gecko-dev/layout/style/nsStyleUtil.cpp

255 lines
8.0 KiB
C++

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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/. */
#include <math.h>
#include "mozilla/Util.h"
#include "nsStyleUtil.h"
#include "nsCRT.h"
#include "nsStyleConsts.h"
#include "nsGkAtoms.h"
#include "nsIContent.h"
#include "nsINameSpaceManager.h"
#include "nsIURI.h"
#include "nsNetUtil.h"
#include "nsReadableUtils.h"
#include "nsTextFormatter.h"
#include "nsCSSProps.h"
#include "nsRuleNode.h"
using namespace mozilla;
//------------------------------------------------------------------------------
// Font Algorithm Code
//------------------------------------------------------------------------------
// Compare two language strings
bool nsStyleUtil::DashMatchCompare(const nsAString& aAttributeValue,
const nsAString& aSelectorValue,
const nsStringComparator& aComparator)
{
bool result;
uint32_t selectorLen = aSelectorValue.Length();
uint32_t attributeLen = aAttributeValue.Length();
if (selectorLen > attributeLen) {
result = false;
}
else {
nsAString::const_iterator iter;
if (selectorLen != attributeLen &&
*aAttributeValue.BeginReading(iter).advance(selectorLen) !=
PRUnichar('-')) {
// to match, the aAttributeValue must have a dash after the end of
// the aSelectorValue's text (unless the aSelectorValue and the
// aAttributeValue have the same text)
result = false;
}
else {
result = StringBeginsWith(aAttributeValue, aSelectorValue, aComparator);
}
}
return result;
}
void nsStyleUtil::AppendEscapedCSSString(const nsAString& aString,
nsAString& aReturn,
PRUnichar quoteChar)
{
NS_PRECONDITION(quoteChar == '\'' || quoteChar == '"',
"CSS strings must be quoted with ' or \"");
aReturn.Append(quoteChar);
const PRUnichar* in = aString.BeginReading();
const PRUnichar* const end = aString.EndReading();
for (; in != end; in++) {
if (*in < 0x20 || (*in >= 0x7F && *in < 0xA0)) {
// Escape U+0000 through U+001F and U+007F through U+009F numerically.
aReturn.AppendPrintf("\\%hX ", *in);
} else {
if (*in == '"' || *in == '\'' || *in == '\\') {
// Escape backslash and quote characters symbolically.
// It's not technically necessary to escape the quote
// character that isn't being used to delimit the string,
// but we do it anyway because that makes testing simpler.
aReturn.Append(PRUnichar('\\'));
}
aReturn.Append(*in);
}
}
aReturn.Append(quoteChar);
}
/* static */ void
nsStyleUtil::AppendEscapedCSSIdent(const nsAString& aIdent, nsAString& aReturn)
{
// The relevant parts of the CSS grammar are:
// ident [-]?{nmstart}{nmchar}*
// nmstart [_a-z]|{nonascii}|{escape}
// nmchar [_a-z0-9-]|{nonascii}|{escape}
// nonascii [^\0-\177]
// escape {unicode}|\\[^\n\r\f0-9a-f]
// unicode \\[0-9a-f]{1,6}(\r\n|[ \n\r\t\f])?
// from http://www.w3.org/TR/CSS21/syndata.html#tokenization
const PRUnichar* in = aIdent.BeginReading();
const PRUnichar* const end = aIdent.EndReading();
if (in == end)
return;
// A leading dash does not need to be escaped as long as it is not the
// *only* character in the identifier.
if (in + 1 != end && *in == '-') {
aReturn.Append(PRUnichar('-'));
++in;
}
// Escape a digit at the start (including after a dash),
// numerically. If we didn't escape it numerically, it would get
// interpreted as a numeric escape for the wrong character.
// A second dash immediately after a leading dash must also be
// escaped, but this may be done symbolically.
if (in != end && (*in == '-' ||
('0' <= *in && *in <= '9'))) {
if (*in == '-') {
aReturn.Append(PRUnichar('\\'));
aReturn.Append(PRUnichar('-'));
} else {
aReturn.AppendPrintf("\\%hX ", *in);
}
++in;
}
for (; in != end; ++in) {
PRUnichar ch = *in;
if (ch < 0x20 || (0x7F <= ch && ch < 0xA0)) {
// Escape U+0000 through U+001F and U+007F through U+009F numerically.
aReturn.AppendPrintf("\\%hX ", *in);
} else {
// Escape ASCII non-identifier printables as a backslash plus
// the character.
if (ch < 0x7F &&
ch != '_' && ch != '-' &&
(ch < '0' || '9' < ch) &&
(ch < 'A' || 'Z' < ch) &&
(ch < 'a' || 'z' < ch)) {
aReturn.Append(PRUnichar('\\'));
}
aReturn.Append(ch);
}
}
}
/* static */ void
nsStyleUtil::AppendBitmaskCSSValue(nsCSSProperty aProperty,
int32_t aMaskedValue,
int32_t aFirstMask,
int32_t aLastMask,
nsAString& aResult)
{
for (int32_t mask = aFirstMask; mask <= aLastMask; mask <<= 1) {
if (mask & aMaskedValue) {
AppendASCIItoUTF16(nsCSSProps::LookupPropertyValue(aProperty, mask),
aResult);
aMaskedValue &= ~mask;
if (aMaskedValue) { // more left
aResult.Append(PRUnichar(' '));
}
}
}
NS_ABORT_IF_FALSE(aMaskedValue == 0, "unexpected bit remaining in bitfield");
}
/* static */ void
nsStyleUtil::AppendFontFeatureSettings(const nsTArray<gfxFontFeature>& aFeatures,
nsAString& aResult)
{
for (uint32_t i = 0, numFeat = aFeatures.Length(); i < numFeat; i++) {
const gfxFontFeature& feat = aFeatures[i];
if (i != 0) {
aResult.AppendLiteral(", ");
}
// output tag
char tag[7];
tag[0] = '"';
tag[1] = (feat.mTag >> 24) & 0xff;
tag[2] = (feat.mTag >> 16) & 0xff;
tag[3] = (feat.mTag >> 8) & 0xff;
tag[4] = feat.mTag & 0xff;
tag[5] = '"';
tag[6] = 0;
aResult.AppendASCII(tag);
// output value, if necessary
if (feat.mValue == 0) {
// 0 ==> off
aResult.AppendLiteral(" off");
} else if (feat.mValue > 1) {
aResult.AppendLiteral(" ");
aResult.AppendInt(feat.mValue);
}
// else, omit value if 1, implied by default
}
}
/* static */ void
nsStyleUtil::AppendFontFeatureSettings(const nsCSSValue& aSrc,
nsAString& aResult)
{
nsCSSUnit unit = aSrc.GetUnit();
if (unit == eCSSUnit_Normal) {
aResult.AppendLiteral("normal");
return;
}
NS_PRECONDITION(unit == eCSSUnit_PairList || unit == eCSSUnit_PairListDep,
"improper value unit for font-feature-settings:");
nsTArray<gfxFontFeature> featureSettings;
nsRuleNode::ComputeFontFeatures(aSrc.GetPairListValue(), featureSettings);
AppendFontFeatureSettings(featureSettings, aResult);
}
/* static */ float
nsStyleUtil::ColorComponentToFloat(uint8_t aAlpha)
{
// Alpha values are expressed as decimals, so we should convert
// back, using as few decimal places as possible for
// round-tripping.
// First try two decimal places:
float rounded = NS_roundf(float(aAlpha) * 100.0f / 255.0f) / 100.0f;
if (FloatToColorComponent(rounded) != aAlpha) {
// Use three decimal places.
rounded = NS_roundf(float(aAlpha) * 1000.0f / 255.0f) / 1000.0f;
}
return rounded;
}
/* static */ bool
nsStyleUtil::IsSignificantChild(nsIContent* aChild, bool aTextIsSignificant,
bool aWhitespaceIsSignificant)
{
NS_ASSERTION(!aWhitespaceIsSignificant || aTextIsSignificant,
"Nonsensical arguments");
bool isText = aChild->IsNodeOfType(nsINode::eTEXT);
if (!isText && !aChild->IsNodeOfType(nsINode::eCOMMENT) &&
!aChild->IsNodeOfType(nsINode::ePROCESSING_INSTRUCTION)) {
return true;
}
return aTextIsSignificant && isText && aChild->TextLength() != 0 &&
(aWhitespaceIsSignificant ||
!aChild->TextIsOnlyWhitespace());
}