1 // Copyright 2012 the V8 project authors. All rights reserved.
2 // Redistribution and use in source and binary forms, with or without
3 // modification, are permitted provided that the following conditions are
6 // * Redistributions of source code must retain the above copyright
7 // notice, this list of conditions and the following disclaimer.
8 // * Redistributions in binary form must reproduce the above
9 // copyright notice, this list of conditions and the following
10 // disclaimer in the documentation and/or other materials provided
11 // with the distribution.
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13 // contributors may be used to endorse or promote products derived
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16 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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28 #include <include/v8.h>
30 #include <include/libplatform/libplatform.h>
38 #ifdef COMPRESS_STARTUP_DATA_BZ2
39 #error Using compressed startup data is not supported for this sample
43 * This sample program shows how to implement a simple javascript shell
44 * based on V8. This includes initializing V8 with command line options,
45 * creating global functions, compiling and executing strings.
47 * For a more sophisticated shell, consider using the debug shell D8.
51 v8::Handle<v8::Context> CreateShellContext(v8::Isolate* isolate);
52 void RunShell(v8::Handle<v8::Context> context);
53 int RunMain(v8::Isolate* isolate, int argc, char* argv[]);
54 bool ExecuteString(v8::Isolate* isolate,
55 v8::Handle<v8::String> source,
56 v8::Handle<v8::Value> name,
58 bool report_exceptions);
59 void Print(const v8::FunctionCallbackInfo<v8::Value>& args);
60 void Read(const v8::FunctionCallbackInfo<v8::Value>& args);
61 void Load(const v8::FunctionCallbackInfo<v8::Value>& args);
62 void Quit(const v8::FunctionCallbackInfo<v8::Value>& args);
63 void Version(const v8::FunctionCallbackInfo<v8::Value>& args);
64 v8::Handle<v8::String> ReadFile(v8::Isolate* isolate, const char* name);
65 void ReportException(v8::Isolate* isolate, v8::TryCatch* handler);
68 static bool run_shell;
71 class ShellArrayBufferAllocator : public v8::ArrayBuffer::Allocator {
73 virtual void* Allocate(size_t length) {
74 void* data = AllocateUninitialized(length);
75 return data == NULL ? data : memset(data, 0, length);
77 virtual void* AllocateUninitialized(size_t length) { return malloc(length); }
78 virtual void Free(void* data, size_t) { free(data); }
82 int main(int argc, char* argv[]) {
83 v8::V8::InitializeICU();
84 v8::Platform* platform = v8::platform::CreateDefaultPlatform();
85 v8::V8::InitializePlatform(platform);
86 v8::V8::SetFlagsFromCommandLine(&argc, argv, true);
87 ShellArrayBufferAllocator array_buffer_allocator;
88 v8::V8::SetArrayBufferAllocator(&array_buffer_allocator);
89 v8::Isolate* isolate = v8::Isolate::New();
90 run_shell = (argc == 1);
93 v8::Isolate::Scope isolate_scope(isolate);
94 v8::HandleScope handle_scope(isolate);
95 v8::Handle<v8::Context> context = CreateShellContext(isolate);
96 if (context.IsEmpty()) {
97 fprintf(stderr, "Error creating context\n");
100 v8::Context::Scope context_scope(context);
101 result = RunMain(isolate, argc, argv);
102 if (run_shell) RunShell(context);
105 v8::V8::ShutdownPlatform();
111 // Extracts a C string from a V8 Utf8Value.
112 const char* ToCString(const v8::String::Utf8Value& value) {
113 return *value ? *value : "<string conversion failed>";
117 // Creates a new execution environment containing the built-in
119 v8::Handle<v8::Context> CreateShellContext(v8::Isolate* isolate) {
120 // Create a template for the global object.
121 v8::Handle<v8::ObjectTemplate> global = v8::ObjectTemplate::New(isolate);
122 // Bind the global 'print' function to the C++ Print callback.
123 global->Set(v8::String::NewFromUtf8(isolate, "print"),
124 v8::FunctionTemplate::New(isolate, Print));
125 // Bind the global 'read' function to the C++ Read callback.
126 global->Set(v8::String::NewFromUtf8(isolate, "read"),
127 v8::FunctionTemplate::New(isolate, Read));
128 // Bind the global 'load' function to the C++ Load callback.
129 global->Set(v8::String::NewFromUtf8(isolate, "load"),
130 v8::FunctionTemplate::New(isolate, Load));
131 // Bind the 'quit' function
132 global->Set(v8::String::NewFromUtf8(isolate, "quit"),
133 v8::FunctionTemplate::New(isolate, Quit));
134 // Bind the 'version' function
135 global->Set(v8::String::NewFromUtf8(isolate, "version"),
136 v8::FunctionTemplate::New(isolate, Version));
138 return v8::Context::New(isolate, NULL, global);
142 // The callback that is invoked by v8 whenever the JavaScript 'print'
143 // function is called. Prints its arguments on stdout separated by
144 // spaces and ending with a newline.
145 void Print(const v8::FunctionCallbackInfo<v8::Value>& args) {
147 for (int i = 0; i < args.Length(); i++) {
148 v8::HandleScope handle_scope(args.GetIsolate());
154 v8::String::Utf8Value str(args[i]);
155 const char* cstr = ToCString(str);
163 // The callback that is invoked by v8 whenever the JavaScript 'read'
164 // function is called. This function loads the content of the file named in
165 // the argument into a JavaScript string.
166 void Read(const v8::FunctionCallbackInfo<v8::Value>& args) {
167 if (args.Length() != 1) {
168 args.GetIsolate()->ThrowException(
169 v8::String::NewFromUtf8(args.GetIsolate(), "Bad parameters"));
172 v8::String::Utf8Value file(args[0]);
174 args.GetIsolate()->ThrowException(
175 v8::String::NewFromUtf8(args.GetIsolate(), "Error loading file"));
178 v8::Handle<v8::String> source = ReadFile(args.GetIsolate(), *file);
179 if (source.IsEmpty()) {
180 args.GetIsolate()->ThrowException(
181 v8::String::NewFromUtf8(args.GetIsolate(), "Error loading file"));
184 args.GetReturnValue().Set(source);
188 // The callback that is invoked by v8 whenever the JavaScript 'load'
189 // function is called. Loads, compiles and executes its argument
191 void Load(const v8::FunctionCallbackInfo<v8::Value>& args) {
192 for (int i = 0; i < args.Length(); i++) {
193 v8::HandleScope handle_scope(args.GetIsolate());
194 v8::String::Utf8Value file(args[i]);
196 args.GetIsolate()->ThrowException(
197 v8::String::NewFromUtf8(args.GetIsolate(), "Error loading file"));
200 v8::Handle<v8::String> source = ReadFile(args.GetIsolate(), *file);
201 if (source.IsEmpty()) {
202 args.GetIsolate()->ThrowException(
203 v8::String::NewFromUtf8(args.GetIsolate(), "Error loading file"));
206 if (!ExecuteString(args.GetIsolate(),
208 v8::String::NewFromUtf8(args.GetIsolate(), *file),
211 args.GetIsolate()->ThrowException(
212 v8::String::NewFromUtf8(args.GetIsolate(), "Error executing file"));
219 // The callback that is invoked by v8 whenever the JavaScript 'quit'
220 // function is called. Quits.
221 void Quit(const v8::FunctionCallbackInfo<v8::Value>& args) {
222 // If not arguments are given args[0] will yield undefined which
223 // converts to the integer value 0.
224 int exit_code = args[0]->Int32Value();
231 void Version(const v8::FunctionCallbackInfo<v8::Value>& args) {
232 args.GetReturnValue().Set(
233 v8::String::NewFromUtf8(args.GetIsolate(), v8::V8::GetVersion()));
237 // Reads a file into a v8 string.
238 v8::Handle<v8::String> ReadFile(v8::Isolate* isolate, const char* name) {
239 FILE* file = fopen(name, "rb");
240 if (file == NULL) return v8::Handle<v8::String>();
242 fseek(file, 0, SEEK_END);
243 int size = ftell(file);
246 char* chars = new char[size + 1];
248 for (int i = 0; i < size;) {
249 int read = static_cast<int>(fread(&chars[i], 1, size - i, file));
253 v8::Handle<v8::String> result =
254 v8::String::NewFromUtf8(isolate, chars, v8::String::kNormalString, size);
260 // Process remaining command line arguments and execute files
261 int RunMain(v8::Isolate* isolate, int argc, char* argv[]) {
262 for (int i = 1; i < argc; i++) {
263 const char* str = argv[i];
264 if (strcmp(str, "--shell") == 0) {
266 } else if (strcmp(str, "-f") == 0) {
267 // Ignore any -f flags for compatibility with the other stand-
268 // alone JavaScript engines.
270 } else if (strncmp(str, "--", 2) == 0) {
272 "Warning: unknown flag %s.\nTry --help for options\n", str);
273 } else if (strcmp(str, "-e") == 0 && i + 1 < argc) {
274 // Execute argument given to -e option directly.
275 v8::Handle<v8::String> file_name =
276 v8::String::NewFromUtf8(isolate, "unnamed");
277 v8::Handle<v8::String> source =
278 v8::String::NewFromUtf8(isolate, argv[++i]);
279 if (!ExecuteString(isolate, source, file_name, false, true)) return 1;
281 // Use all other arguments as names of files to load and run.
282 v8::Handle<v8::String> file_name = v8::String::NewFromUtf8(isolate, str);
283 v8::Handle<v8::String> source = ReadFile(isolate, str);
284 if (source.IsEmpty()) {
285 fprintf(stderr, "Error reading '%s'\n", str);
288 if (!ExecuteString(isolate, source, file_name, false, true)) return 1;
295 // The read-eval-execute loop of the shell.
296 void RunShell(v8::Handle<v8::Context> context) {
297 fprintf(stderr, "V8 version %s [sample shell]\n", v8::V8::GetVersion());
298 static const int kBufferSize = 256;
299 // Enter the execution environment before evaluating any code.
300 v8::Context::Scope context_scope(context);
301 v8::Local<v8::String> name(
302 v8::String::NewFromUtf8(context->GetIsolate(), "(shell)"));
304 char buffer[kBufferSize];
305 fprintf(stderr, "> ");
306 char* str = fgets(buffer, kBufferSize, stdin);
307 if (str == NULL) break;
308 v8::HandleScope handle_scope(context->GetIsolate());
309 ExecuteString(context->GetIsolate(),
310 v8::String::NewFromUtf8(context->GetIsolate(), str),
315 fprintf(stderr, "\n");
319 // Executes a string within the current v8 context.
320 bool ExecuteString(v8::Isolate* isolate,
321 v8::Handle<v8::String> source,
322 v8::Handle<v8::Value> name,
324 bool report_exceptions) {
325 v8::HandleScope handle_scope(isolate);
326 v8::TryCatch try_catch;
327 v8::ScriptOrigin origin(name);
328 v8::Handle<v8::Script> script = v8::Script::Compile(source, &origin);
329 if (script.IsEmpty()) {
330 // Print errors that happened during compilation.
331 if (report_exceptions)
332 ReportException(isolate, &try_catch);
335 v8::Handle<v8::Value> result = script->Run();
336 if (result.IsEmpty()) {
337 assert(try_catch.HasCaught());
338 // Print errors that happened during execution.
339 if (report_exceptions)
340 ReportException(isolate, &try_catch);
343 assert(!try_catch.HasCaught());
344 if (print_result && !result->IsUndefined()) {
345 // If all went well and the result wasn't undefined then print
346 // the returned value.
347 v8::String::Utf8Value str(result);
348 const char* cstr = ToCString(str);
349 printf("%s\n", cstr);
357 void ReportException(v8::Isolate* isolate, v8::TryCatch* try_catch) {
358 v8::HandleScope handle_scope(isolate);
359 v8::String::Utf8Value exception(try_catch->Exception());
360 const char* exception_string = ToCString(exception);
361 v8::Handle<v8::Message> message = try_catch->Message();
362 if (message.IsEmpty()) {
363 // V8 didn't provide any extra information about this error; just
364 // print the exception.
365 fprintf(stderr, "%s\n", exception_string);
367 // Print (filename):(line number): (message).
368 v8::String::Utf8Value filename(message->GetScriptOrigin().ResourceName());
369 const char* filename_string = ToCString(filename);
370 int linenum = message->GetLineNumber();
371 fprintf(stderr, "%s:%i: %s\n", filename_string, linenum, exception_string);
372 // Print line of source code.
373 v8::String::Utf8Value sourceline(message->GetSourceLine());
374 const char* sourceline_string = ToCString(sourceline);
375 fprintf(stderr, "%s\n", sourceline_string);
376 // Print wavy underline (GetUnderline is deprecated).
377 int start = message->GetStartColumn();
378 for (int i = 0; i < start; i++) {
379 fprintf(stderr, " ");
381 int end = message->GetEndColumn();
382 for (int i = start; i < end; i++) {
383 fprintf(stderr, "^");
385 fprintf(stderr, "\n");
386 v8::String::Utf8Value stack_trace(try_catch->StackTrace());
387 if (stack_trace.length() > 0) {
388 const char* stack_trace_string = ToCString(stack_trace);
389 fprintf(stderr, "%s\n", stack_trace_string);