value>& args) {
	bool first = true;
	for (int i = 0; i < args.Length(); i++) {
		v8::HandleScope handle_scope(args.GetIsolate());
		if (first) {
			first = false;
		}
		else {
			printf(" ");
		}
		v8::String::Utf8Value str(args[i]);
		const char* cstr = ToCString(str);
 
		printf("%s", cstr);
	}
	printf("\n");
	fflush(stdout);
}
 
 
// The callback that is invoked by v8 whenever the JavaScript 'read'
// function is called.  This function loads the content of the file named in
// the argument into a JavaScript string.
void Read(const v8::FunctionCallbackInfo<v8::Value>& args) {
	if (args.Length() != 1) {
		args.GetIsolate()->ThrowException(
			v8::String::NewFromUtf8(args.GetIsolate(), "Bad parameters",
				v8::NewStringType::kNormal).ToLocalChecked());
		return;
	}
	v8::String::Utf8Value file(args[0]);
	if (*file == NULL) {
		args.GetIsolate()->ThrowException(
			v8::String::NewFromUtf8(args.GetIsolate(), "Error loading file",
				v8::NewStringType::kNormal).ToLocalChecked());
		return;
	}
	v8::Local<v8::String> source;
	if (!ReadFile(args.GetIsolate(), *file).ToLocal(&source)) {
		args.GetIsolate()->ThrowException(
			v8::String::NewFromUtf8(args.GetIsolate(), "Error loading file",
				v8::NewStringType::kNormal).ToLocalChecked());
		return;
	}
	args.GetReturnValue().Set(source);
}
 
 
// The callback that is invoked by v8 whenever the JavaScript 'load'
// function is called.  Loads, compiles and executes its argument
// JavaScript file.
void Load(const v8::FunctionCallbackInfo<v8::Value>& args) {
	for (int i = 0; i < args.Length(); i++) {
		v8::HandleScope handle_scope(args.GetIsolate());
		v8::String::Utf8Value file(args[i]);
		if (*file == NULL) {
			args.GetIsolate()->ThrowException(
				v8::String::NewFromUtf8(args.GetIsolate(), "Error loading file",
					v8::NewStringType::kNormal).ToLocalChecked());
			return;
		}
		v8::Local<v8::String> source;
		if (!ReadFile(args.GetIsolate(), *file).ToLocal(&source)) {
			args.GetIsolate()->ThrowException(
				v8::String::NewFromUtf8(args.GetIsolate(), "Error loading file",
					v8::NewStringType::kNormal).ToLocalChecked());
			return;
		}
		if (!ExecuteString(args.GetIsolate(), source, args[i], false, false)) {
			args.GetIsolate()->ThrowException(
				v8::String::NewFromUtf8(args.GetIsolate(), "Error executing file",
					v8::NewStringType::kNormal).ToLocalChecked());
			return;
		}
	}
}
 
 
// The callback that is invoked by v8 whenever the JavaScript 'quit'
// function is called.  Quits.
void Quit(const v8::FunctionCallbackInfo<v8::Value>& args) {
	// If not arguments are given args[0] will yield undefined which
	// converts to the integer value 0.
	int exit_code =
		args[0]->Int32Value(args.GetIsolate()->GetCurrentContext()).FromMaybe(0);
	fflush(stdout);
	fflush(stderr);
	exit(exit_code);
}
 
 
void Version(const v8::FunctionCallbackInfo<v8::Value>& args) {
	args.GetReturnValue().Set(
		v8::String::NewFromUtf8(args.GetIsolate(), v8::V8::GetVersion(),
			v8::NewStringType::kNormal).ToLocalChecked());
}
 
// Alert 함수 정의
void Alert(const v8::FunctionCallbackInfo<v8::Value>& args)
{
	v8::String::Utf8Value context(args[0]);
 
	const char* cstrc = ToCString(context);
 
	printf("alert : %s", cstrc);
	printf("\n");
	return;
}
 
void Prompt(const v8::FunctionCallbackInfo<v8::Value>& args)
{
	v8::String::Utf8Value Message(args[0]);
	v8::String::Utf8Value DefaultValue(args[1]);
 
	const char* cstrm = ToCString(Message);
	const char* cstrdv = ToCString(DefaultValue);
 
	printf("promrt message : %s", cstrm);
	printf("\nprompt default value : %s", cstrdv);
	printf("\n");
	return;
}
 
// Location함수 정의
void Location(const v8::FunctionCallbackInfo<v8::Value>& args)
{
	v8::String::Utf8Value url(args[0]);
 
	const char* cstru = ToCString(url);
 
	printf("location URL : %s", cstru);
	printf("\n");
	return;
}
 
// Reads a file into a v8 string.
v8::MaybeLocal<v8::String> ReadFile(v8::Isolate* isolate, const char* name) {
	FILE* file;
	fopen_s(&file, name, "rb");
	if (file == NULL) return v8::MaybeLocal<v8::String>();
 
	fseek(file, 0, SEEK_END);
	size_t size = ftell(file);
	rewind(file);
 
	char* chars = new char[size + 1];
	chars[size] = '\0';
	for (size_t i = 0; i < size;) {
		i += fread(&chars[i], 1, size - i, file);
		if (ferror(file)) {
			fclose(file);
			return v8::MaybeLocal<v8::String>();
		}
	}
	fclose(file);
	v8::MaybeLocal<v8::String> result = v8::String::NewFromUtf8(
		isolate, chars, v8::NewStringType::kNormal, static_cast<int>(size));
	delete[] chars;
	return result;
}
 
 
// Process remaining command line arguments and execute files
int RunMain(v8::Isolate* isolate, v8::Platform* platform, int argc,
	char* argv[]) {
 
	//파라미터 개수에 따라 loop
	for (int i = 1; i < argc; i++) {
		const char* str = argv[i];
 
		if (strcmp(str, "--shell") == 0) {
			run_shell = true;
		}
		else if (strcmp(str, "-f") == 0) {
			// Ignore any -f flags for compatibility with the other stand-
			// alone JavaScript engines.
			continue;
		}
		else if (strncmp(str, "--", 2) == 0) {
			fprintf(stderr,
				"Warning: unknown flag %s.\nTry --help for options\n", str);
		}
		else if (strcmp(str, "-e") == 0 && i + 1 < argc) {
			// Execute argument given to -e option directly.
			v8::Local<v8::String> file_name =
				v8::String::NewFromUtf8(isolate, "unnamed",
					v8::NewStringType::kNormal).ToLocalChecked();
			v8::Local<v8::String> source;
			if (!v8::String::NewFromUtf8(isolate, argv[++i],
				v8::NewStringType::kNormal)
				.ToLocal(&source)) {
				return 1;
			}
			bool success = ExecuteString(isolate, source, file_name, false, true);
			while (v8::platform::PumpMessageLoop(platform, isolate)) continue;
			if (!success) return 1;
		}
		else {
			// Use all other arguments as names of files to load and run.
			v8::Local<v8::String> file_name =
				v8::String::NewFromUtf8(isolate, str, v8::NewStringType::kNormal)
				.ToLocalChecked();
			v8::Local<v8::String> source;
			if (!ReadFile(isolate, str).ToLocal(&source)) {
				fprintf(stderr, "Error reading '%s'\n", str);
				continue;
			}
			bool success = ExecuteString(isolate, source, file_name, false, true);
			while (v8::platform::PumpMessageLoop(platform, isolate)) continue;
			if (!success) return 1;
		}
	}
	return 0;
}
 
 
// The read-eval-execute loop of the shell.
void RunShell(v8::Local<v8::Context> context, v8::Platform* platform) {
	fprintf(stderr, "V8 version %s [sample shell]\n", v8::V8::GetVersion());
	static const int kBufferSize = 256;
	// Enter the execution environment before evaluating any code.
	v8::Context::Scope context_scope(context);
	v8::Local<v8::String> name(
		v8::String::NewFromUtf8(context->GetIsolate(), "(shell)",
			v8::NewStringType::kNormal).ToLocalChecked());
	while (true) {
		char buffer[kBufferSize];
		fprintf(stderr, "> ");
		char* str = fgets(buffer, kBufferSize, stdin);
		if (str == NULL) break;
		v8::HandleScope handle_scope(context->GetIsolate());
		ExecuteString(
			context->GetIsolate(),
			v8::String::NewFromUtf8(context->GetIsolate(), str,
				v8::NewStringType::kNormal).ToLocalChecked(),
			name, true, true);
		while (v8::platform::PumpMessageLoop(platform, context->GetIsolate()))
			continue;
	}
	fprintf(stderr, "\n");
}
 
// Executes a string within the current v8 context.
bool ExecuteString(v8::Isolate* isolate, v8::Local<v8::String> source,
	v8::Local<v8::Value> name, bool print_result,
	bool report_exceptions) {
	v8::HandleScope handle_scope(isolate);
	v8::TryCatch try_catch(isolate);
	v8::ScriptOrigin origin(name);
	v8::Local<v8::Context> context(isolate->GetCurrentContext());
	v8::Local<v8::Script> script;
	if (!v8::Script::Compile(context, source, &origin).ToLocal(&script)) {
		// Print errors that happened during compilation.
		if (report_exceptions)
			ReportException(isolate, &try_catch);
		return false;
	}
	else {
		v8::Local<v8::Value> result;
		if (!script->Run(context).ToLocal(&result)) {
			assert(try_catch.HasCaught());
			// Print errors that happened during execution.
			if (report_exceptions)
				ReportException(isolate, &try_catch);
			return false;
		}
		else {
			assert(!try_catch.HasCaught());
			if (print_result && !result->IsUndefined()) {
				// If all went well and the result wasn't undefined then print
				// the returned value.
				v8::String::Utf8Value str(result);
				const char* cstr = ToCString(str);
				printf("%s\n", cstr);
			}
			return true;
		}
	}
}
 
 
void ReportException(v8::Isolate* isolate, v8::TryCatch* try_catch) {
	v8::HandleScope handle_scope(isolate);
	v8::String::Utf8Value exception(try_catch->Exception());
	const char* exception_string = ToCString(exception);
	v8::Local<v8::Message> message = try_catch->Message();
	if (message.IsEmpty()) {
		// V8 didn't provide any extra information about this error; just
		// print the exception.
		fprintf(stderr, "%s\n", exception_string);
	}
	else {
		// Print (filename):(line number): (message).
		v8::String::Utf8Value filename(message->GetScriptOrigin().ResourceName());
		v8::Local<v8::Context> context(isolate->GetCurrentContext());
		const char* filename_string = ToCString(filename);
		int linenum = message->GetLineNumber(context).FromJust();
		fprintf(stderr, "%s:%i: %s\n", filename_string, linenum, exception_string);
		// Print line of source code.
		v8::String::Utf8Value sourceline(
			message->GetSourceLine(context).ToLocalChecked());
		const char* sourceline_string = ToCString(sourceline);
		fprintf(stderr, "%s\n", sourceline_string);
		// Print wavy underline (GetUnderline is deprecated).
		int start = message->GetStartColumn(context).FromJust();
		for (int i = 0; i < start; i++) {
			fprintf(stderr, " ");
		}
		int end = message->GetEndColumn(context).FromJust();
		for (int i = start; i < end; i++) {
			fprintf(stderr, "^");
		}
		fprintf(stderr, "\n");
		v8::Local<v8::Value> stack_trace_string;
		if (try_catch->StackTrace(context).ToLocal(&stack_trace_string) &&
			stack_trace_string->IsString() &&
			v8::Local<v8::String>::Cast(stack_trace_string)->Length() > 0) {
			v8::String::Utf8Value stack_trace(stack_trace_string);
			const char* stack_trace_string = ToCString(stack_trace);
			fprintf(stderr, "%s\n", stack_trace_string);
		}
	}
}