gecko-dev/xpcom/glue/nsHashKeys.h
Nicholas Nethercote ddc78c3b0c Bug 1229458 - Remove SizeOfIncludingThisMustBeUnshared() from string classes. r=mccr8.
The patch changes all uses of SizeOfIncludingThisMustBeUnshared() to
SizeOfIncludingThisIfUnshared(). This incurs the (tiny) cost of an unnecessary
IsReadonly() check for guaranteed-unshared strings, but avoids the possible
assertion failures that would occur when MustBeUnshared() was used incorrectly
on shared strings, which is an easy mistake to make.

--HG--
extra : rebase_source : b1e91f1c19bcbe0521b0ce461d6c90512ca938ef
2015-12-01 15:36:26 -08:00

691 lines
17 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/. */
#ifndef nsTHashKeys_h__
#define nsTHashKeys_h__
#include "nsID.h"
#include "nsISupports.h"
#include "nsIHashable.h"
#include "nsAutoPtr.h"
#include "nsCOMPtr.h"
#include "PLDHashTable.h"
#include <new>
#include "nsStringGlue.h"
#include "nsCRTGlue.h"
#include "nsUnicharUtils.h"
#include <stdlib.h>
#include <string.h>
#include "mozilla/HashFunctions.h"
#include "mozilla/Move.h"
namespace mozilla {
// These are defined analogously to the HashString overloads in mfbt.
inline uint32_t
HashString(const nsAString& aStr)
{
return HashString(aStr.BeginReading(), aStr.Length());
}
inline uint32_t
HashString(const nsACString& aStr)
{
return HashString(aStr.BeginReading(), aStr.Length());
}
} // namespace mozilla
/** @file nsHashKeys.h
* standard HashKey classes for nsBaseHashtable and relatives. Each of these
* classes follows the nsTHashtable::EntryType specification
*
* Lightweight keytypes provided here:
* nsStringHashKey
* nsCStringHashKey
* nsUint32HashKey
* nsUint64HashKey
* nsFloatHashKey
* nsPtrHashKey
* nsClearingPtrHashKey
* nsVoidPtrHashKey
* nsClearingVoidPtrHashKey
* nsISupportsHashKey
* nsIDHashKey
* nsDepCharHashKey
* nsCharPtrHashKey
* nsUnicharPtrHashKey
* nsHashableHashKey
* nsGenericHashKey
*/
/**
* hashkey wrapper using nsAString KeyType
*
* @see nsTHashtable::EntryType for specification
*/
class nsStringHashKey : public PLDHashEntryHdr
{
public:
typedef const nsAString& KeyType;
typedef const nsAString* KeyTypePointer;
explicit nsStringHashKey(KeyTypePointer aStr) : mStr(*aStr) {}
nsStringHashKey(const nsStringHashKey& aToCopy) : mStr(aToCopy.mStr) {}
~nsStringHashKey() {}
KeyType GetKey() const { return mStr; }
bool KeyEquals(const KeyTypePointer aKey) const
{
return mStr.Equals(*aKey);
}
static KeyTypePointer KeyToPointer(KeyType aKey) { return &aKey; }
static PLDHashNumber HashKey(const KeyTypePointer aKey)
{
return mozilla::HashString(*aKey);
}
#ifdef MOZILLA_INTERNAL_API
// To avoid double-counting, only measure the string if it is unshared.
size_t SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const
{
return GetKey().SizeOfExcludingThisIfUnshared(aMallocSizeOf);
}
#endif
enum { ALLOW_MEMMOVE = true };
private:
const nsString mStr;
};
#ifdef MOZILLA_INTERNAL_API
/**
* hashkey wrapper using nsAString KeyType
*
* This is internal-API only because nsCaseInsensitiveStringComparator is
* internal-only.
*
* @see nsTHashtable::EntryType for specification
*/
class nsStringCaseInsensitiveHashKey : public PLDHashEntryHdr
{
public:
typedef const nsAString& KeyType;
typedef const nsAString* KeyTypePointer;
explicit nsStringCaseInsensitiveHashKey(KeyTypePointer aStr)
: mStr(*aStr)
{
// take it easy just deal HashKey
}
nsStringCaseInsensitiveHashKey(const nsStringCaseInsensitiveHashKey& aToCopy)
: mStr(aToCopy.mStr)
{
}
~nsStringCaseInsensitiveHashKey() {}
KeyType GetKey() const { return mStr; }
bool KeyEquals(const KeyTypePointer aKey) const
{
return mStr.Equals(*aKey, nsCaseInsensitiveStringComparator());
}
static KeyTypePointer KeyToPointer(KeyType aKey) { return &aKey; }
static PLDHashNumber HashKey(const KeyTypePointer aKey)
{
nsAutoString tmKey(*aKey);
ToLowerCase(tmKey);
return mozilla::HashString(tmKey);
}
enum { ALLOW_MEMMOVE = true };
// To avoid double-counting, only measure the string if it is unshared.
size_t SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const
{
return GetKey().SizeOfExcludingThisIfUnshared(aMallocSizeOf);
}
private:
const nsString mStr;
};
#endif
/**
* hashkey wrapper using nsACString KeyType
*
* @see nsTHashtable::EntryType for specification
*/
class nsCStringHashKey : public PLDHashEntryHdr
{
public:
typedef const nsACString& KeyType;
typedef const nsACString* KeyTypePointer;
explicit nsCStringHashKey(const nsACString* aStr) : mStr(*aStr) {}
nsCStringHashKey(const nsCStringHashKey& aToCopy) : mStr(aToCopy.mStr) {}
~nsCStringHashKey() {}
KeyType GetKey() const { return mStr; }
bool KeyEquals(KeyTypePointer aKey) const { return mStr.Equals(*aKey); }
static KeyTypePointer KeyToPointer(KeyType aKey) { return &aKey; }
static PLDHashNumber HashKey(KeyTypePointer aKey)
{
return mozilla::HashString(*aKey);
}
#ifdef MOZILLA_INTERNAL_API
// To avoid double-counting, only measure the string if it is unshared.
size_t SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const
{
return GetKey().SizeOfExcludingThisIfUnshared(aMallocSizeOf);
}
#endif
enum { ALLOW_MEMMOVE = true };
private:
const nsCString mStr;
};
/**
* hashkey wrapper using uint32_t KeyType
*
* @see nsTHashtable::EntryType for specification
*/
class nsUint32HashKey : public PLDHashEntryHdr
{
public:
typedef const uint32_t& KeyType;
typedef const uint32_t* KeyTypePointer;
explicit nsUint32HashKey(KeyTypePointer aKey) : mValue(*aKey) {}
nsUint32HashKey(const nsUint32HashKey& aToCopy) : mValue(aToCopy.mValue) {}
~nsUint32HashKey() {}
KeyType GetKey() const { return mValue; }
bool KeyEquals(KeyTypePointer aKey) const { return *aKey == mValue; }
static KeyTypePointer KeyToPointer(KeyType aKey) { return &aKey; }
static PLDHashNumber HashKey(KeyTypePointer aKey) { return *aKey; }
enum { ALLOW_MEMMOVE = true };
private:
const uint32_t mValue;
};
/**
* hashkey wrapper using uint64_t KeyType
*
* @see nsTHashtable::EntryType for specification
*/
class nsUint64HashKey : public PLDHashEntryHdr
{
public:
typedef const uint64_t& KeyType;
typedef const uint64_t* KeyTypePointer;
explicit nsUint64HashKey(KeyTypePointer aKey) : mValue(*aKey) {}
nsUint64HashKey(const nsUint64HashKey& aToCopy) : mValue(aToCopy.mValue) {}
~nsUint64HashKey() {}
KeyType GetKey() const { return mValue; }
bool KeyEquals(KeyTypePointer aKey) const { return *aKey == mValue; }
static KeyTypePointer KeyToPointer(KeyType aKey) { return &aKey; }
static PLDHashNumber HashKey(KeyTypePointer aKey)
{
return PLDHashNumber(*aKey);
}
enum { ALLOW_MEMMOVE = true };
private:
const uint64_t mValue;
};
/**
* hashkey wrapper using float KeyType
*
* @see nsTHashtable::EntryType for specification
*/
class nsFloatHashKey : public PLDHashEntryHdr
{
public:
typedef const float& KeyType;
typedef const float* KeyTypePointer;
explicit nsFloatHashKey(KeyTypePointer aKey) : mValue(*aKey) {}
nsFloatHashKey(const nsFloatHashKey& aToCopy) : mValue(aToCopy.mValue) {}
~nsFloatHashKey() {}
KeyType GetKey() const { return mValue; }
bool KeyEquals(KeyTypePointer aKey) const { return *aKey == mValue; }
static KeyTypePointer KeyToPointer(KeyType aKey) { return &aKey; }
static PLDHashNumber HashKey(KeyTypePointer aKey)
{
return *reinterpret_cast<const uint32_t*>(aKey);
}
enum { ALLOW_MEMMOVE = true };
private:
const float mValue;
};
/**
* hashkey wrapper using nsISupports* KeyType
*
* @see nsTHashtable::EntryType for specification
*/
class nsISupportsHashKey : public PLDHashEntryHdr
{
public:
typedef nsISupports* KeyType;
typedef const nsISupports* KeyTypePointer;
explicit nsISupportsHashKey(const nsISupports* aKey)
: mSupports(const_cast<nsISupports*>(aKey))
{
}
nsISupportsHashKey(const nsISupportsHashKey& aToCopy)
: mSupports(aToCopy.mSupports)
{
}
~nsISupportsHashKey() {}
KeyType GetKey() const { return mSupports; }
bool KeyEquals(KeyTypePointer aKey) const { return aKey == mSupports; }
static KeyTypePointer KeyToPointer(KeyType aKey) { return aKey; }
static PLDHashNumber HashKey(KeyTypePointer aKey)
{
return NS_PTR_TO_UINT32(aKey) >> 2;
}
enum { ALLOW_MEMMOVE = true };
private:
nsCOMPtr<nsISupports> mSupports;
};
/**
* hashkey wrapper using refcounted * KeyType
*
* @see nsTHashtable::EntryType for specification
*/
template<class T>
class nsRefPtrHashKey : public PLDHashEntryHdr
{
public:
typedef T* KeyType;
typedef const T* KeyTypePointer;
explicit nsRefPtrHashKey(const T* aKey) : mKey(const_cast<T*>(aKey)) {}
nsRefPtrHashKey(const nsRefPtrHashKey& aToCopy) : mKey(aToCopy.mKey) {}
~nsRefPtrHashKey() {}
KeyType GetKey() const { return mKey; }
bool KeyEquals(KeyTypePointer aKey) const { return aKey == mKey; }
static KeyTypePointer KeyToPointer(KeyType aKey) { return aKey; }
static PLDHashNumber HashKey(KeyTypePointer aKey)
{
return NS_PTR_TO_UINT32(aKey) >> 2;
}
enum { ALLOW_MEMMOVE = true };
private:
RefPtr<T> mKey;
};
template<class T>
inline void
ImplCycleCollectionTraverse(nsCycleCollectionTraversalCallback& aCallback,
nsRefPtrHashKey<T>& aField,
const char* aName,
uint32_t aFlags = 0)
{
CycleCollectionNoteChild(aCallback, aField.GetKey(), aName, aFlags);
}
/**
* hashkey wrapper using T* KeyType
*
* @see nsTHashtable::EntryType for specification
*/
template<class T>
class nsPtrHashKey : public PLDHashEntryHdr
{
public:
typedef T* KeyType;
typedef const T* KeyTypePointer;
explicit nsPtrHashKey(const T* aKey) : mKey(const_cast<T*>(aKey)) {}
nsPtrHashKey(const nsPtrHashKey<T>& aToCopy) : mKey(aToCopy.mKey) {}
~nsPtrHashKey() {}
KeyType GetKey() const { return mKey; }
bool KeyEquals(KeyTypePointer aKey) const { return aKey == mKey; }
static KeyTypePointer KeyToPointer(KeyType aKey) { return aKey; }
static PLDHashNumber HashKey(KeyTypePointer aKey)
{
return NS_PTR_TO_UINT32(aKey) >> 2;
}
enum { ALLOW_MEMMOVE = true };
protected:
T* MOZ_NON_OWNING_REF mKey;
};
/**
* hashkey wrapper using T* KeyType that sets key to nullptr upon
* destruction. Relevant only in cases where a memory pointer-scanner
* like valgrind might get confused about stale references.
*
* @see nsTHashtable::EntryType for specification
*/
template<class T>
class nsClearingPtrHashKey : public nsPtrHashKey<T>
{
public:
explicit nsClearingPtrHashKey(const T* aKey) : nsPtrHashKey<T>(aKey) {}
nsClearingPtrHashKey(const nsClearingPtrHashKey<T>& aToCopy)
: nsPtrHashKey<T>(aToCopy)
{
}
~nsClearingPtrHashKey() { nsPtrHashKey<T>::mKey = nullptr; }
};
typedef nsPtrHashKey<const void> nsVoidPtrHashKey;
typedef nsClearingPtrHashKey<const void> nsClearingVoidPtrHashKey;
/**
* hashkey wrapper using a function pointer KeyType
*
* @see nsTHashtable::EntryType for specification
*/
template<class T>
class nsFuncPtrHashKey : public PLDHashEntryHdr
{
public:
typedef T& KeyType;
typedef const T* KeyTypePointer;
explicit nsFuncPtrHashKey(const T* aKey) : mKey(*const_cast<T*>(aKey)) {}
nsFuncPtrHashKey(const nsFuncPtrHashKey<T>& aToCopy) : mKey(aToCopy.mKey) {}
~nsFuncPtrHashKey() {}
KeyType GetKey() const { return const_cast<T&>(mKey); }
bool KeyEquals(KeyTypePointer aKey) const { return *aKey == mKey; }
static KeyTypePointer KeyToPointer(KeyType aKey) { return &aKey; }
static PLDHashNumber HashKey(KeyTypePointer aKey)
{
return NS_PTR_TO_UINT32(*aKey) >> 2;
}
enum { ALLOW_MEMMOVE = true };
protected:
T mKey;
};
/**
* hashkey wrapper using nsID KeyType
*
* @see nsTHashtable::EntryType for specification
*/
class nsIDHashKey : public PLDHashEntryHdr
{
public:
typedef const nsID& KeyType;
typedef const nsID* KeyTypePointer;
explicit nsIDHashKey(const nsID* aInID) : mID(*aInID) {}
nsIDHashKey(const nsIDHashKey& aToCopy) : mID(aToCopy.mID) {}
~nsIDHashKey() {}
KeyType GetKey() const { return mID; }
bool KeyEquals(KeyTypePointer aKey) const { return aKey->Equals(mID); }
static KeyTypePointer KeyToPointer(KeyType aKey) { return &aKey; }
static PLDHashNumber HashKey(KeyTypePointer aKey)
{
// Hash the nsID object's raw bytes.
return mozilla::HashBytes(aKey, sizeof(KeyType));
}
enum { ALLOW_MEMMOVE = true };
private:
const nsID mID;
};
/**
* hashkey wrapper for "dependent" const char*; this class does not "own"
* its string pointer.
*
* This class must only be used if the strings have a lifetime longer than
* the hashtable they occupy. This normally occurs only for static
* strings or strings that have been arena-allocated.
*
* @see nsTHashtable::EntryType for specification
*/
class nsDepCharHashKey : public PLDHashEntryHdr
{
public:
typedef const char* KeyType;
typedef const char* KeyTypePointer;
explicit nsDepCharHashKey(const char* aKey) : mKey(aKey) {}
nsDepCharHashKey(const nsDepCharHashKey& aToCopy) : mKey(aToCopy.mKey) {}
~nsDepCharHashKey() {}
const char* GetKey() const { return mKey; }
bool KeyEquals(const char* aKey) const { return !strcmp(mKey, aKey); }
static const char* KeyToPointer(const char* aKey) { return aKey; }
static PLDHashNumber HashKey(const char* aKey)
{
return mozilla::HashString(aKey);
}
enum { ALLOW_MEMMOVE = true };
private:
const char* mKey;
};
/**
* hashkey wrapper for const char*; at construction, this class duplicates
* a string pointed to by the pointer so that it doesn't matter whether or not
* the string lives longer than the hash table.
*/
class nsCharPtrHashKey : public PLDHashEntryHdr
{
public:
typedef const char* KeyType;
typedef const char* KeyTypePointer;
explicit nsCharPtrHashKey(const char* aKey) : mKey(strdup(aKey)) {}
nsCharPtrHashKey(const nsCharPtrHashKey& aToCopy)
: mKey(strdup(aToCopy.mKey))
{
}
nsCharPtrHashKey(nsCharPtrHashKey&& aOther)
: mKey(aOther.mKey)
{
aOther.mKey = nullptr;
}
~nsCharPtrHashKey()
{
if (mKey) {
free(const_cast<char*>(mKey));
}
}
const char* GetKey() const { return mKey; }
bool KeyEquals(KeyTypePointer aKey) const { return !strcmp(mKey, aKey); }
static KeyTypePointer KeyToPointer(KeyType aKey) { return aKey; }
static PLDHashNumber HashKey(KeyTypePointer aKey)
{
return mozilla::HashString(aKey);
}
size_t SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const
{
return aMallocSizeOf(mKey);
}
enum { ALLOW_MEMMOVE = true };
private:
const char* mKey;
};
/**
* hashkey wrapper for const char16_t*; at construction, this class duplicates
* a string pointed to by the pointer so that it doesn't matter whether or not
* the string lives longer than the hash table.
*/
class nsUnicharPtrHashKey : public PLDHashEntryHdr
{
public:
typedef const char16_t* KeyType;
typedef const char16_t* KeyTypePointer;
explicit nsUnicharPtrHashKey(const char16_t* aKey) : mKey(NS_strdup(aKey)) {}
nsUnicharPtrHashKey(const nsUnicharPtrHashKey& aToCopy)
: mKey(NS_strdup(aToCopy.mKey))
{
}
nsUnicharPtrHashKey(nsUnicharPtrHashKey&& aOther)
: mKey(aOther.mKey)
{
aOther.mKey = nullptr;
}
~nsUnicharPtrHashKey()
{
if (mKey) {
NS_Free(const_cast<char16_t*>(mKey));
}
}
const char16_t* GetKey() const { return mKey; }
bool KeyEquals(KeyTypePointer aKey) const { return !NS_strcmp(mKey, aKey); }
static KeyTypePointer KeyToPointer(KeyType aKey) { return aKey; }
static PLDHashNumber HashKey(KeyTypePointer aKey)
{
return mozilla::HashString(aKey);
}
size_t SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const
{
return aMallocSizeOf(mKey);
}
enum { ALLOW_MEMMOVE = true };
private:
const char16_t* mKey;
};
/**
* Hashtable key class to use with objects that support nsIHashable
*/
class nsHashableHashKey : public PLDHashEntryHdr
{
public:
typedef nsIHashable* KeyType;
typedef const nsIHashable* KeyTypePointer;
explicit nsHashableHashKey(const nsIHashable* aKey)
: mKey(const_cast<nsIHashable*>(aKey))
{
}
nsHashableHashKey(const nsHashableHashKey& aToCopy) : mKey(aToCopy.mKey) {}
~nsHashableHashKey() {}
nsIHashable* GetKey() const { return mKey; }
bool KeyEquals(const nsIHashable* aKey) const
{
bool eq;
if (NS_SUCCEEDED(mKey->Equals(const_cast<nsIHashable*>(aKey), &eq))) {
return eq;
}
return false;
}
static const nsIHashable* KeyToPointer(nsIHashable* aKey) { return aKey; }
static PLDHashNumber HashKey(const nsIHashable* aKey)
{
uint32_t code = 8888; // magic number if GetHashCode fails :-(
#ifdef DEBUG
nsresult rv =
#endif
const_cast<nsIHashable*>(aKey)->GetHashCode(&code);
NS_ASSERTION(NS_SUCCEEDED(rv), "GetHashCode should not throw!");
return code;
}
enum { ALLOW_MEMMOVE = true };
private:
nsCOMPtr<nsIHashable> mKey;
};
namespace mozilla {
template <typename T>
PLDHashNumber
Hash(const T& aValue)
{
return aValue.Hash();
}
} // namespace mozilla
/**
* Hashtable key class to use with objects for which Hash() and operator==()
* are defined.
*/
template<typename T>
class nsGenericHashKey : public PLDHashEntryHdr
{
public:
typedef const T& KeyType;
typedef const T* KeyTypePointer;
explicit nsGenericHashKey(KeyTypePointer aKey) : mKey(*aKey) {}
nsGenericHashKey(const nsGenericHashKey<T>& aOther) : mKey(aOther.mKey) {}
KeyType GetKey() const { return mKey; }
bool KeyEquals(KeyTypePointer aKey) const { return *aKey == mKey; }
static KeyTypePointer KeyToPointer(KeyType aKey) { return &aKey; }
static PLDHashNumber HashKey(KeyTypePointer aKey) { return ::mozilla::Hash(*aKey); }
enum { ALLOW_MEMMOVE = true };
private:
T mKey;
};
#endif // nsTHashKeys_h__