Introduce ModulePendingScript

third_party/WebKit/Source/core/dom/ModulePendingScript.h

+#ifndef ModulePendingScript_h

[kouhei (in TOK), 2017/04/13 02:25:24]

missing the copyright 2017 comment

[hiroshige, 2017/04/13 17:53:56]

Done.

+#define ModulePendingScript_h
+
+#include "bindings/core/v8/TraceWrapperMember.h"
+#include "core/dom/Modulator.h"
+#include "core/dom/ModuleScript.h"
+#include "core/dom/PendingScript.h"
+
+namespace blink {
+
+class ModulePendingScript;
+
+// ModulePendingScriptTreeClient is used to connect from Modulator::FetchTree()
+// to ModulePendingScript. Because ModulePendingScript is created after
+// Modulator::FetchTree() is called, ModulePendingScriptTreeClient is
+// registered as ModuleTreeClient to FetchTree() first, and later
+// ModulePendingScript is supplied to ModulePendingScriptTreeClient via
+// SetPendingScript() and is notified of module tree load finish.
+class ModulePendingScriptTreeClient final
+    : public GarbageCollectedFinalized<ModulePendingScriptTreeClient>,
+      public TraceWrapperBase,

[kouhei (in TOK), 2017/04/13 02:25:24]

This doesn't have to be a TraceWrapperBase as discussed.
ModuleScript::m_instantiationError will be kept alive via
v8::Context->PerContextData->Modulator->ModuleMap->::Entry->ModuleScript->m_instantiationError.

[hiroshige, 2017/04/13 02:55:37]

So, we can avoid TraceWrapperMember<> and TraceWrapperBase everywhere, except
for the classes on the path above, particularly
- We can remove TraceWrapperBase and TraceWrapperMember<> in this file, and
- Also we can make Script non-TraceWrapperBase,
right?

I think we have to add a comment about how m_instantiationError is kept alive
somewhere.

[hiroshige, 2017/04/13 17:53:56]

Done.
Also created a separate CL for adding comments and making Script
non-TraceWrapperBase:
https://codereview.chromium.org/2820533003/

+      public ModuleTreeClient {
+  USING_GARBAGE_COLLECTED_MIXIN(ModulePendingScriptTreeClient);
+
+ public:
+  static ModulePendingScriptTreeClient* Create() {
+    return new ModulePendingScriptTreeClient();
+  }
+  virtual ~ModulePendingScriptTreeClient() = default;
+
+  void SetPendingScript(ModulePendingScript* client);
+
+  ModuleScript* GetModuleScript() const { return module_script_; }
+
+  DECLARE_TRACE();
+  DECLARE_TRACE_WRAPPERS();
+
+ private:
+  ModulePendingScriptTreeClient();
+
+  // Implements ModuleTreeClient
+  void NotifyModuleTreeLoadFinished(ModuleScript*) override;
+
+  bool finished_ = false;
+  TraceWrapperMember<ModuleScript> module_script_;
+  TraceWrapperMember<ModulePendingScript> pending_script_;

[kouhei (in TOK), 2017/04/13 02:25:24]

Ditto

[hiroshige, 2017/04/13 17:53:56]

Done.

+};
+
+class CORE_EXPORT ModulePendingScript : public PendingScript {
+ public:
+  static ModulePendingScript* Create(ScriptElementBase* element,
+                                     ModulePendingScriptTreeClient* client) {
+    return new ModulePendingScript(element, client);
+  }
+
+  ~ModulePendingScript() override;
+
+  void NotifyModuleTreeLoadFinished();
+
+  ModuleScript* GetModuleScript() const {
+    return module_tree_client_->GetModuleScript();
+  }
+
+  DECLARE_TRACE();
+  DECLARE_TRACE_WRAPPERS();

[kouhei (in TOK), 2017/04/13 02:25:24]

Ditto

[hiroshige, 2017/04/13 17:53:56]

Done.

+
+ private:
+  ModulePendingScript(ScriptElementBase*, ModulePendingScriptTreeClient*);
+
+  // PendingScript
+  ScriptType GetScriptType() const override { return ScriptType::kModule; }
+  Script* GetSource(const KURL& document_url,
+                    bool& error_occurred) const override;
+  bool IsReady() const override;
+  KURL Url() const override;
+  bool IsExternal() const override { return true; }
+  bool ErrorOccurred() const override;
+  bool WasCanceled() const override;
+  void StartStreamingIfPossible(Document*, ScriptStreamer::Type) override;
+  void DisposeInternal() override;
+  void RemoveFromMemoryCache() override { NOTREACHED(); }
+
+  // FOXME: state check?
+  void CheckState() const override {}
+
+  TraceWrapperMember<ModulePendingScriptTreeClient> module_tree_client_;
+  bool finished_ = false;
+};
+
+}  // namespace blink
+
+#endif  // ModulePendingScript_h