Introduce gin_shell

gin/modules/module_registry.cc

Index: gin/modules/module_registry.cc
diff --git a/gin/modules/module_registry.cc b/gin/modules/module_registry.cc
index aad2135b0e1114aa634366d7da39e91831946bfe..1ee8e3cbe8fb92aa36f4852f7d7d92ffe410a63b 100644
--- a/gin/modules/module_registry.cc
+++ b/gin/modules/module_registry.cc
@@ -12,10 +12,20 @@
 #include "gin/per_isolate_data.h"
 #include "gin/wrapper_info.h"
 
+using v8::Context;
 using v8::External;
+using v8::Function;
+using v8::FunctionCallbackInfo;
+using v8::FunctionTemplate;
 using v8::Handle;
 using v8::Isolate;
+using v8::Local;
+using v8::Object;
 using v8::ObjectTemplate;
+using v8::Persistent;
+using v8::StackTrace;
+using v8::String;
+using v8::Value;
 
 namespace gin {
 
@@ -25,12 +35,19 @@ struct PendingModule {
 
   std::string id;
   std::vector<std::string> dependencies;
-  v8::Persistent<v8::Value> factory;
+  Persistent<Value> factory;
 };
 
+PendingModule::PendingModule() {
+}
+
+PendingModule::~PendingModule() {
+  factory.Reset();
+}
+
 namespace {
 
-void Define(const v8::FunctionCallbackInfo<v8::Value>& info) {
+void Define(const FunctionCallbackInfo<Value>& info) {
   Arguments args(info);
 
   if (!info.Length())
@@ -38,7 +55,7 @@ void Define(const v8::FunctionCallbackInfo<v8::Value>& info) {
 
   std::string id;
   std::vector<std::string> dependencies;
-  Handle<v8::Value> factory;
+  Handle<Value> factory;
 
   if (args.PeekNext()->IsString())
     args.GetNext(&id);
@@ -47,141 +64,165 @@ void Define(const v8::FunctionCallbackInfo<v8::Value>& info) {
   if (!args.GetNext(&factory))
     return args.ThrowError();
 
-  PendingModule* pending = new PendingModule;
+  scoped_ptr<PendingModule> pending(new PendingModule);
   pending->id = id;
   pending->dependencies = dependencies;
   pending->factory.Reset(args.isolate(), factory);
 
   ModuleRegistry* registry =
       ModuleRegistry::From(args.isolate()->GetCurrentContext());
-  registry->AddPendingModule(args.isolate(), pending);
+  registry->AddPendingModule(args.isolate(), pending.Pass());
 }
 
 WrapperInfo g_wrapper_info = {};
 
-v8::Local<v8::FunctionTemplate> GetDefineTemplate(v8::Isolate* isolate) {
+Local<FunctionTemplate> GetDefineTemplate(Isolate* isolate) {
   PerIsolateData* data = PerIsolateData::From(isolate);
-  v8::Local<v8::FunctionTemplate> templ = data->GetFunctionTemplate(
+  Local<FunctionTemplate> templ = data->GetFunctionTemplate(
       &g_wrapper_info);
   if (templ.IsEmpty()) {
-    templ = v8::FunctionTemplate::New(Define);
+    templ = FunctionTemplate::New(Define);
     data->SetFunctionTemplate(&g_wrapper_info, templ);
   }
   return templ;
 }
 
-Handle<v8::String> GetHiddenValueKey(v8::Isolate* isolate) {
+Handle<String> GetHiddenValueKey(Isolate* isolate) {
   return StringToSymbol(isolate, "::gin::ModuleRegistry");
 }
 
-}  // namespace
-
-
-PendingModule::PendingModule() {
+std::string GetImplicitModuleName(const std::string& explicit_name) {
+  if (!explicit_name.empty())
+    return explicit_name;
+  std::string implicit_name;
+  Handle<StackTrace> trace = StackTrace::CurrentStackTrace(1);
+  Handle<String> script_name = trace->GetFrame(0)->GetScriptName();
+  if (!script_name.IsEmpty())
+    ConvertFromV8(script_name, &implicit_name);
+  return implicit_name;
 }
 
-PendingModule::~PendingModule() {
-  factory.Reset();
-}
+}  // namespace
 
-ModuleRegistry::ModuleRegistry(v8::Isolate* isolate)
-    : modules_(isolate, v8::Object::New()) {
+ModuleRegistry::ModuleRegistry(Isolate* isolate)
+    : modules_(isolate, Object::New()) {
 }
 
 ModuleRegistry::~ModuleRegistry() {
-  for (PendingModuleList::iterator it = pending_modules_.begin();
-       it != pending_modules_.end(); ++it) {
-    delete *it;
-  }
   modules_.Reset();
 }
 
-void ModuleRegistry::RegisterGlobals(v8::Isolate* isolate,
-                                     Handle<v8::ObjectTemplate> templ) {
+void ModuleRegistry::RegisterGlobals(Isolate* isolate,
+                                     Handle<ObjectTemplate> templ) {
   templ->Set(StringToSymbol(isolate, "define"), GetDefineTemplate(isolate));
 }
 
-void ModuleRegistry::AddBuiltinModule(Isolate* isolate,
-                                      const std::string& id,
-                                      Handle<ObjectTemplate> templ) {
-  DCHECK(!id.empty());
-  Handle<v8::Object> modules = v8::Local<v8::Object>::New(isolate, modules_);
-  modules->Set(StringToV8(isolate, id), templ->NewInstance());
-}
-
-ModuleRegistry* ModuleRegistry::From(Handle<v8::Context> context) {
-  v8::Isolate* isolate = context->GetIsolate();
-  Handle<v8::String> key = GetHiddenValueKey(isolate);
-  Handle<v8::Value> value = context->Global()->GetHiddenValue(key);
-  Handle<v8::External> external;
+ModuleRegistry* ModuleRegistry::From(Handle<Context> context) {
+  Isolate* isolate = context->GetIsolate();
+  Handle<String> key = GetHiddenValueKey(isolate);
+  Handle<Value> value = context->Global()->GetHiddenValue(key);
+  Handle<External> external;
   if (value.IsEmpty() || !ConvertFromV8(value, &external)) {
     PerContextData* data = PerContextData::From(context);
     if (!data)
       return NULL;
     ModuleRegistry* registry = new ModuleRegistry(isolate);
-    context->Global()->SetHiddenValue(key, v8::External::New(registry));
+    context->Global()->SetHiddenValue(key, External::New(registry));
     data->AddSupplement(scoped_ptr<ContextSupplement>(registry));
     return registry;
   }
   return static_cast<ModuleRegistry*>(external->Value());
 }
 
-void ModuleRegistry::AddPendingModule(v8::Isolate* isolate,
-                                      PendingModule* pending) {
-  if (AttemptToLoad(isolate, pending))
-    AttemptToLoadPendingModules(isolate);
+void ModuleRegistry::AddBuiltinModule(Isolate* isolate,
+                                      const std::string& id,
+                                      Handle<ObjectTemplate> templ) {
+  DCHECK(!id.empty());
+  RegisterModule(isolate, id, templ->NewInstance());
 }
 
-void ModuleRegistry::Detach(Handle<v8::Context> context) {
-  context->Global()->SetHiddenValue(GetHiddenValueKey(context->GetIsolate()),
-                                    Handle<v8::Value>());
+void ModuleRegistry::AddPendingModule(Isolate* isolate,
+                                      scoped_ptr<PendingModule> pending) {
+  AttemptToLoad(isolate, pending.Pass());
 }
 
-bool ModuleRegistry::AttemptToLoad(v8::Isolate* isolate,
-                                   PendingModule* pending) {
-  Handle<v8::Object> modules = v8::Local<v8::Object>::New(isolate, modules_);
-  Handle<v8::String> key = StringToV8(isolate, pending->id);
+void ModuleRegistry::RegisterModule(Isolate* isolate,
+                                    const std::string& id,
+                                    Handle<Value> module) {
+  if (id.empty() || module.IsEmpty())
+    return;
+
+  unsatisfied_dependencies_.erase(id);
+  available_modules_.insert(id);
+  Handle<Object> modules = Local<Object>::New(isolate, modules_);
+  modules->Set(StringToSymbol(isolate, id), module);
+}
 
-  if (!pending->id.empty() && modules->HasOwnProperty(key)) {
-    // We've already loaded a module with this name. Ignore the new one.
-    delete pending;
-    return true;
+void ModuleRegistry::Detach(Handle<Context> context) {
+  context->Global()->SetHiddenValue(GetHiddenValueKey(context->GetIsolate()),
+                                    Handle<Value>());
+}
+
+bool ModuleRegistry::CheckDependencies(PendingModule* pending) {
+  size_t num_missing_dependencies = 0;
+  size_t len = pending->dependencies.size();
+  for (size_t i = 0; i < len; ++i) {
+    const std::string& dependency = pending->dependencies[i];
+    if (available_modules_.count(dependency))
+      continue;
+    unsatisfied_dependencies_.insert(dependency);
+    num_missing_dependencies++;
   }
+  return num_missing_dependencies == 0;
+}
+
+void ModuleRegistry::Load(Isolate* isolate, scoped_ptr<PendingModule> pending) {
+  if (!pending->id.empty() && available_modules_.count(pending->id))
+    return;  // We've already loaded this module.
 
+  Handle<Object> modules = Local<Object>::New(isolate, modules_);
   size_t argc = pending->dependencies.size();
-  std::vector<Handle<v8::Value> > argv(argc);
+  std::vector<Handle<Value> > argv(argc);
   for (size_t i = 0; i < argc; ++i) {
-    Handle<v8::String> key = StringToV8(isolate, pending->dependencies[i]);
-    if (!modules->HasOwnProperty(key)) {
-      pending_modules_.push_back(pending);
-      return false;
-    }
+    Handle<String> key = StringToSymbol(isolate, pending->dependencies[i]);
+    DCHECK(modules->HasOwnProperty(key));
     argv[i] = modules->Get(key);
   }
 
-  Handle<v8::Value> module = v8::Local<v8::Value>::New(
-      isolate, pending->factory);
+  Handle<Value> module = Local<Value>::New(isolate, pending->factory);
 
-  Handle<v8::Function> factory;
+  Handle<Function> factory;
   if (ConvertFromV8(module, &factory)) {
-    v8::Handle<v8::Object> global = isolate->GetCurrentContext()->Global();
+    Handle<Object> global = isolate->GetCurrentContext()->Global();
     module = factory->Call(global, argc, argv.data());
     // TODO(abarth): What should we do with exceptions?
   }
 
-  if (!pending->id.empty() && !module.IsEmpty())
-    modules->Set(key, module);
+  RegisterModule(isolate, GetImplicitModuleName(pending->id), module);
+}
 
-  delete pending;
+bool ModuleRegistry::AttemptToLoad(Isolate* isolate,
+                                   scoped_ptr<PendingModule> pending) {
+  if (!CheckDependencies(pending.get())) {
+    pending_modules_.push_back(pending.release());
+    return false;
+  }
+  Load(isolate, pending.Pass());
   return true;
 }
 
-void ModuleRegistry::AttemptToLoadPendingModules(v8::Isolate* isolate) {
-  PendingModuleList pending_modules;
-  pending_modules.swap(pending_modules_);
-  for (PendingModuleList::iterator it = pending_modules.begin();
-       it != pending_modules.end(); ++it) {
-    AttemptToLoad(isolate, *it);
+void ModuleRegistry::AttemptToLoadMoreModules(Isolate* isolate) {
+  bool keep_trying = true;
+  while (keep_trying) {
+    keep_trying = false;
+    PendingModuleVector pending_modules;
+    pending_modules.swap(pending_modules_);
+    for (size_t i = 0; i < pending_modules.size(); ++i) {
+      scoped_ptr<PendingModule> pending(pending_modules[i]);
+      pending_modules[i] = NULL;
+      if (AttemptToLoad(isolate, pending.Pass()))
+        keep_trying = true;
+    }
   }
 }