1 /* 2 * Copyright 2013 Google Inc. 3 * 4 * 5 * Use of this source code is governed by a BSD-style license that can be 6 * found in the LICENSE file. 7 * 8 */ 9 #include "Global.h" 10 11 #include "SkWindow.h" 12 #include "SkEvent.h" 13 14 15 Global* Global::gGlobal = NULL; 16 17 // Extracts a C string from a V8 Utf8Value. 18 static const char* to_cstring(const v8::String::Utf8Value& value) { 19 return *value ? *value : "<string conversion failed>"; 20 } 21 22 int32_t Global::getNextTimerID() { 23 do { 24 fLastTimerID++; 25 if (fLastTimerID < 0) { 26 fLastTimerID = 0; 27 } 28 } while (fTimeouts.find(fLastTimerID) != fTimeouts.end()); 29 return fLastTimerID; 30 } 31 32 // Slight modification to an original function found in the V8 sample shell.cc. 33 void Global::reportException(v8::TryCatch* tryCatch) { 34 v8::HandleScope handleScope(fIsolate); 35 v8::String::Utf8Value exception(tryCatch->Exception()); 36 const char* exceptionString = to_cstring(exception); 37 v8::Handle<v8::Message> message = tryCatch->Message(); 38 if (message.IsEmpty()) { 39 // V8 didn't provide any extra information about this error; just 40 // print the exception. 41 fprintf(stderr, "%s\n", exceptionString); 42 } else { 43 // Print (filename):(line number): (message). 44 v8::String::Utf8Value filename(message->GetScriptOrigin().ResourceName()); 45 const char* filenameString = to_cstring(filename); 46 int linenum = message->GetLineNumber(); 47 fprintf(stderr, 48 "%s:%i: %s\n", filenameString, linenum, exceptionString); 49 // Print line of source code. 50 v8::String::Utf8Value sourceline(message->GetSourceLine()); 51 const char* sourceLineString = to_cstring(sourceline); 52 fprintf(stderr, "%s\n", sourceLineString); 53 // Print wavy underline. 54 int start = message->GetStartColumn(); 55 for (int i = 0; i < start; i++) { 56 fprintf(stderr, " "); 57 } 58 int end = message->GetEndColumn(); 59 for (int i = start; i < end; i++) { 60 fprintf(stderr, "^"); 61 } 62 fprintf(stderr, "\n"); 63 v8::String::Utf8Value stackTrace(tryCatch->StackTrace()); 64 if (stackTrace.length() > 0) { 65 const char* stackTraceString = to_cstring(stackTrace); 66 fprintf(stderr, "%s\n", stackTraceString); 67 } 68 } 69 } 70 71 // The callback that implements the JavaScript 'inval' function. 72 // Invalidates the current window, forcing a redraw. 73 // 74 // JS: inval(); 75 void Global::Inval(const v8::FunctionCallbackInfo<v8::Value>& args) { 76 gGlobal->getWindow()->inval(NULL); 77 } 78 79 // The callback that is invoked by v8 whenever the JavaScript 'print' 80 // function is called. Prints its arguments on stdout separated by 81 // spaces and ending with a newline. 82 // 83 // JS: print("foo", "bar"); 84 void Global::Print(const v8::FunctionCallbackInfo<v8::Value>& args) { 85 bool first = true; 86 v8::HandleScope handleScope(args.GetIsolate()); 87 for (int i = 0; i < args.Length(); i++) { 88 if (first) { 89 first = false; 90 } else { 91 printf(" "); 92 } 93 v8::String::Utf8Value str(args[i]); 94 printf("%s", to_cstring(str)); 95 } 96 printf("\n"); 97 fflush(stdout); 98 } 99 100 // The callback that is invoked by v8 whenever the JavaScript 'setTimeout' 101 // function is called. 102 // 103 // JS: setTimeout(on_timeout, 500); 104 void Global::SetTimeout(const v8::FunctionCallbackInfo<v8::Value>& args) { 105 if (args.Length() != 2) { 106 args.GetIsolate()->ThrowException( 107 v8::String::NewFromUtf8( 108 args.GetIsolate(), "Error: 2 arguments required.")); 109 return; 110 } 111 112 // Pull out the first arg, make sure it's a function. 113 if (!args[0]->IsFunction()) { 114 printf("Not a function passed to setTimeout.\n"); 115 return; 116 } 117 v8::Handle<v8::Function> timeoutFn = v8::Handle<v8::Function>::Cast(args[0]); 118 119 double delay = args[1]->NumberValue(); 120 int32_t id = gGlobal->getNextTimerID(); 121 122 gGlobal->fTimeouts[id].Reset(gGlobal->fIsolate, timeoutFn); 123 124 // Create an SkEvent and add it with the right delay. 125 SkEvent* evt = new SkEvent(); 126 evt->setTargetProc(Global::TimeOutProc); 127 evt->setFast32(id); 128 evt->postDelay(delay); 129 130 args.GetReturnValue().Set(v8::Integer::New(gGlobal->fIsolate, id)); 131 } 132 133 // Callback function for SkEvents used to implement timeouts. 134 bool Global::TimeOutProc(const SkEvent& evt) { 135 // Create a handle scope to keep the temporary object references. 136 v8::HandleScope handleScope(gGlobal->getIsolate()); 137 138 // Create a local context from our global context. 139 v8::Local<v8::Context> context = gGlobal->getContext(); 140 141 // Enter the context so all the remaining operations take place there. 142 v8::Context::Scope contextScope(context); 143 144 // Set up an exception handler before calling the Process function. 145 v8::TryCatch tryCatch; 146 147 int32_t id = evt.getFast32(); 148 if (gGlobal->fTimeouts.find(gGlobal->fLastTimerID) == gGlobal->fTimeouts.end()) { 149 printf("Not a valid timer ID.\n"); 150 return true; 151 } 152 153 const int argc = 0; 154 v8::Local<v8::Function> onTimeout = 155 v8::Local<v8::Function>::New(gGlobal->getIsolate(), gGlobal->fTimeouts[id]); 156 v8::Handle<v8::Value> result = onTimeout->Call(context->Global(), argc, NULL); 157 gGlobal->fTimeouts.erase(id); 158 159 // Handle any exceptions or output. 160 if (result.IsEmpty()) { 161 SkASSERT(tryCatch.HasCaught()); 162 // Print errors that happened during execution. 163 gGlobal->reportException(&tryCatch); 164 } else { 165 SkASSERT(!tryCatch.HasCaught()); 166 if (!result->IsUndefined()) { 167 // If all went well and the result wasn't undefined then print the 168 // returned value. 169 v8::String::Utf8Value str(result); 170 const char* cstr = to_cstring(str); 171 printf("%s\n", cstr); 172 } 173 } 174 return true; 175 } 176 177 // Creates a new execution environment containing the built-in functions. 178 v8::Handle<v8::Context> Global::createRootContext() { 179 // Create a template for the global object. 180 v8::Handle<v8::ObjectTemplate> global = v8::ObjectTemplate::New(); 181 182 global->Set(v8::String::NewFromUtf8(fIsolate, "print"), 183 v8::FunctionTemplate::New(fIsolate, Global::Print)); 184 global->Set(v8::String::NewFromUtf8(fIsolate, "setTimeout"), 185 v8::FunctionTemplate::New(fIsolate, Global::SetTimeout)); 186 global->Set(v8::String::NewFromUtf8(fIsolate, "inval"), 187 v8::FunctionTemplate::New(fIsolate, Global::Inval)); 188 189 190 return v8::Context::New(fIsolate, NULL, global); 191 } 192 193 void Global::initialize() { 194 // Create a stack-allocated handle scope. 195 v8::HandleScope handleScope(fIsolate); 196 197 // Create a new context. 198 v8::Handle<v8::Context> context = this->createRootContext(); 199 200 // Make the context persistent. 201 fContext.Reset(fIsolate, context); 202 } 203 204 205 // Creates the root context, parses the script into it, then stores the 206 // context in a global. 207 // 208 // TODO(jcgregorio) Currently only handles one script. Need to move 209 // createRootContext to another call that's only done once. 210 bool Global::parseScript(const char script[]) { 211 212 // Create a stack-allocated handle scope. 213 v8::HandleScope handleScope(fIsolate); 214 215 // Get the global context. 216 v8::Handle<v8::Context> context = this->getContext(); 217 218 // Enter the scope so all operations take place in the scope. 219 v8::Context::Scope contextScope(context); 220 221 v8::TryCatch tryCatch; 222 223 // Compile the source code. 224 v8::Handle<v8::String> source = v8::String::NewFromUtf8(fIsolate, script); 225 v8::Handle<v8::Script> compiledScript = v8::Script::Compile(source); 226 227 if (compiledScript.IsEmpty()) { 228 // Print errors that happened during compilation. 229 this->reportException(&tryCatch); 230 return false; 231 } 232 233 // Try running it now to create the onDraw function. 234 v8::Handle<v8::Value> result = compiledScript->Run(); 235 236 // Handle any exceptions or output. 237 if (result.IsEmpty()) { 238 SkASSERT(tryCatch.HasCaught()); 239 // Print errors that happened during execution. 240 this->reportException(&tryCatch); 241 return false; 242 } 243 244 return true; 245 } 246
