sgjesse@chromium.org | b302e56 | 2010-02-03 11:26:59 +0000 | [diff] [blame^] | 1 | // Copyright 2009 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 <v8.h> |
| 29 | #include <v8-debug.h> |
| 30 | #include <fcntl.h> |
| 31 | #include <string.h> |
| 32 | #include <stdio.h> |
| 33 | #include <stdlib.h> |
| 34 | |
| 35 | /** |
| 36 | * This sample program should demonstrate certain aspects of debugging |
| 37 | * standalone V8-based application. |
| 38 | * |
| 39 | * The program reads input stream, processes it line by line and print |
| 40 | * the result to output. The actual processing is done by custom JavaScript |
| 41 | * script. The script is specified with command line parameters. |
| 42 | * |
| 43 | * The main cycle of the program will sequentially read lines from standard |
| 44 | * input, process them and print to standard output until input closes. |
| 45 | * There are 2 possible configuration in regard to main cycle. |
| 46 | * |
| 47 | * 1. The main cycle is on C++ side. Program should be run with |
| 48 | * --main-cycle-in-cpp option. Script must declare a function named |
| 49 | * "ProcessLine". The main cycle in C++ reads lines and calls this function |
| 50 | * for processing every time. This is a sample script: |
| 51 | |
| 52 | function ProcessLine(input_line) { |
| 53 | return ">>>" + input_line + "<<<"; |
| 54 | } |
| 55 | |
| 56 | * |
| 57 | * 2. The main cycle is in JavaScript. Program should be run with |
| 58 | * --main-cycle-in-js option. Script gets run one time at all and gets |
| 59 | * API of 2 global functions: "read_line" and "print". It should read input |
| 60 | * and print converted lines to output itself. This a sample script: |
| 61 | |
| 62 | while (true) { |
| 63 | var line = read_line(); |
| 64 | if (!line) { |
| 65 | break; |
| 66 | } |
| 67 | var res = line + " | " + line; |
| 68 | print(res); |
| 69 | } |
| 70 | |
| 71 | * |
| 72 | * When run with "-p" argument, the program starts V8 Debugger Agent and |
| 73 | * allows remote debugger to attach and debug JavaScript code. |
| 74 | * |
| 75 | * Interesting aspects: |
| 76 | * 1. Wait for remote debugger to attach |
| 77 | * Normally the program compiles custom script and immediately runs it. |
| 78 | * If programmer needs to debug script from the very beginning, he should |
| 79 | * run this sample program with "--wait-for-connection" command line parameter. |
| 80 | * This way V8 will suspend on the first statement and wait for |
| 81 | * debugger to attach. |
| 82 | * |
| 83 | * 2. Unresponsive V8 |
| 84 | * V8 Debugger Agent holds a connection with remote debugger, but it does |
| 85 | * respond only when V8 is running some script. In particular, when this program |
| 86 | * is waiting for input, all requests from debugger get deferred until V8 |
| 87 | * is called again. See how "--callback" command-line parameter in this sample |
| 88 | * fixes this issue. |
| 89 | */ |
| 90 | |
| 91 | enum MainCycleType { |
| 92 | CycleInCpp, |
| 93 | CycleInJs |
| 94 | }; |
| 95 | |
| 96 | const char* ToCString(const v8::String::Utf8Value& value); |
| 97 | void ReportException(v8::TryCatch* handler); |
| 98 | v8::Handle<v8::String> ReadFile(const char* name); |
| 99 | v8::Handle<v8::String> ReadLine(); |
| 100 | |
| 101 | v8::Handle<v8::Value> Print(const v8::Arguments& args); |
| 102 | v8::Handle<v8::Value> ReadLine(const v8::Arguments& args); |
| 103 | bool RunCppCycle(v8::Handle<v8::Script> script, v8::Local<v8::Context> context, |
| 104 | bool report_exceptions); |
| 105 | |
| 106 | v8::Persistent<v8::Context> debug_message_context; |
| 107 | |
| 108 | |
| 109 | void DispatchDebugMessages() { |
| 110 | // We are in some random thread. We should already have v8::Locker acquired |
| 111 | // (we requested this when registered this callback). We was called |
| 112 | // because new debug messages arrived; they may have already been processed, |
| 113 | // but we shouldn't worry about this. |
| 114 | // |
| 115 | // All we have to do is to set context and call ProcessDebugMessages. |
| 116 | // |
| 117 | // We should decide which V8 context to use here. This is important for |
| 118 | // "evaluate" command, because it must be executed some context. |
| 119 | // In our sample we have only one context, so there is nothing really to |
| 120 | // think about. |
| 121 | v8::Context::Scope scope(debug_message_context); |
| 122 | |
| 123 | v8::Debug::ProcessDebugMessages(); |
| 124 | } |
| 125 | |
| 126 | |
| 127 | int RunMain(int argc, char* argv[]) { |
| 128 | v8::V8::SetFlagsFromCommandLine(&argc, argv, true); |
| 129 | v8::HandleScope handle_scope; |
| 130 | |
| 131 | v8::Handle<v8::String> script_source(NULL); |
| 132 | v8::Handle<v8::Value> script_name(NULL); |
| 133 | int script_param_counter = 0; |
| 134 | |
| 135 | int port_number = -1; |
| 136 | bool wait_for_connection = false; |
| 137 | bool support_callback = false; |
| 138 | MainCycleType cycle_type = CycleInCpp; |
| 139 | |
| 140 | for (int i = 1; i < argc; i++) { |
| 141 | const char* str = argv[i]; |
| 142 | if (strcmp(str, "-f") == 0) { |
| 143 | // Ignore any -f flags for compatibility with the other stand- |
| 144 | // alone JavaScript engines. |
| 145 | continue; |
| 146 | } else if (strcmp(str, "--callback") == 0) { |
| 147 | support_callback = true; |
| 148 | } else if (strcmp(str, "--wait-for-connection") == 0) { |
| 149 | wait_for_connection = true; |
| 150 | } else if (strcmp(str, "--main-cycle-in-cpp") == 0) { |
| 151 | cycle_type = CycleInCpp; |
| 152 | } else if (strcmp(str, "--main-cycle-in-js") == 0) { |
| 153 | cycle_type = CycleInJs; |
| 154 | } else if (strcmp(str, "-p") == 0 && i + 1 < argc) { |
| 155 | port_number = atoi(argv[i + 1]); |
| 156 | i++; |
| 157 | } else if (strncmp(str, "--", 2) == 0) { |
| 158 | printf("Warning: unknown flag %s.\nTry --help for options\n", str); |
| 159 | } else if (strcmp(str, "-e") == 0 && i + 1 < argc) { |
| 160 | script_source = v8::String::New(argv[i + 1]); |
| 161 | script_name = v8::String::New("unnamed"); |
| 162 | i++; |
| 163 | script_param_counter++; |
| 164 | } else { |
| 165 | // Use argument as a name of file to load. |
| 166 | script_source = ReadFile(str); |
| 167 | script_name = v8::String::New(str); |
| 168 | if (script_source.IsEmpty()) { |
| 169 | printf("Error reading '%s'\n", str); |
| 170 | return 1; |
| 171 | } |
| 172 | script_param_counter++; |
| 173 | } |
| 174 | } |
| 175 | |
| 176 | if (script_param_counter == 0) { |
| 177 | printf("Script is not specified\n"); |
| 178 | return 1; |
| 179 | } |
| 180 | if (script_param_counter != 1) { |
| 181 | printf("Only one script may be specified\n"); |
| 182 | return 1; |
| 183 | } |
| 184 | |
| 185 | // Create a template for the global object. |
| 186 | v8::Handle<v8::ObjectTemplate> global = v8::ObjectTemplate::New(); |
| 187 | |
| 188 | // Bind the global 'print' function to the C++ Print callback. |
| 189 | global->Set(v8::String::New("print"), v8::FunctionTemplate::New(Print)); |
| 190 | |
| 191 | if (cycle_type == CycleInJs) { |
| 192 | // Bind the global 'read_line' function to the C++ Print callback. |
| 193 | global->Set(v8::String::New("read_line"), |
| 194 | v8::FunctionTemplate::New(ReadLine)); |
| 195 | } |
| 196 | |
| 197 | // Create a new execution environment containing the built-in |
| 198 | // functions |
| 199 | v8::Handle<v8::Context> context = v8::Context::New(NULL, global); |
| 200 | debug_message_context = v8::Persistent<v8::Context>::New(context); |
| 201 | |
| 202 | |
| 203 | // Enter the newly created execution environment. |
| 204 | v8::Context::Scope context_scope(context); |
| 205 | |
| 206 | v8::Locker locker; |
| 207 | |
| 208 | if (support_callback) { |
| 209 | v8::Debug::SetDebugMessageDispatchHandler(DispatchDebugMessages, true); |
| 210 | } |
| 211 | |
| 212 | if (port_number != -1) { |
| 213 | const char* auto_break_param = "--debugger_auto_break"; |
| 214 | v8::V8::SetFlagsFromString(auto_break_param, strlen(auto_break_param)); |
| 215 | v8::Debug::EnableAgent("lineprocessor", port_number, wait_for_connection); |
| 216 | } |
| 217 | |
| 218 | bool report_exceptions = true; |
| 219 | |
| 220 | v8::Handle<v8::Script> script; |
| 221 | { |
| 222 | // Compile script in try/catch context. |
| 223 | v8::TryCatch try_catch; |
| 224 | script = v8::Script::Compile(script_source, script_name); |
| 225 | if (script.IsEmpty()) { |
| 226 | // Print errors that happened during compilation. |
| 227 | if (report_exceptions) |
| 228 | ReportException(&try_catch); |
| 229 | return 1; |
| 230 | } |
| 231 | } |
| 232 | |
| 233 | { |
| 234 | v8::TryCatch try_catch; |
| 235 | |
| 236 | script->Run(); |
| 237 | if (try_catch.HasCaught()) { |
| 238 | if (report_exceptions) |
| 239 | ReportException(&try_catch); |
| 240 | return 1; |
| 241 | } |
| 242 | } |
| 243 | |
| 244 | if (cycle_type == CycleInCpp) { |
| 245 | bool res = RunCppCycle(script, v8::Context::GetCurrent(), |
| 246 | report_exceptions); |
| 247 | return !res; |
| 248 | } else { |
| 249 | // All is already done. |
| 250 | } |
| 251 | return 0; |
| 252 | } |
| 253 | |
| 254 | |
| 255 | bool RunCppCycle(v8::Handle<v8::Script> script, v8::Local<v8::Context> context, |
| 256 | bool report_exceptions) { |
| 257 | v8::Locker lock; |
| 258 | |
| 259 | v8::Handle<v8::String> fun_name = v8::String::New("ProcessLine"); |
| 260 | v8::Handle<v8::Value> process_val = |
| 261 | v8::Context::GetCurrent()->Global()->Get(fun_name); |
| 262 | |
| 263 | // If there is no Process function, or if it is not a function, |
| 264 | // bail out |
| 265 | if (!process_val->IsFunction()) { |
| 266 | printf("Error: Script does not declare 'ProcessLine' global function.\n"); |
| 267 | return 1; |
| 268 | } |
| 269 | |
| 270 | // It is a function; cast it to a Function |
| 271 | v8::Handle<v8::Function> process_fun = |
| 272 | v8::Handle<v8::Function>::Cast(process_val); |
| 273 | |
| 274 | |
| 275 | while (!feof(stdin)) { |
| 276 | v8::HandleScope handle_scope; |
| 277 | |
| 278 | v8::Handle<v8::String> input_line = ReadLine(); |
| 279 | if (input_line == v8::Undefined()) { |
| 280 | continue; |
| 281 | } |
| 282 | |
| 283 | const int argc = 1; |
| 284 | v8::Handle<v8::Value> argv[argc] = { input_line }; |
| 285 | |
| 286 | v8::Handle<v8::Value> result; |
| 287 | { |
| 288 | v8::TryCatch try_catch; |
| 289 | result = process_fun->Call(v8::Context::GetCurrent()->Global(), |
| 290 | argc, argv); |
| 291 | if (try_catch.HasCaught()) { |
| 292 | if (report_exceptions) |
| 293 | ReportException(&try_catch); |
| 294 | return false; |
| 295 | } |
| 296 | } |
| 297 | v8::String::Utf8Value str(result); |
| 298 | const char* cstr = ToCString(str); |
| 299 | printf("%s\n", cstr); |
| 300 | } |
| 301 | |
| 302 | return true; |
| 303 | } |
| 304 | |
| 305 | int main(int argc, char* argv[]) { |
| 306 | int result = RunMain(argc, argv); |
| 307 | v8::V8::Dispose(); |
| 308 | return result; |
| 309 | } |
| 310 | |
| 311 | |
| 312 | // Extracts a C string from a V8 Utf8Value. |
| 313 | const char* ToCString(const v8::String::Utf8Value& value) { |
| 314 | return *value ? *value : "<string conversion failed>"; |
| 315 | } |
| 316 | |
| 317 | |
| 318 | // Reads a file into a v8 string. |
| 319 | v8::Handle<v8::String> ReadFile(const char* name) { |
| 320 | FILE* file = fopen(name, "rb"); |
| 321 | if (file == NULL) return v8::Handle<v8::String>(); |
| 322 | |
| 323 | fseek(file, 0, SEEK_END); |
| 324 | int size = ftell(file); |
| 325 | rewind(file); |
| 326 | |
| 327 | char* chars = new char[size + 1]; |
| 328 | chars[size] = '\0'; |
| 329 | for (int i = 0; i < size;) { |
| 330 | int read = fread(&chars[i], 1, size - i, file); |
| 331 | i += read; |
| 332 | } |
| 333 | fclose(file); |
| 334 | v8::Handle<v8::String> result = v8::String::New(chars, size); |
| 335 | delete[] chars; |
| 336 | return result; |
| 337 | } |
| 338 | |
| 339 | |
| 340 | void ReportException(v8::TryCatch* try_catch) { |
| 341 | v8::HandleScope handle_scope; |
| 342 | v8::String::Utf8Value exception(try_catch->Exception()); |
| 343 | const char* exception_string = ToCString(exception); |
| 344 | v8::Handle<v8::Message> message = try_catch->Message(); |
| 345 | if (message.IsEmpty()) { |
| 346 | // V8 didn't provide any extra information about this error; just |
| 347 | // print the exception. |
| 348 | printf("%s\n", exception_string); |
| 349 | } else { |
| 350 | // Print (filename):(line number): (message). |
| 351 | v8::String::Utf8Value filename(message->GetScriptResourceName()); |
| 352 | const char* filename_string = ToCString(filename); |
| 353 | int linenum = message->GetLineNumber(); |
| 354 | printf("%s:%i: %s\n", filename_string, linenum, exception_string); |
| 355 | // Print line of source code. |
| 356 | v8::String::Utf8Value sourceline(message->GetSourceLine()); |
| 357 | const char* sourceline_string = ToCString(sourceline); |
| 358 | printf("%s\n", sourceline_string); |
| 359 | // Print wavy underline (GetUnderline is deprecated). |
| 360 | int start = message->GetStartColumn(); |
| 361 | for (int i = 0; i < start; i++) { |
| 362 | printf(" "); |
| 363 | } |
| 364 | int end = message->GetEndColumn(); |
| 365 | for (int i = start; i < end; i++) { |
| 366 | printf("^"); |
| 367 | } |
| 368 | printf("\n"); |
| 369 | } |
| 370 | } |
| 371 | |
| 372 | |
| 373 | // The callback that is invoked by v8 whenever the JavaScript 'print' |
| 374 | // function is called. Prints its arguments on stdout separated by |
| 375 | // spaces and ending with a newline. |
| 376 | v8::Handle<v8::Value> Print(const v8::Arguments& args) { |
| 377 | bool first = true; |
| 378 | for (int i = 0; i < args.Length(); i++) { |
| 379 | v8::HandleScope handle_scope; |
| 380 | if (first) { |
| 381 | first = false; |
| 382 | } else { |
| 383 | printf(" "); |
| 384 | } |
| 385 | v8::String::Utf8Value str(args[i]); |
| 386 | const char* cstr = ToCString(str); |
| 387 | printf("%s", cstr); |
| 388 | } |
| 389 | printf("\n"); |
| 390 | fflush(stdout); |
| 391 | return v8::Undefined(); |
| 392 | } |
| 393 | |
| 394 | |
| 395 | // The callback that is invoked by v8 whenever the JavaScript 'read_line' |
| 396 | // function is called. Reads a string from standard input and returns. |
| 397 | v8::Handle<v8::Value> ReadLine(const v8::Arguments& args) { |
| 398 | if (args.Length() > 0) { |
| 399 | return v8::ThrowException(v8::String::New("Unexpected arguments")); |
| 400 | } |
| 401 | return ReadLine(); |
| 402 | } |
| 403 | |
| 404 | v8::Handle<v8::String> ReadLine() { |
| 405 | const int kBufferSize = 1024 + 1; |
| 406 | char buffer[kBufferSize]; |
| 407 | |
| 408 | char* res; |
| 409 | { |
| 410 | v8::Unlocker unlocker; |
| 411 | res = fgets(buffer, kBufferSize, stdin); |
| 412 | } |
| 413 | if (res == NULL) { |
| 414 | v8::Handle<v8::Primitive> t = v8::Undefined(); |
| 415 | return reinterpret_cast<v8::Handle<v8::String>&>(t); |
| 416 | } |
| 417 | // remove newline char |
| 418 | for (char* pos = buffer; *pos != '\0'; pos++) { |
| 419 | if (*pos == '\n') { |
| 420 | *pos = '\0'; |
| 421 | break; |
| 422 | } |
| 423 | } |
| 424 | return v8::String::New(buffer); |
| 425 | } |