// Copyright 2017 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef THIRD_PARTY_BLINK_RENDERER_CORE_SCRIPT_CLASSIC_PENDING_SCRIPT_H_
#define THIRD_PARTY_BLINK_RENDERER_CORE_SCRIPT_CLASSIC_PENDING_SCRIPT_H_

#include "third_party/blink/renderer/bindings/core/v8/script_cache_consumer_client.h"
#include "third_party/blink/renderer/bindings/core/v8/script_source_location_type.h"
#include "third_party/blink/renderer/bindings/core/v8/script_streamer.h"
#include "third_party/blink/renderer/core/core_export.h"
#include "third_party/blink/renderer/core/loader/resource/script_resource.h"
#include "third_party/blink/renderer/core/script/cache_hint_attribute_value.h"
#include "third_party/blink/renderer/core/script/classic_script.h"
#include "third_party/blink/renderer/core/script/pending_script.h"
#include "third_party/blink/renderer/platform/instrumentation/memory_pressure_listener.h"
#include "third_party/blink/renderer/platform/loader/fetch/fetch_parameters.h"

namespace blink {

// PendingScript for a classic script
// https://html.spec.whatwg.org/C/#classic-script.
//
// TODO(kochi): The comment below is from pre-oilpan age and may not be correct
// now.
// A RefPtr alone does not prevent the underlying Resource from purging its data
// buffer. This class holds a dummy client open for its lifetime in order to
// guarantee that the data buffer will not be purged.
class CORE_EXPORT ClassicPendingScript final
    : public PendingScript,
      public ResourceClient,
      public ScriptCacheConsumerClient {
 public:
  // https://html.spec.whatwg.org/C/#fetch-a-classic-script
  //
  // For a script from an external file, calls ScriptResource::Fetch() and
  // creates ClassicPendingScript. Returns nullptr if Fetch() returns nullptr.
  static ClassicPendingScript* Fetch(
      const KURL&,
      Document&,
      const ScriptFetchOptions&,
      CrossOriginAttributeValue,
      const TextEncoding&,
      ScriptElementBase*,
      FetchParameters::DeferOption,
      scheduler::TaskAttributionInfo* task_state);

  // For an inline script.
  static ClassicPendingScript* CreateInline(ScriptElementBase*,
                                            const TextPosition&,
                                            const KURL& source_url,
                                            const KURL& base_url,
                                            const String& source_text,
                                            ScriptSourceLocationType,
                                            const ScriptFetchOptions&,
                                            scheduler::TaskAttributionInfo*,
                                            CacheHintAttributeValue);

  ClassicPendingScript(ScriptElementBase*,
                       const TextPosition&,
                       const KURL& source_url_for_inline_script,
                       const KURL& base_url_for_inline_script,
                       const String& source_text_for_inline_script,
                       ScriptSourceLocationType,
                       const ScriptFetchOptions&,
                       bool is_external,
                       scheduler::TaskAttributionInfo* task_state,
                       CacheHintAttributeValue cache_hint);
  ~ClassicPendingScript() override;

  void Trace(Visitor*) const override;

  mojom::blink::ScriptType GetScriptType() const override {
    return mojom::blink::ScriptType::kClassic;
  }

  ClassicScript* GetSource() const override;
  bool IsReady() const override;
  bool IsExternal() const override { return is_external_; }
  bool WasCanceled() const override;
  KURL UrlForTracing() const override;
  void DisposeInternal() override;

  // ScriptCacheConsumerClient:
  void NotifyCacheConsumeFinished() override;

  // Check if this script is eligible for kLowPriorityAsyncScriptExecution
  // feature (see crbug/1348467).
  bool IsEligibleForLowPriorityAsyncScriptExecution() const override;

 private:
  // See AdvanceReadyState implementation for valid state transitions.
  enum ReadyState : uint8_t {
    // These states are considered "not ready".
    kWaitingForResource,
    kWaitingForCacheConsumer,
    // These states are considered "ready".
    kReady,
    kErrorOccurred,
  };

  ClassicPendingScript() = delete;

  static bool StateIsReady(ReadyState);

  // Advances the current state of the script, reporting to the client if
  // appropriate.
  void AdvanceReadyState(ReadyState);

  void CheckState() const override;

  // ResourceClient
  void NotifyFinished(Resource*) override;
  String DebugName() const override { return "PendingScript"; }

  void RecordThirdPartyRequestWithCookieIfNeeded(const ResourceResponse&) const;

  const ScriptFetchOptions options_;

  const KURL source_url_for_inline_script_;

  // "base url" snapshot taken at #prepare-a-script timing.
  // https://html.spec.whatwg.org/C/#prepare-a-script
  // which will eventually be used as #concept-script-base-url.
  // https://html.spec.whatwg.org/C/#concept-script-base-url
  // This is a null URL for external scripts and is not used.
  const KURL base_url_for_inline_script_;

  // "element's child text content" snapshot taken at
  // #prepare-a-script (Step 4).
  // This is a null string for external scripts and is not used.
  const String source_text_for_inline_script_;

  Member<ClassicScript> classic_script_;

  const ScriptSourceLocationType source_location_type_;
  const bool is_external_;
  ReadyState ready_state_;
  const CacheHintAttributeValue cache_hint_;

  // The request is intervened by document.write() intervention.
  bool intervened_ = false;
};

}  // namespace blink

#endif  // THIRD_PARTY_BLINK_RENDERER_CORE_SCRIPT_CLASSIC_PENDING_SCRIPT_H_