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/**
39 * This sample program shows how to implement a simple javascript shell
40 * based on V8.  This includes initializing V8 with command line options,
41 * creating global functions, compiling and executing strings.
42 *
43 * For a more sophisticated shell, consider using the debug shell D8.
44 */
45
46
47v8::Local<v8::Context> CreateShellContext(v8::Isolate* isolate);
48void RunShell(v8::Local<v8::Context> context, v8::Platform* platform);
49int RunMain(v8::Isolate* isolate, v8::Platform* platform, int argc,
50            char* argv[]);
51bool ExecuteString(v8::Isolate* isolate, v8::Local<v8::String> source,
52                   v8::Local<v8::Value> name, bool print_result,
53                   bool report_exceptions);
54void Print(const v8::FunctionCallbackInfo<v8::Value>& args);
55void Read(const v8::FunctionCallbackInfo<v8::Value>& args);
56void Load(const v8::FunctionCallbackInfo<v8::Value>& args);
57void Quit(const v8::FunctionCallbackInfo<v8::Value>& args);
58void Version(const v8::FunctionCallbackInfo<v8::Value>& args);
59v8::MaybeLocal<v8::String> ReadFile(v8::Isolate* isolate, const char* name);
60void ReportException(v8::Isolate* isolate, v8::TryCatch* handler);
61
62
63static bool run_shell;
64
65
66int main(int argc, char* argv[]) {
67  v8::V8::InitializeICUDefaultLocation(argv[0]);
68  v8::V8::InitializeExternalStartupData(argv[0]);
69  v8::Platform* platform = v8::platform::CreateDefaultPlatform();
70  v8::V8::InitializePlatform(platform);
71  v8::V8::Initialize();
72  v8::V8::SetFlagsFromCommandLine(&argc, argv, true);
73  v8::Isolate::CreateParams create_params;
74  create_params.array_buffer_allocator =
75      v8::ArrayBuffer::Allocator::NewDefaultAllocator();
76  v8::Isolate* isolate = v8::Isolate::New(create_params);
77  run_shell = (argc == 1);
78  int result;
79  {
80    v8::Isolate::Scope isolate_scope(isolate);
81    v8::HandleScope handle_scope(isolate);
82    v8::Local<v8::Context> context = CreateShellContext(isolate);
83    if (context.IsEmpty()) {
84      fprintf(stderr, "Error creating context\n");
85      return 1;
86    }
87    v8::Context::Scope context_scope(context);
88    result = RunMain(isolate, platform, argc, argv);
89    if (run_shell) RunShell(context, platform);
90  }
91  isolate->Dispose();
92  v8::V8::Dispose();
93  v8::V8::ShutdownPlatform();
94  delete platform;
95  delete create_params.array_buffer_allocator;
96  return result;
97}
98
99
100// Extracts a C string from a V8 Utf8Value.
101const char* ToCString(const v8::String::Utf8Value& value) {
102  return *value ? *value : "<string conversion failed>";
103}
104
105
106// Creates a new execution environment containing the built-in
107// functions.
108v8::Local<v8::Context> CreateShellContext(v8::Isolate* isolate) {
109  // Create a template for the global object.
110  v8::Local<v8::ObjectTemplate> global = v8::ObjectTemplate::New(isolate);
111  // Bind the global 'print' function to the C++ Print callback.
112  global->Set(
113      v8::String::NewFromUtf8(isolate, "print", v8::NewStringType::kNormal)
114          .ToLocalChecked(),
115      v8::FunctionTemplate::New(isolate, Print));
116  // Bind the global 'read' function to the C++ Read callback.
117  global->Set(v8::String::NewFromUtf8(
118                  isolate, "read", v8::NewStringType::kNormal).ToLocalChecked(),
119              v8::FunctionTemplate::New(isolate, Read));
120  // Bind the global 'load' function to the C++ Load callback.
121  global->Set(v8::String::NewFromUtf8(
122                  isolate, "load", v8::NewStringType::kNormal).ToLocalChecked(),
123              v8::FunctionTemplate::New(isolate, Load));
124  // Bind the 'quit' function
125  global->Set(v8::String::NewFromUtf8(
126                  isolate, "quit", v8::NewStringType::kNormal).ToLocalChecked(),
127              v8::FunctionTemplate::New(isolate, Quit));
128  // Bind the 'version' function
129  global->Set(
130      v8::String::NewFromUtf8(isolate, "version", v8::NewStringType::kNormal)
131          .ToLocalChecked(),
132      v8::FunctionTemplate::New(isolate, Version));
133
134  return v8::Context::New(isolate, NULL, global);
135}
136
137
138// The callback that is invoked by v8 whenever the JavaScript 'print'
139// function is called.  Prints its arguments on stdout separated by
140// spaces and ending with a newline.
141void Print(const v8::FunctionCallbackInfo<v8::Value>& args) {
142  bool first = true;
143  for (int i = 0; i < args.Length(); i++) {
144    v8::HandleScope handle_scope(args.GetIsolate());
145    if (first) {
146      first = false;
147    } else {
148      printf(" ");
149    }
150    v8::String::Utf8Value str(args[i]);
151    const char* cstr = ToCString(str);
152    printf("%s", cstr);
153  }
154  printf("\n");
155  fflush(stdout);
156}
157
158
159// The callback that is invoked by v8 whenever the JavaScript 'read'
160// function is called.  This function loads the content of the file named in
161// the argument into a JavaScript string.
162void Read(const v8::FunctionCallbackInfo<v8::Value>& args) {
163  if (args.Length() != 1) {
164    args.GetIsolate()->ThrowException(
165        v8::String::NewFromUtf8(args.GetIsolate(), "Bad parameters",
166                                v8::NewStringType::kNormal).ToLocalChecked());
167    return;
168  }
169  v8::String::Utf8Value file(args[0]);
170  if (*file == NULL) {
171    args.GetIsolate()->ThrowException(
172        v8::String::NewFromUtf8(args.GetIsolate(), "Error loading file",
173                                v8::NewStringType::kNormal).ToLocalChecked());
174    return;
175  }
176  v8::Local<v8::String> source;
177  if (!ReadFile(args.GetIsolate(), *file).ToLocal(&source)) {
178    args.GetIsolate()->ThrowException(
179        v8::String::NewFromUtf8(args.GetIsolate(), "Error loading file",
180                                v8::NewStringType::kNormal).ToLocalChecked());
181    return;
182  }
183  args.GetReturnValue().Set(source);
184}
185
186
187// The callback that is invoked by v8 whenever the JavaScript 'load'
188// function is called.  Loads, compiles and executes its argument
189// JavaScript file.
190void Load(const v8::FunctionCallbackInfo<v8::Value>& args) {
191  for (int i = 0; i < args.Length(); i++) {
192    v8::HandleScope handle_scope(args.GetIsolate());
193    v8::String::Utf8Value file(args[i]);
194    if (*file == NULL) {
195      args.GetIsolate()->ThrowException(
196          v8::String::NewFromUtf8(args.GetIsolate(), "Error loading file",
197                                  v8::NewStringType::kNormal).ToLocalChecked());
198      return;
199    }
200    v8::Local<v8::String> source;
201    if (!ReadFile(args.GetIsolate(), *file).ToLocal(&source)) {
202      args.GetIsolate()->ThrowException(
203          v8::String::NewFromUtf8(args.GetIsolate(), "Error loading file",
204                                  v8::NewStringType::kNormal).ToLocalChecked());
205      return;
206    }
207    if (!ExecuteString(args.GetIsolate(), source, args[i], false, false)) {
208      args.GetIsolate()->ThrowException(
209          v8::String::NewFromUtf8(args.GetIsolate(), "Error executing file",
210                                  v8::NewStringType::kNormal).ToLocalChecked());
211      return;
212    }
213  }
214}
215
216
217// The callback that is invoked by v8 whenever the JavaScript 'quit'
218// function is called.  Quits.
219void Quit(const v8::FunctionCallbackInfo<v8::Value>& args) {
220  // If not arguments are given args[0] will yield undefined which
221  // converts to the integer value 0.
222  int exit_code =
223      args[0]->Int32Value(args.GetIsolate()->GetCurrentContext()).FromMaybe(0);
224  fflush(stdout);
225  fflush(stderr);
226  exit(exit_code);
227}
228
229
230void Version(const v8::FunctionCallbackInfo<v8::Value>& args) {
231  args.GetReturnValue().Set(
232      v8::String::NewFromUtf8(args.GetIsolate(), v8::V8::GetVersion(),
233                              v8::NewStringType::kNormal).ToLocalChecked());
234}
235
236
237// Reads a file into a v8 string.
238v8::MaybeLocal<v8::String> ReadFile(v8::Isolate* isolate, const char* name) {
239  FILE* file = fopen(name, "rb");
240  if (file == NULL) return v8::MaybeLocal<v8::String>();
241
242  fseek(file, 0, SEEK_END);
243  size_t size = ftell(file);
244  rewind(file);
245
246  char* chars = new char[size + 1];
247  chars[size] = '\0';
248  for (size_t i = 0; i < size;) {
249    i += fread(&chars[i], 1, size - i, file);
250    if (ferror(file)) {
251      fclose(file);
252      return v8::MaybeLocal<v8::String>();
253    }
254  }
255  fclose(file);
256  v8::MaybeLocal<v8::String> result = v8::String::NewFromUtf8(
257      isolate, chars, v8::NewStringType::kNormal, static_cast<int>(size));
258  delete[] chars;
259  return result;
260}
261
262
263// Process remaining command line arguments and execute files
264int RunMain(v8::Isolate* isolate, v8::Platform* platform, int argc,
265            char* argv[]) {
266  for (int i = 1; i < argc; i++) {
267    const char* str = argv[i];
268    if (strcmp(str, "--shell") == 0) {
269      run_shell = true;
270    } else if (strcmp(str, "-f") == 0) {
271      // Ignore any -f flags for compatibility with the other stand-
272      // alone JavaScript engines.
273      continue;
274    } else if (strncmp(str, "--", 2) == 0) {
275      fprintf(stderr,
276              "Warning: unknown flag %s.\nTry --help for options\n", str);
277    } else if (strcmp(str, "-e") == 0 && i + 1 < argc) {
278      // Execute argument given to -e option directly.
279      v8::Local<v8::String> file_name =
280          v8::String::NewFromUtf8(isolate, "unnamed",
281                                  v8::NewStringType::kNormal).ToLocalChecked();
282      v8::Local<v8::String> source;
283      if (!v8::String::NewFromUtf8(isolate, argv[++i],
284                                   v8::NewStringType::kNormal)
285               .ToLocal(&source)) {
286        return 1;
287      }
288      bool success = ExecuteString(isolate, source, file_name, false, true);
289      while (v8::platform::PumpMessageLoop(platform, isolate)) continue;
290      if (!success) return 1;
291    } else {
292      // Use all other arguments as names of files to load and run.
293      v8::Local<v8::String> file_name =
294          v8::String::NewFromUtf8(isolate, str, v8::NewStringType::kNormal)
295              .ToLocalChecked();
296      v8::Local<v8::String> source;
297      if (!ReadFile(isolate, str).ToLocal(&source)) {
298        fprintf(stderr, "Error reading '%s'\n", str);
299        continue;
300      }
301      bool success = ExecuteString(isolate, source, file_name, false, true);
302      while (v8::platform::PumpMessageLoop(platform, isolate)) continue;
303      if (!success) return 1;
304    }
305  }
306  return 0;
307}
308
309
310// The read-eval-execute loop of the shell.
311void RunShell(v8::Local<v8::Context> context, v8::Platform* platform) {
312  fprintf(stderr, "V8 version %s [sample shell]\n", v8::V8::GetVersion());
313  static const int kBufferSize = 256;
314  // Enter the execution environment before evaluating any code.
315  v8::Context::Scope context_scope(context);
316  v8::Local<v8::String> name(
317      v8::String::NewFromUtf8(context->GetIsolate(), "(shell)",
318                              v8::NewStringType::kNormal).ToLocalChecked());
319  while (true) {
320    char buffer[kBufferSize];
321    fprintf(stderr, "> ");
322    char* str = fgets(buffer, kBufferSize, stdin);
323    if (str == NULL) break;
324    v8::HandleScope handle_scope(context->GetIsolate());
325    ExecuteString(
326        context->GetIsolate(),
327        v8::String::NewFromUtf8(context->GetIsolate(), str,
328                                v8::NewStringType::kNormal).ToLocalChecked(),
329        name, true, true);
330    while (v8::platform::PumpMessageLoop(platform, context->GetIsolate()))
331      continue;
332  }
333  fprintf(stderr, "\n");
334}
335
336
337// Executes a string within the current v8 context.
338bool ExecuteString(v8::Isolate* isolate, v8::Local<v8::String> source,
339                   v8::Local<v8::Value> name, bool print_result,
340                   bool report_exceptions) {
341  v8::HandleScope handle_scope(isolate);
342  v8::TryCatch try_catch(isolate);
343  v8::ScriptOrigin origin(name);
344  v8::Local<v8::Context> context(isolate->GetCurrentContext());
345  v8::Local<v8::Script> script;
346  if (!v8::Script::Compile(context, source, &origin).ToLocal(&script)) {
347    // Print errors that happened during compilation.
348    if (report_exceptions)
349      ReportException(isolate, &try_catch);
350    return false;
351  } else {
352    v8::Local<v8::Value> result;
353    if (!script->Run(context).ToLocal(&result)) {
354      assert(try_catch.HasCaught());
355      // Print errors that happened during execution.
356      if (report_exceptions)
357        ReportException(isolate, &try_catch);
358      return false;
359    } else {
360      assert(!try_catch.HasCaught());
361      if (print_result && !result->IsUndefined()) {
362        // If all went well and the result wasn't undefined then print
363        // the returned value.
364        v8::String::Utf8Value str(result);
365        const char* cstr = ToCString(str);
366        printf("%s\n", cstr);
367      }
368      return true;
369    }
370  }
371}
372
373
374void ReportException(v8::Isolate* isolate, v8::TryCatch* try_catch) {
375  v8::HandleScope handle_scope(isolate);
376  v8::String::Utf8Value exception(try_catch->Exception());
377  const char* exception_string = ToCString(exception);
378  v8::Local<v8::Message> message = try_catch->Message();
379  if (message.IsEmpty()) {
380    // V8 didn't provide any extra information about this error; just
381    // print the exception.
382    fprintf(stderr, "%s\n", exception_string);
383  } else {
384    // Print (filename):(line number): (message).
385    v8::String::Utf8Value filename(message->GetScriptOrigin().ResourceName());
386    v8::Local<v8::Context> context(isolate->GetCurrentContext());
387    const char* filename_string = ToCString(filename);
388    int linenum = message->GetLineNumber(context).FromJust();
389    fprintf(stderr, "%s:%i: %s\n", filename_string, linenum, exception_string);
390    // Print line of source code.
391    v8::String::Utf8Value sourceline(
392        message->GetSourceLine(context).ToLocalChecked());
393    const char* sourceline_string = ToCString(sourceline);
394    fprintf(stderr, "%s\n", sourceline_string);
395    // Print wavy underline (GetUnderline is deprecated).
396    int start = message->GetStartColumn(context).FromJust();
397    for (int i = 0; i < start; i++) {
398      fprintf(stderr, " ");
399    }
400    int end = message->GetEndColumn(context).FromJust();
401    for (int i = start; i < end; i++) {
402      fprintf(stderr, "^");
403    }
404    fprintf(stderr, "\n");
405    v8::Local<v8::Value> stack_trace_string;
406    if (try_catch->StackTrace(context).ToLocal(&stack_trace_string) &&
407        stack_trace_string->IsString() &&
408        v8::Local<v8::String>::Cast(stack_trace_string)->Length() > 0) {
409      v8::String::Utf8Value stack_trace(stack_trace_string);
410      const char* stack_trace_string = ToCString(stack_trace);
411      fprintf(stderr, "%s\n", stack_trace_string);
412    }
413  }
414}
415