mirror of
https://github.com/mozilla/gecko-dev.git
synced 2024-10-23 18:26:15 +00:00
e7b3b3140d
Everything that goes in a PLDHashtable (and its derivatives, like nsTHashtable) needs to inherit from PLDHashEntryHdr. But through a lack of enforcement, copy constructors for these derived classes didn't explicitly invoke the copy constructor for PLDHashEntryHdr (and the compiler didn't invoke the copy constructor for us). Instead, PLDHashTable explicitly copied around the bits that the copy constructor would have. The current setup has two problems: 1) Derived classes should be using move construction, not copy construction, since anything that's shuffling hash table keys/entries around will be using move construction. 2) Derived classes should take responsibility for transferring bits of superclass state around, and not rely on something else to handle that. The second point is not a huge problem for PLDHashTable (PLDHashTable only has to copy PLDHashEntryHdr's bits in a single place), but future hash table implementations that might move entries around more aggressively would have to insert compensation code all over the place. Additionally, if moving entries is implemented via memcpy (which is quite common), PLDHashTable copying around bits *again* is inefficient. Let's fix all these problems in one go, by: 1) Explicitly declaring the set of constructors that PLDHashEntryHdr implements (and does not implement). In particular, the copy constructor is deleted, so any derived classes that attempt to make themselves copyable will be detected at compile time: the compiler will complain that the superclass type is not copyable. This change on its own will result in many compiler errors, so... 2) Change any derived classes to implement move constructors instead of copy constructors. Note that some of these move constructors are, strictly speaking, unnecessary, since the relevant classes are moved via memcpy in nsTHashtable and its derivatives.
137 lines
4.3 KiB
C++
137 lines
4.3 KiB
C++
/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
|
|
|
|
/* 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 GFX_FONT_FEATURES_H
|
|
#define GFX_FONT_FEATURES_H
|
|
|
|
#include "nsTHashtable.h"
|
|
#include "nsTArray.h"
|
|
#include "nsString.h"
|
|
|
|
// An OpenType feature tag and value pair
|
|
struct gfxFontFeature {
|
|
uint32_t mTag; // see http://www.microsoft.com/typography/otspec/featuretags.htm
|
|
uint32_t mValue; // 0 = off, 1 = on, larger values may be used as parameters
|
|
// to features that select among multiple alternatives
|
|
};
|
|
|
|
inline bool
|
|
operator<(const gfxFontFeature& a, const gfxFontFeature& b)
|
|
{
|
|
return (a.mTag < b.mTag) || ((a.mTag == b.mTag) && (a.mValue < b.mValue));
|
|
}
|
|
|
|
inline bool
|
|
operator==(const gfxFontFeature& a, const gfxFontFeature& b)
|
|
{
|
|
return (a.mTag == b.mTag) && (a.mValue == b.mValue);
|
|
}
|
|
|
|
struct gfxAlternateValue {
|
|
uint32_t alternate; // constants in gfxFontConstants.h
|
|
nsString value; // string value to be looked up
|
|
};
|
|
|
|
inline bool
|
|
operator<(const gfxAlternateValue& a, const gfxAlternateValue& b)
|
|
{
|
|
return (a.alternate < b.alternate) ||
|
|
((a.alternate == b.alternate) && (a.value < b.value));
|
|
}
|
|
|
|
inline bool
|
|
operator==(const gfxAlternateValue& a, const gfxAlternateValue& b)
|
|
{
|
|
return (a.alternate == b.alternate) && (a.value == b.value);
|
|
}
|
|
|
|
class gfxFontFeatureValueSet final {
|
|
public:
|
|
NS_INLINE_DECL_THREADSAFE_REFCOUNTING(gfxFontFeatureValueSet)
|
|
|
|
gfxFontFeatureValueSet();
|
|
|
|
struct ValueList {
|
|
ValueList(const nsAString& aName, const nsTArray<uint32_t>& aSelectors)
|
|
: name(aName), featureSelectors(aSelectors)
|
|
{}
|
|
nsString name;
|
|
nsTArray<uint32_t> featureSelectors;
|
|
};
|
|
|
|
struct FeatureValues {
|
|
uint32_t alternate;
|
|
nsTArray<ValueList> valuelist;
|
|
};
|
|
|
|
// returns true if found, false otherwise
|
|
bool
|
|
GetFontFeatureValuesFor(const nsACString& aFamily,
|
|
uint32_t aVariantProperty,
|
|
const nsAString& aName,
|
|
nsTArray<uint32_t>& aValues);
|
|
void
|
|
AddFontFeatureValues(const nsACString& aFamily,
|
|
const nsTArray<gfxFontFeatureValueSet::FeatureValues>& aValues);
|
|
|
|
// Appends a new hash entry with given key values and returns a pointer to
|
|
// mValues array to fill. This should be filled first.
|
|
nsTArray<uint32_t>*
|
|
AppendFeatureValueHashEntry(const nsACString& aFamily,
|
|
const nsAString& aName,
|
|
uint32_t aAlternate);
|
|
|
|
private:
|
|
// Private destructor, to discourage deletion outside of Release():
|
|
~gfxFontFeatureValueSet() {}
|
|
|
|
struct FeatureValueHashKey {
|
|
nsCString mFamily;
|
|
uint32_t mPropVal;
|
|
nsString mName;
|
|
|
|
FeatureValueHashKey()
|
|
: mPropVal(0)
|
|
{ }
|
|
FeatureValueHashKey(const nsACString& aFamily,
|
|
uint32_t aPropVal,
|
|
const nsAString& aName)
|
|
: mFamily(aFamily), mPropVal(aPropVal), mName(aName)
|
|
{ }
|
|
FeatureValueHashKey(const FeatureValueHashKey& aKey)
|
|
: mFamily(aKey.mFamily), mPropVal(aKey.mPropVal), mName(aKey.mName)
|
|
{ }
|
|
};
|
|
|
|
class FeatureValueHashEntry : public PLDHashEntryHdr {
|
|
public:
|
|
typedef const FeatureValueHashKey &KeyType;
|
|
typedef const FeatureValueHashKey *KeyTypePointer;
|
|
|
|
explicit FeatureValueHashEntry(KeyTypePointer aKey) { }
|
|
FeatureValueHashEntry(FeatureValueHashEntry&& other)
|
|
: PLDHashEntryHdr(std::move(other))
|
|
, mKey(std::move(other.mKey))
|
|
, mValues(std::move(other.mValues))
|
|
{
|
|
NS_ERROR("Should not be called");
|
|
}
|
|
~FeatureValueHashEntry() { }
|
|
|
|
bool KeyEquals(const KeyTypePointer aKey) const;
|
|
static KeyTypePointer KeyToPointer(KeyType aKey) { return &aKey; }
|
|
static PLDHashNumber HashKey(const KeyTypePointer aKey);
|
|
enum { ALLOW_MEMMOVE = true };
|
|
|
|
FeatureValueHashKey mKey;
|
|
nsTArray<uint32_t> mValues;
|
|
};
|
|
|
|
nsTHashtable<FeatureValueHashEntry> mFontFeatureValues;
|
|
};
|
|
|
|
#endif
|