gecko-dev/dom/bindings/MozMap.h

140 lines
3.7 KiB
C++

/* -*- 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/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);
}
DataType* AddEntry(const nsAString& aKey) NS_WARN_UNUSED_RESULT
{
// XXXbz can't just use fallible_t() because our superclass has a
// private typedef by that name.
EntryType* ent = this->PutEntry(aKey, mozilla::fallible_t());
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