// 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); v8::MaybeLocal<v8::String> ReadFile(v8::Isolate* isolate, const char* name); void ReportException(v8::Isolate* isolate, v8::TryCatch* handler); static bool run_shell; int main(int argc, char* argv[]) { v8::V8::InitializeICUDefaultLocation(argv[0]); v8::V8::InitializeExternalStartupData(argv[0]); std::unique_ptr<v8::Platform> platform = v8::platform::NewDefaultPlatform(); v8::V8::InitializePlatform(platform.get()); 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); 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.get(), argc, argv); if (run_shell) RunShell(context, platform.get()); } isolate->Dispose(); v8::V8::Dispose(); v8::V8::ShutdownPlatform(); 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>"; } // 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::NewFromUtf8Literal(isolate, "print"), v8::FunctionTemplate::New(isolate, Print)); // Bind the global 'read' function to the C++ Read callback. global->Set(v8::String::NewFromUtf8Literal(isolate, "read"), v8::FunctionTemplate::New(isolate, Read)); // Bind the global 'load' function to the C++ Load callback. global->Set(v8::String::NewFromUtf8Literal(isolate, "load"), v8::FunctionTemplate::New(isolate, Load)); // Bind the 'quit' function global->Set(v8::String::NewFromUtf8Literal(isolate, "quit"), v8::FunctionTemplate::New(isolate, Quit)); // Bind the 'version' function global->Set(v8::String::NewFromUtf8Literal(isolate, "version"), v8::FunctionTemplate::New(isolate, Version)); 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.GetIsolate(), 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::NewFromUtf8Literal(args.GetIsolate(), "Bad parameters")); return; } v8::String::Utf8Value file(args.GetIsolate(), args[0]); if (*file == NULL) { args.GetIsolate()->ThrowException(v8::String::NewFromUtf8Literal( args.GetIsolate(), "Error loading file")); return; } v8::Local<v8::String> source; if (!ReadFile(args.GetIsolate(), *file).ToLocal(&source)) { args.GetIsolate()->ThrowException(v8::String::NewFromUtf8Literal( args.GetIsolate(), "Error loading file")); 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.GetIsolate(), args[i]); if (*file == NULL) { args.GetIsolate()->ThrowException(v8::String::NewFromUtf8Literal( args.GetIsolate(), "Error loading file")); return; } v8::Local<v8::String> source; if (!ReadFile(args.GetIsolate(), *file).ToLocal(&source)) { args.GetIsolate()->ThrowException(v8::String::NewFromUtf8Literal( args.GetIsolate(), "Error loading file")); return; } if (!ExecuteString(args.GetIsolate(), source, args[i], false, false)) { args.GetIsolate()->ThrowException(v8::String::NewFromUtf8Literal( args.GetIsolate(), "Error executing file")); 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()) .ToLocalChecked()); } // Reads a file into a v8 string. v8::MaybeLocal<v8::String> ReadFile(v8::Isolate* isolate, const char* name) { FILE* file = fopen(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[]) { 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::NewFromUtf8Literal(isolate, "unnamed"); v8::Local<v8::String> source; if (!v8::String::NewFromUtf8(isolate, argv[++i]).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).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::NewFromUtf8Literal(context->GetIsolate(), "(shell)")); 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).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(isolate, 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(isolate, 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(isolate, 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( isolate, 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(isolate, stack_trace_string); const char* stack_trace_string = ToCString(stack_trace); fprintf(stderr, "%s\n", stack_trace_string); } } }