text: /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
  /* vim: set ts=8 sts=2 et sw=2 tw=80: */
  /* This Source Code Form is subject to the terms of the Mozilla Public
   * License, v. 2.0. If a copy of the MPL was not distributed with this
   * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
  
  /**
   * Class for representing MozMap arguments.  This is an nsTHashtable
   * under the hood, but we don't want to leak that implementation
   * detail.
   */
  
  #ifndef mozilla_dom_MozMap_h
  #define mozilla_dom_MozMap_h
  
  #include "nsTHashtable.h"
  #include "nsHashKeys.h"
  #include "nsStringGlue.h"
  #include "nsTArray.h"
  #include "mozilla/Attributes.h"
  #include "mozilla/Move.h"
  
  namespace mozilla {
  namespace dom {
  
  namespace binding_detail {
  template<typename DataType>
  class MozMapEntry : public nsStringHashKey
  {
  public:
    explicit MozMapEntry(const nsAString* aKeyTypePointer)
      : nsStringHashKey(aKeyTypePointer)
    {
    }
  
    // Move constructor so we can do MozMaps of MozMaps.
    MozMapEntry(MozMapEntry<DataType>&& aOther)
      : nsStringHashKey(aOther),
        mData(Move(aOther.mData))
    {
    }
  
    DataType mData;
  };
  } // namespace binding_detail
  
  template<typename DataType>
  class MozMap : protected nsTHashtable<binding_detail::MozMapEntry<DataType>>
  {
  public:
    typedef typename binding_detail::MozMapEntry<DataType> EntryType;
    typedef nsTHashtable<EntryType> Base;
    typedef MozMap<DataType> SelfType;
  
    MozMap()
    {
    }
  
    // Move constructor so we can do MozMap of MozMap.
    MozMap(SelfType&& aOther) :
      Base(Move(aOther))
    {
    }
  
    // The return value is only safe to use until an AddEntry call.
    const DataType& Get(const nsAString& aKey) const
    {
      const EntryType* ent = this->GetEntry(aKey);
      MOZ_ASSERT(ent, "Why are you using a key we didn't claim to have?");
      return ent->mData;
    }
  
    DataType& Get(const nsAString& aKey)
    {
      EntryType* ent = this->GetEntry(aKey);
      MOZ_ASSERT(ent, "Why are you using a key we didn't claim to have?");
      return ent->mData;
    }
  
    // The return value is only safe to use until an AddEntry call.
    const DataType* GetIfExists(const nsAString& aKey) const
    {
      const EntryType* ent = this->GetEntry(aKey);
      if (!ent) {
        return nullptr;
      }
      return &ent->mData;
    }
  
    void GetKeys(nsTArray<nsString>& aKeys) const {
      // Sadly, EnumerateEntries is not a const method
      const_cast<SelfType*>(this)->EnumerateEntries(KeyEnumerator, &aKeys);
    }
  
    // XXXbz we expose this generic enumerator for tracing.  Otherwise we'd end up
    // with a dependency on BindingUtils.h here for the SequenceTracer bits.
    typedef PLDHashOperator (* Enumerator)(DataType* aValue, void* aClosure);
    void EnumerateValues(Enumerator aEnumerator, void *aClosure)
    {
      ValueEnumClosure args = { aEnumerator, aClosure };
      this->EnumerateEntries(ValueEnumerator, &args);
    }
  
    MOZ_WARN_UNUSED_RESULT
    DataType* AddEntry(const nsAString& aKey)
    {
      EntryType* ent = this->PutEntry(aKey, fallible);
      if (!ent) {
        return nullptr;
      }
      return &ent->mData;
    }
  
  private:
    static PLDHashOperator
    KeyEnumerator(EntryType* aEntry, void* aClosure)
    {
      nsTArray<nsString>& keys = *static_cast<nsTArray<nsString>*>(aClosure);
      keys.AppendElement(aEntry->GetKey());
      return PL_DHASH_NEXT;
    }
  
    struct ValueEnumClosure {
      Enumerator mEnumerator;
      void* mClosure;
    };
  
    static PLDHashOperator
    ValueEnumerator(EntryType* aEntry, void* aClosure)
    {
      ValueEnumClosure* enumClosure = static_cast<ValueEnumClosure*>(aClosure);
      return enumClosure->mEnumerator(&aEntry->mData, enumClosure->mClosure);
    }
  };
  
  } // namespace dom
  } // namespace mozilla
  
  #endif // mozilla_dom_MozMap_h
  