layout/style/nsCSSPropertyIDSet.h
author Jonathan Chan <jyc@eqv.io>
Tue, 16 Aug 2016 18:46:58 -0700
changeset 309642 fe895421dfbe1f1f8f1fc6a39bb20774423a6d74
parent 309641 layout/style/nsCSSPropertySet.h@84ad59b127a8f1c2cc748e5c7e8613dd34f22c5b
child 309796 5aa02060f7c47a1d4c2c198c18ab7fc59771467b
permissions -rw-r--r--
Bug 1293739 - Part 2: Rename nsCSSPropertySet to nsCSSPropertyIDSet. r=dholbert The previous patch in this series renamed nsCSSProperty to nsCSSPropertyID. This patch renames nsCSSPropertySet to nsCSSPropertyIDSet accordingly. This patch is generated by the following commands (note: if you're running using OS X's sed, which accepts slightly different flags, you'll have to specify an actual backup suffix in -i, or use gsed from Homebrew): hg stat -c \ | cut -c 3- \ | tr '\n' '\0' \ | xargs -0 -P 8 gsed --follow-symlinks 's/\bnsCSSPropertySet\b/nsCSSPropertyIDSet/g' -i'' Then: hg mv layout/style/nsCSSPropertySet.h layout/style/nsCSSPropertyIDSet.h ... and finally, manually renaming nsCSSPropertySet in the include guard in nsCSSPropertyIDSet.h. (NOTE: Re-landing this patch on a CLOSED TREE to correctly-address the merge bustage that closed the tree.) MozReview-Commit-ID: ASUNs7FWbKP

/* 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/. */

/* bit vectors for sets of CSS properties */

#ifndef nsCSSPropertyIDSet_h__
#define nsCSSPropertyIDSet_h__

#include "mozilla/ArrayUtils.h"
#include "mozilla/PodOperations.h"

#include "nsCSSPropertyID.h"
#include <limits.h> // for CHAR_BIT

/**
 * nsCSSPropertyIDSet maintains a set of non-shorthand CSS properties.  In
 * other words, for each longhand CSS property we support, it has a bit
 * for whether that property is in the set.
 */
class nsCSSPropertyIDSet {
public:
    nsCSSPropertyIDSet() { Empty(); }
    // auto-generated copy-constructor OK

    void AssertInSetRange(nsCSSPropertyID aProperty) const {
        NS_ASSERTION(0 <= aProperty &&
                     aProperty < eCSSProperty_COUNT_no_shorthands,
                     "out of bounds");
    }

    // Conversion of aProperty to |size_t| after AssertInSetRange
    // lets the compiler generate significantly tighter code.

    void AddProperty(nsCSSPropertyID aProperty) {
        AssertInSetRange(aProperty);
        size_t p = aProperty;
        mProperties[p / kBitsInChunk] |=
          property_set_type(1) << (p % kBitsInChunk);
    }

    void RemoveProperty(nsCSSPropertyID aProperty) {
        AssertInSetRange(aProperty);
        size_t p = aProperty;
        mProperties[p / kBitsInChunk] &=
            ~(property_set_type(1) << (p % kBitsInChunk));
    }

    bool HasProperty(nsCSSPropertyID aProperty) const {
        AssertInSetRange(aProperty);
        size_t p = aProperty;
        return (mProperties[p / kBitsInChunk] &
                (property_set_type(1) << (p % kBitsInChunk))) != 0;
    }

    void Empty() {
        memset(mProperties, 0, sizeof(mProperties));
    }

    void AssertIsEmpty(const char* aText) const {
        for (size_t i = 0; i < mozilla::ArrayLength(mProperties); ++i) {
            NS_ASSERTION(mProperties[i] == 0, aText);
        }
    }

    bool Equals(const nsCSSPropertyIDSet& aOther) const {
      return mozilla::PodEqual(mProperties, aOther.mProperties);
    }

private:
    typedef unsigned long property_set_type;
public:
    // number of bits in |property_set_type|.
    static const size_t kBitsInChunk = sizeof(property_set_type)*CHAR_BIT;
    // number of |property_set_type|s in the set
    static const size_t kChunkCount =
        (eCSSProperty_COUNT_no_shorthands + kBitsInChunk - 1) / kBitsInChunk;

    /*
     * For fast enumeration of all the bits that are set, callers can
     * check each chunk against zero (since in normal cases few bits are
     * likely to be set).
     */
    bool HasPropertyInChunk(size_t aChunk) const {
        return mProperties[aChunk] != 0;
    }
    bool HasPropertyAt(size_t aChunk, size_t aBit) const {
        return (mProperties[aChunk] & (property_set_type(1) << aBit)) != 0;
    }
    static nsCSSPropertyID CSSPropertyAt(size_t aChunk, size_t aBit) {
        return nsCSSPropertyID(aChunk * kBitsInChunk + aBit);
    }

private:
    property_set_type mProperties[kChunkCount];
};

#endif /* !defined(nsCSSPropertyIDSet_h__) */