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
4// met:
5//
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.
12//     * Neither the name of Google Inc. nor the names of its
13//       contributors may be used to endorse or promote products derived
14//       from this software without specific prior written permission.
15//
16// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
17// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
18// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
19// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
20// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
21// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
22// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
26// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27
28#include <include/v8.h>
29
30#include <include/libplatform/libplatform.h>
31
32#include <assert.h>
33#include <fcntl.h>
34#include <stdio.h>
35#include <stdlib.h>
36#include <string.h>
37
38#ifdef COMPRESS_STARTUP_DATA_BZ2
39#error Using compressed startup data is not supported for this sample
40#endif
41
42/**
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.
46 *
47 * For a more sophisticated shell, consider using the debug shell D8.
48 */
49
50
51v8::Handle<v8::Context> CreateShellContext(v8::Isolate* isolate);
52void RunShell(v8::Handle<v8::Context> context);
53int RunMain(v8::Isolate* isolate, int argc, char* argv[]);
54bool ExecuteString(v8::Isolate* isolate,
55                   v8::Handle<v8::String> source,
56                   v8::Handle<v8::Value> name,
57                   bool print_result,
58                   bool report_exceptions);
59void Print(const v8::FunctionCallbackInfo<v8::Value>& args);
60void Read(const v8::FunctionCallbackInfo<v8::Value>& args);
61void Load(const v8::FunctionCallbackInfo<v8::Value>& args);
62void Quit(const v8::FunctionCallbackInfo<v8::Value>& args);
63void Version(const v8::FunctionCallbackInfo<v8::Value>& args);
64v8::Handle<v8::String> ReadFile(v8::Isolate* isolate, const char* name);
65void ReportException(v8::Isolate* isolate, v8::TryCatch* handler);
66
67
68static bool run_shell;
69
70
71class ShellArrayBufferAllocator : public v8::ArrayBuffer::Allocator {
72 public:
73  virtual void* Allocate(size_t length) {
74    void* data = AllocateUninitialized(length);
75    return data == NULL ? data : memset(data, 0, length);
76  }
77  virtual void* AllocateUninitialized(size_t length) { return malloc(length); }
78  virtual void Free(void* data, size_t) { free(data); }
79};
80
81
82int main(int argc, char* argv[]) {
83  v8::V8::InitializeICU();
84  v8::Platform* platform = v8::platform::CreateDefaultPlatform();
85  v8::V8::InitializePlatform(platform);
86  v8::V8::Initialize();
87  v8::V8::SetFlagsFromCommandLine(&argc, argv, true);
88  ShellArrayBufferAllocator array_buffer_allocator;
89  v8::V8::SetArrayBufferAllocator(&array_buffer_allocator);
90  v8::Isolate* isolate = v8::Isolate::New();
91  run_shell = (argc == 1);
92  int result;
93  {
94    v8::Isolate::Scope isolate_scope(isolate);
95    v8::HandleScope handle_scope(isolate);
96    v8::Handle<v8::Context> context = CreateShellContext(isolate);
97    if (context.IsEmpty()) {
98      fprintf(stderr, "Error creating context\n");
99      return 1;
100    }
101    v8::Context::Scope context_scope(context);
102    result = RunMain(isolate, argc, argv);
103    if (run_shell) RunShell(context);
104  }
105  v8::V8::Dispose();
106  v8::V8::ShutdownPlatform();
107  delete platform;
108  return result;
109}
110
111
112// Extracts a C string from a V8 Utf8Value.
113const char* ToCString(const v8::String::Utf8Value& value) {
114  return *value ? *value : "<string conversion failed>";
115}
116
117
118// Creates a new execution environment containing the built-in
119// functions.
120v8::Handle<v8::Context> CreateShellContext(v8::Isolate* isolate) {
121  // Create a template for the global object.
122  v8::Handle<v8::ObjectTemplate> global = v8::ObjectTemplate::New(isolate);
123  // Bind the global 'print' function to the C++ Print callback.
124  global->Set(v8::String::NewFromUtf8(isolate, "print"),
125              v8::FunctionTemplate::New(isolate, Print));
126  // Bind the global 'read' function to the C++ Read callback.
127  global->Set(v8::String::NewFromUtf8(isolate, "read"),
128              v8::FunctionTemplate::New(isolate, Read));
129  // Bind the global 'load' function to the C++ Load callback.
130  global->Set(v8::String::NewFromUtf8(isolate, "load"),
131              v8::FunctionTemplate::New(isolate, Load));
132  // Bind the 'quit' function
133  global->Set(v8::String::NewFromUtf8(isolate, "quit"),
134              v8::FunctionTemplate::New(isolate, Quit));
135  // Bind the 'version' function
136  global->Set(v8::String::NewFromUtf8(isolate, "version"),
137              v8::FunctionTemplate::New(isolate, Version));
138
139  return v8::Context::New(isolate, NULL, global);
140}
141
142
143// The callback that is invoked by v8 whenever the JavaScript 'print'
144// function is called.  Prints its arguments on stdout separated by
145// spaces and ending with a newline.
146void Print(const v8::FunctionCallbackInfo<v8::Value>& args) {
147  bool first = true;
148  for (int i = 0; i < args.Length(); i++) {
149    v8::HandleScope handle_scope(args.GetIsolate());
150    if (first) {
151      first = false;
152    } else {
153      printf(" ");
154    }
155    v8::String::Utf8Value str(args[i]);
156    const char* cstr = ToCString(str);
157    printf("%s", cstr);
158  }
159  printf("\n");
160  fflush(stdout);
161}
162
163
164// The callback that is invoked by v8 whenever the JavaScript 'read'
165// function is called.  This function loads the content of the file named in
166// the argument into a JavaScript string.
167void Read(const v8::FunctionCallbackInfo<v8::Value>& args) {
168  if (args.Length() != 1) {
169    args.GetIsolate()->ThrowException(
170        v8::String::NewFromUtf8(args.GetIsolate(), "Bad parameters"));
171    return;
172  }
173  v8::String::Utf8Value file(args[0]);
174  if (*file == NULL) {
175    args.GetIsolate()->ThrowException(
176        v8::String::NewFromUtf8(args.GetIsolate(), "Error loading file"));
177    return;
178  }
179  v8::Handle<v8::String> source = ReadFile(args.GetIsolate(), *file);
180  if (source.IsEmpty()) {
181    args.GetIsolate()->ThrowException(
182        v8::String::NewFromUtf8(args.GetIsolate(), "Error loading file"));
183    return;
184  }
185  args.GetReturnValue().Set(source);
186}
187
188
189// The callback that is invoked by v8 whenever the JavaScript 'load'
190// function is called.  Loads, compiles and executes its argument
191// JavaScript file.
192void Load(const v8::FunctionCallbackInfo<v8::Value>& args) {
193  for (int i = 0; i < args.Length(); i++) {
194    v8::HandleScope handle_scope(args.GetIsolate());
195    v8::String::Utf8Value file(args[i]);
196    if (*file == NULL) {
197      args.GetIsolate()->ThrowException(
198          v8::String::NewFromUtf8(args.GetIsolate(), "Error loading file"));
199      return;
200    }
201    v8::Handle<v8::String> source = ReadFile(args.GetIsolate(), *file);
202    if (source.IsEmpty()) {
203      args.GetIsolate()->ThrowException(
204           v8::String::NewFromUtf8(args.GetIsolate(), "Error loading file"));
205      return;
206    }
207    if (!ExecuteString(args.GetIsolate(),
208                       source,
209                       v8::String::NewFromUtf8(args.GetIsolate(), *file),
210                       false,
211                       false)) {
212      args.GetIsolate()->ThrowException(
213          v8::String::NewFromUtf8(args.GetIsolate(), "Error executing file"));
214      return;
215    }
216  }
217}
218
219
220// The callback that is invoked by v8 whenever the JavaScript 'quit'
221// function is called.  Quits.
222void Quit(const v8::FunctionCallbackInfo<v8::Value>& args) {
223  // If not arguments are given args[0] will yield undefined which
224  // converts to the integer value 0.
225  int exit_code = args[0]->Int32Value();
226  fflush(stdout);
227  fflush(stderr);
228  exit(exit_code);
229}
230
231
232void Version(const v8::FunctionCallbackInfo<v8::Value>& args) {
233  args.GetReturnValue().Set(
234      v8::String::NewFromUtf8(args.GetIsolate(), v8::V8::GetVersion()));
235}
236
237
238// Reads a file into a v8 string.
239v8::Handle<v8::String> ReadFile(v8::Isolate* isolate, const char* name) {
240  FILE* file = fopen(name, "rb");
241  if (file == NULL) return v8::Handle<v8::String>();
242
243  fseek(file, 0, SEEK_END);
244  int size = ftell(file);
245  rewind(file);
246
247  char* chars = new char[size + 1];
248  chars[size] = '\0';
249  for (int i = 0; i < size;) {
250    int read = static_cast<int>(fread(&chars[i], 1, size - i, file));
251    i += read;
252  }
253  fclose(file);
254  v8::Handle<v8::String> result =
255      v8::String::NewFromUtf8(isolate, chars, v8::String::kNormalString, size);
256  delete[] chars;
257  return result;
258}
259
260
261// Process remaining command line arguments and execute files
262int RunMain(v8::Isolate* isolate, int argc, char* argv[]) {
263  for (int i = 1; i < argc; i++) {
264    const char* str = argv[i];
265    if (strcmp(str, "--shell") == 0) {
266      run_shell = true;
267    } else if (strcmp(str, "-f") == 0) {
268      // Ignore any -f flags for compatibility with the other stand-
269      // alone JavaScript engines.
270      continue;
271    } else if (strncmp(str, "--", 2) == 0) {
272      fprintf(stderr,
273              "Warning: unknown flag %s.\nTry --help for options\n", str);
274    } else if (strcmp(str, "-e") == 0 && i + 1 < argc) {
275      // Execute argument given to -e option directly.
276      v8::Handle<v8::String> file_name =
277          v8::String::NewFromUtf8(isolate, "unnamed");
278      v8::Handle<v8::String> source =
279          v8::String::NewFromUtf8(isolate, argv[++i]);
280      if (!ExecuteString(isolate, source, file_name, false, true)) return 1;
281    } else {
282      // Use all other arguments as names of files to load and run.
283      v8::Handle<v8::String> file_name = v8::String::NewFromUtf8(isolate, str);
284      v8::Handle<v8::String> source = ReadFile(isolate, str);
285      if (source.IsEmpty()) {
286        fprintf(stderr, "Error reading '%s'\n", str);
287        continue;
288      }
289      if (!ExecuteString(isolate, source, file_name, false, true)) return 1;
290    }
291  }
292  return 0;
293}
294
295
296// The read-eval-execute loop of the shell.
297void RunShell(v8::Handle<v8::Context> context) {
298  fprintf(stderr, "V8 version %s [sample shell]\n", v8::V8::GetVersion());
299  static const int kBufferSize = 256;
300  // Enter the execution environment before evaluating any code.
301  v8::Context::Scope context_scope(context);
302  v8::Local<v8::String> name(
303      v8::String::NewFromUtf8(context->GetIsolate(), "(shell)"));
304  while (true) {
305    char buffer[kBufferSize];
306    fprintf(stderr, "> ");
307    char* str = fgets(buffer, kBufferSize, stdin);
308    if (str == NULL) break;
309    v8::HandleScope handle_scope(context->GetIsolate());
310    ExecuteString(context->GetIsolate(),
311                  v8::String::NewFromUtf8(context->GetIsolate(), str),
312                  name,
313                  true,
314                  true);
315  }
316  fprintf(stderr, "\n");
317}
318
319
320// Executes a string within the current v8 context.
321bool ExecuteString(v8::Isolate* isolate,
322                   v8::Handle<v8::String> source,
323                   v8::Handle<v8::Value> name,
324                   bool print_result,
325                   bool report_exceptions) {
326  v8::HandleScope handle_scope(isolate);
327  v8::TryCatch try_catch;
328  v8::ScriptOrigin origin(name);
329  v8::Handle<v8::Script> script = v8::Script::Compile(source, &origin);
330  if (script.IsEmpty()) {
331    // Print errors that happened during compilation.
332    if (report_exceptions)
333      ReportException(isolate, &try_catch);
334    return false;
335  } else {
336    v8::Handle<v8::Value> result = script->Run();
337    if (result.IsEmpty()) {
338      assert(try_catch.HasCaught());
339      // Print errors that happened during execution.
340      if (report_exceptions)
341        ReportException(isolate, &try_catch);
342      return false;
343    } else {
344      assert(!try_catch.HasCaught());
345      if (print_result && !result->IsUndefined()) {
346        // If all went well and the result wasn't undefined then print
347        // the returned value.
348        v8::String::Utf8Value str(result);
349        const char* cstr = ToCString(str);
350        printf("%s\n", cstr);
351      }
352      return true;
353    }
354  }
355}
356
357
358void ReportException(v8::Isolate* isolate, v8::TryCatch* try_catch) {
359  v8::HandleScope handle_scope(isolate);
360  v8::String::Utf8Value exception(try_catch->Exception());
361  const char* exception_string = ToCString(exception);
362  v8::Handle<v8::Message> message = try_catch->Message();
363  if (message.IsEmpty()) {
364    // V8 didn't provide any extra information about this error; just
365    // print the exception.
366    fprintf(stderr, "%s\n", exception_string);
367  } else {
368    // Print (filename):(line number): (message).
369    v8::String::Utf8Value filename(message->GetScriptOrigin().ResourceName());
370    const char* filename_string = ToCString(filename);
371    int linenum = message->GetLineNumber();
372    fprintf(stderr, "%s:%i: %s\n", filename_string, linenum, exception_string);
373    // Print line of source code.
374    v8::String::Utf8Value sourceline(message->GetSourceLine());
375    const char* sourceline_string = ToCString(sourceline);
376    fprintf(stderr, "%s\n", sourceline_string);
377    // Print wavy underline (GetUnderline is deprecated).
378    int start = message->GetStartColumn();
379    for (int i = 0; i < start; i++) {
380      fprintf(stderr, " ");
381    }
382    int end = message->GetEndColumn();
383    for (int i = start; i < end; i++) {
384      fprintf(stderr, "^");
385    }
386    fprintf(stderr, "\n");
387    v8::String::Utf8Value stack_trace(try_catch->StackTrace());
388    if (stack_trace.length() > 0) {
389      const char* stack_trace_string = ToCString(stack_trace);
390      fprintf(stderr, "%s\n", stack_trace_string);
391    }
392  }
393}
394