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nsStyleUtil.cpp
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nsStyleUtil.cpp
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/* -*- 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 "nsStyleUtil.h"
#include "nsStyleConsts.h"
#include "nsIContent.h"
#include "nsReadableUtils.h"
#include "nsCSSProps.h"
#include "nsRuleNode.h"
#include "nsIContentSecurityPolicy.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::AppendPaintOrderValue(uint8_t aValue,
nsAString& aResult)
{
static_assert
(NS_STYLE_PAINT_ORDER_BITWIDTH * NS_STYLE_PAINT_ORDER_LAST_VALUE <= 8,
"SVGStyleStruct::mPaintOrder and local variables not big enough");
if (aValue == NS_STYLE_PAINT_ORDER_NORMAL) {
aResult.AppendLiteral("normal");
return;
}
// Append the minimal value necessary for the given paint order.
static_assert(NS_STYLE_PAINT_ORDER_LAST_VALUE == 3,
"paint-order values added; check serialization");
// The following relies on the default order being the order of the
// constant values.
const uint8_t MASK = (1 << NS_STYLE_PAINT_ORDER_BITWIDTH) - 1;
uint32_t lastPositionToSerialize = 0;
for (uint32_t position = NS_STYLE_PAINT_ORDER_LAST_VALUE - 1;
position > 0;
position--) {
uint8_t component =
(aValue >> (position * NS_STYLE_PAINT_ORDER_BITWIDTH)) & MASK;
uint8_t earlierComponent =
(aValue >> ((position - 1) * NS_STYLE_PAINT_ORDER_BITWIDTH)) & MASK;
if (component < earlierComponent) {
lastPositionToSerialize = position - 1;
break;
}
}
for (uint32_t position = 0; position <= lastPositionToSerialize; position++) {
if (position > 0) {
aResult.AppendLiteral(" ");
}
uint8_t component = aValue & MASK;
switch (component) {
case NS_STYLE_PAINT_ORDER_FILL:
aResult.AppendLiteral("fill");
break;
case NS_STYLE_PAINT_ORDER_STROKE:
aResult.AppendLiteral("stroke");
break;
case NS_STYLE_PAINT_ORDER_MARKERS:
aResult.AppendLiteral("markers");
break;
default:
NS_NOTREACHED("unexpected paint-order component value");
}
aValue >>= NS_STYLE_PAINT_ORDER_BITWIDTH;
}
}
/* 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 */ void
nsStyleUtil::GetFunctionalAlternatesName(int32_t aFeature,
nsAString& aFeatureName)
{
aFeatureName.Truncate();
nsCSSKeyword key =
nsCSSProps::ValueToKeywordEnum(aFeature,
nsCSSProps::kFontVariantAlternatesFuncsKTable);
NS_ASSERTION(key != eCSSKeyword_UNKNOWN, "bad alternate feature type");
AppendUTF8toUTF16(nsCSSKeywords::GetStringValue(key), aFeatureName);
}
/* static */ void
nsStyleUtil::SerializeFunctionalAlternates(
const nsTArray<gfxAlternateValue>& aAlternates,
nsAString& aResult)
{
nsAutoString funcName, funcParams;
uint32_t numValues = aAlternates.Length();
uint32_t feature = 0;
for (uint32_t i = 0; i < numValues; i++) {
const gfxAlternateValue& v = aAlternates.ElementAt(i);
if (feature != v.alternate) {
feature = v.alternate;
if (!funcName.IsEmpty() && !funcParams.IsEmpty()) {
if (!aResult.IsEmpty()) {
aResult.Append(PRUnichar(' '));
}
// append the previous functional value
aResult.Append(funcName);
aResult.Append(PRUnichar('('));
aResult.Append(funcParams);
aResult.Append(PRUnichar(')'));
}
// function name
GetFunctionalAlternatesName(v.alternate, funcName);
NS_ASSERTION(!funcName.IsEmpty(), "unknown property value name");
// function params
funcParams.Truncate();
AppendEscapedCSSIdent(v.value, funcParams);
} else {
if (!funcParams.IsEmpty()) {
funcParams.Append(NS_LITERAL_STRING(", "));
}
AppendEscapedCSSIdent(v.value, funcParams);
}
}
// append the previous functional value
if (!funcName.IsEmpty() && !funcParams.IsEmpty()) {
if (!aResult.IsEmpty()) {
aResult.Append(PRUnichar(' '));
}
aResult.Append(funcName);
aResult.Append(PRUnichar('('));
aResult.Append(funcParams);
aResult.Append(PRUnichar(')'));
}
}
/* static */ void
nsStyleUtil::ComputeFunctionalAlternates(const nsCSSValueList* aList,
nsTArray<gfxAlternateValue>& aAlternateValues)
{
gfxAlternateValue v;
aAlternateValues.Clear();
for (const nsCSSValueList* curr = aList; curr != nullptr; curr = curr->mNext) {
// list contains function units
if (curr->mValue.GetUnit() != eCSSUnit_Function) {
continue;
}
// element 0 is the propval in ident form
const nsCSSValue::Array *func = curr->mValue.GetArrayValue();
// lookup propval
nsCSSKeyword key = func->Item(0).GetKeywordValue();
NS_ASSERTION(key != eCSSKeyword_UNKNOWN, "unknown alternate property value");
int32_t alternate;
if (key == eCSSKeyword_UNKNOWN ||
!nsCSSProps::FindKeyword(key,
nsCSSProps::kFontVariantAlternatesFuncsKTable,
alternate)) {
NS_NOTREACHED("keyword not a font-variant-alternates value");
}
v.alternate = alternate;
// other elements are the idents associated with the propval
// append one alternate value for each one
uint32_t numElems = func->Count();
for (uint32_t i = 1; i < numElems; i++) {
const nsCSSValue& value = func->Item(i);
NS_ASSERTION(value.GetUnit() == eCSSUnit_Ident,
"weird unit found in variant alternate");
if (value.GetUnit() != eCSSUnit_Ident) {
continue;
}
value.GetStringValue(v.value);
aAlternateValues.AppendElement(v);
}
}
}
/* 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());
}
/* static */ bool
nsStyleUtil::CSPAllowsInlineStyle(nsIPrincipal* aPrincipal,
nsIURI* aSourceURI,
uint32_t aLineNumber,
const nsSubstring& aStyleText,
nsresult* aRv)
{
nsresult rv;
if (aRv) {
*aRv = NS_OK;
}
nsCOMPtr<nsIContentSecurityPolicy> csp;
rv = aPrincipal->GetCsp(getter_AddRefs(csp));
if (NS_FAILED(rv)) {
if (aRv)
*aRv = rv;
return false;
}
if (csp) {
bool inlineOK = true;
bool reportViolation = false;
rv = csp->GetAllowsInlineStyle(&reportViolation, &inlineOK);
if (NS_FAILED(rv)) {
if (aRv)
*aRv = rv;
return false;
}
if (reportViolation) {
// Inline styles are not allowed by CSP, so report the violation
nsAutoCString asciiSpec;
aSourceURI->GetAsciiSpec(asciiSpec);
nsAutoString styleText(aStyleText);
// cap the length of the style sample at 40 chars.
if (styleText.Length() > 40) {
styleText.Truncate(40);
styleText.Append(NS_LITERAL_STRING("..."));
}
csp->LogViolationDetails(nsIContentSecurityPolicy::VIOLATION_TYPE_INLINE_STYLE,
NS_ConvertUTF8toUTF16(asciiSpec),
aStyleText,
aLineNumber);
}
if (!inlineOK) {
// The inline style should be blocked.
return false;
}
}
// No CSP or a CSP that allows inline styles.
return true;
}