gecko/layout/style/nsStyleUtil.cpp
Ryan VanderMeulen a390eae5a3 Backed out 5 changesets (bug 965022) for mochitest-2 failures on a CLOSED TREE.
Backed out changeset 7f68752ffe1e (bug 965022)
Backed out changeset 24251d4da019 (bug 965022)
Backed out changeset a34ae046c947 (bug 965022)
Backed out changeset f747fd154739 (bug 965022)
Backed out changeset f076faf3c282 (bug 965022)
2014-08-26 16:02:37 -04:00

702 lines
22 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 "nsStyleUtil.h"
#include "nsStyleConsts.h"
#include "nsIContent.h"
#include "nsCSSProps.h"
#include "nsRuleNode.h"
#include "nsROCSSPrimitiveValue.h"
#include "nsIContentPolicy.h"
#include "nsIContentSecurityPolicy.h"
#include "nsIURI.h"
#include "nsPrintfCString.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) !=
char16_t('-')) {
// 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,
char16_t quoteChar)
{
NS_PRECONDITION(quoteChar == '\'' || quoteChar == '"',
"CSS strings must be quoted with ' or \"");
aReturn.Append(quoteChar);
const char16_t* in = aString.BeginReading();
const char16_t* 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(char16_t('\\'));
}
aReturn.Append(*in);
}
}
aReturn.Append(quoteChar);
}
/* static */ bool
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 but
// modified for idents by
// http://dev.w3.org/csswg/cssom/#serialize-an-identifier and
// http://dev.w3.org/csswg/css-syntax/#would-start-an-identifier
const char16_t* in = aIdent.BeginReading();
const char16_t* const end = aIdent.EndReading();
if (in == end)
return true;
// A leading dash does not need to be escaped as long as it is not the
// *only* character in the identifier.
if (*in == '-') {
if (in + 1 == end) {
aReturn.Append(char16_t('\\'));
aReturn.Append(char16_t('-'));
return true;
}
aReturn.Append(char16_t('-'));
++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.
if (in != end && ('0' <= *in && *in <= '9')) {
aReturn.AppendPrintf("\\%hX ", *in);
++in;
}
for (; in != end; ++in) {
char16_t ch = *in;
if (ch == 0x00) {
return false;
}
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(char16_t('\\'));
}
aReturn.Append(ch);
}
}
return true;
}
// unquoted family names must be a sequence of idents
// so escape any parts that require escaping
static void
AppendUnquotedFamilyName(const nsAString& aFamilyName, nsAString& aResult)
{
const char16_t *p, *p_end;
aFamilyName.BeginReading(p);
aFamilyName.EndReading(p_end);
bool moreThanOne = false;
while (p < p_end) {
const char16_t* identStart = p;
while (++p != p_end && *p != ' ')
/* nothing */ ;
nsDependentSubstring ident(identStart, p);
if (!ident.IsEmpty()) {
if (moreThanOne) {
aResult.Append(' ');
}
nsStyleUtil::AppendEscapedCSSIdent(ident, aResult);
moreThanOne = true;
}
++p;
}
}
/* static */ void
nsStyleUtil::AppendEscapedCSSFontFamilyList(
const mozilla::FontFamilyList& aFamilyList,
nsAString& aResult)
{
const nsTArray<FontFamilyName>& fontlist = aFamilyList.GetFontlist();
size_t i, len = fontlist.Length();
for (i = 0; i < len; i++) {
if (i != 0) {
aResult.Append(',');
}
const FontFamilyName& name = fontlist[i];
switch (name.mType) {
case eFamily_named:
AppendUnquotedFamilyName(name.mName, aResult);
break;
case eFamily_named_quoted:
AppendEscapedCSSString(name.mName, aResult);
break;
default:
name.AppendToString(aResult);
}
}
}
/* 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(char16_t(' '));
}
}
}
NS_ABORT_IF_FALSE(aMaskedValue == 0, "unexpected bit remaining in bitfield");
}
/* static */ void
nsStyleUtil::AppendAngleValue(const nsStyleCoord& aAngle, nsAString& aResult)
{
MOZ_ASSERT(aAngle.IsAngleValue(), "Should have angle value");
// Append number.
AppendCSSNumber(aAngle.GetAngleValue(), aResult);
// Append unit.
switch (aAngle.GetUnit()) {
case eStyleUnit_Degree: aResult.AppendLiteral("deg"); break;
case eStyleUnit_Grad: aResult.AppendLiteral("grad"); break;
case eStyleUnit_Radian: aResult.AppendLiteral("rad"); break;
case eStyleUnit_Turn: aResult.AppendLiteral("turn"); break;
default: NS_NOTREACHED("unrecognized angle unit");
}
}
/* 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.Append(' ');
}
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.Append(' ');
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(char16_t(' '));
}
// append the previous functional value
aResult.Append(funcName);
aResult.Append(char16_t('('));
aResult.Append(funcParams);
aResult.Append(char16_t(')'));
}
// 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.AppendLiteral(", ");
}
AppendEscapedCSSIdent(v.value, funcParams);
}
}
// append the previous functional value
if (!funcName.IsEmpty() && !funcParams.IsEmpty()) {
if (!aResult.IsEmpty()) {
aResult.Append(char16_t(' '));
}
aResult.Append(funcName);
aResult.Append(char16_t('('));
aResult.Append(funcParams);
aResult.Append(char16_t(')'));
}
}
/* 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");
continue;
}
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);
}
}
}
// print all characters with at least four hex digits
static void
AppendSerializedUnicodePoint(uint32_t aCode, nsACString& aBuf)
{
aBuf.Append(nsPrintfCString("%04X", aCode));
}
// A unicode-range: descriptor is represented as an array of integers,
// to be interpreted as a sequence of pairs: min max min max ...
// It is in source order. (Possibly it should be sorted and overlaps
// consolidated, but right now we don't do that.)
/* static */ void
nsStyleUtil::AppendUnicodeRange(const nsCSSValue& aValue, nsAString& aResult)
{
NS_PRECONDITION(aValue.GetUnit() == eCSSUnit_Null ||
aValue.GetUnit() == eCSSUnit_Array,
"improper value unit for unicode-range:");
aResult.Truncate();
if (aValue.GetUnit() != eCSSUnit_Array)
return;
nsCSSValue::Array const & sources = *aValue.GetArrayValue();
nsAutoCString buf;
NS_ABORT_IF_FALSE(sources.Count() % 2 == 0,
"odd number of entries in a unicode-range: array");
for (uint32_t i = 0; i < sources.Count(); i += 2) {
uint32_t min = sources[i].GetIntValue();
uint32_t max = sources[i+1].GetIntValue();
// We don't try to replicate the U+XX?? notation.
buf.AppendLiteral("U+");
AppendSerializedUnicodePoint(min, buf);
if (min != max) {
buf.Append('-');
AppendSerializedUnicodePoint(max, buf);
}
buf.AppendLiteral(", ");
}
buf.Truncate(buf.Length() - 2); // remove the last comma-space
CopyASCIItoUTF16(buf, 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());
}
/* static */ bool
nsStyleUtil::IsFlexBasisMainSize(const nsStyleCoord& aFlexBasis,
bool aIsMainAxisHorizontal)
{
// "main-size" is stored as an enumerated value; so if we're not enumerated,
// we're not "main-size".
if (aFlexBasis.GetUnit() != eStyleUnit_Enumerated) {
return false;
}
if (!aIsMainAxisHorizontal) {
// Special case for vertical flex items: We don't support any enumerated
// values (e.g. "-moz-max-content") for "height"-flavored properties
// yet. So, if our computed flex-basis is *any* enumerated value, we'll
// just behave as if it were "main-size" (the initial value of flex-basis).
// NOTE: Once we support intrinsic sizing keywords for "height",
// we can remove this special-case.
return true;
}
return aFlexBasis.GetIntValue() == NS_STYLE_FLEX_BASIS_MAIN_SIZE;
}
/* static */ bool
nsStyleUtil::CSPAllowsInlineStyle(nsIContent* aContent,
nsIPrincipal* aPrincipal,
nsIURI* aSourceURI,
uint32_t aLineNumber,
const nsSubstring& aStyleText,
nsresult* aRv)
{
nsresult rv;
if (aRv) {
*aRv = NS_OK;
}
MOZ_ASSERT(!aContent || aContent->Tag() == nsGkAtoms::style,
"aContent passed to CSPAllowsInlineStyle "
"for an element that is not <style>");
nsCOMPtr<nsIContentSecurityPolicy> csp;
rv = aPrincipal->GetCsp(getter_AddRefs(csp));
if (NS_FAILED(rv)) {
if (aRv)
*aRv = rv;
return false;
}
if (!csp) {
// No CSP --> the style is allowed
return true;
}
// An inline style can be allowed because all inline styles are allowed,
// or else because it is whitelisted by a nonce-source or hash-source. This
// is a logical OR between whitelisting methods, so the allowInlineStyle
// outparam can be reused for each check as long as we stop checking as soon
// as it is set to true. This also optimizes performance by avoiding the
// overhead of unnecessary checks.
bool allowInlineStyle = true;
nsAutoTArray<unsigned short, 3> violations;
bool reportInlineViolation;
rv = csp->GetAllowsInlineStyle(&reportInlineViolation, &allowInlineStyle);
if (NS_FAILED(rv)) {
if (aRv)
*aRv = rv;
return false;
}
if (reportInlineViolation) {
violations.AppendElement(static_cast<unsigned short>(
nsIContentSecurityPolicy::VIOLATION_TYPE_INLINE_STYLE));
}
nsAutoString nonce;
if (!allowInlineStyle) {
// We can only find a nonce if aContent is provided
bool foundNonce = !!aContent &&
aContent->GetAttr(kNameSpaceID_None, nsGkAtoms::nonce, nonce);
if (foundNonce) {
bool reportNonceViolation;
rv = csp->GetAllowsNonce(nonce, nsIContentPolicy::TYPE_STYLESHEET,
&reportNonceViolation, &allowInlineStyle);
if (NS_FAILED(rv)) {
if (aRv)
*aRv = rv;
return false;
}
if (reportNonceViolation) {
violations.AppendElement(static_cast<unsigned short>(
nsIContentSecurityPolicy::VIOLATION_TYPE_NONCE_STYLE));
}
}
}
if (!allowInlineStyle) {
bool reportHashViolation;
rv = csp->GetAllowsHash(aStyleText, nsIContentPolicy::TYPE_STYLESHEET,
&reportHashViolation, &allowInlineStyle);
if (NS_FAILED(rv)) {
if (aRv)
*aRv = rv;
return false;
}
if (reportHashViolation) {
violations.AppendElement(static_cast<unsigned short>(
nsIContentSecurityPolicy::VIOLATION_TYPE_HASH_STYLE));
}
}
// What violation(s) should be reported?
//
// 1. If the style tag has a nonce attribute, and the nonce does not match
// the policy, report VIOLATION_TYPE_NONCE_STYLE.
// 2. If the policy has at least one hash-source, and the hashed contents of
// the style tag did not match any of them, report VIOLATION_TYPE_HASH_STYLE
// 3. Otherwise, report VIOLATION_TYPE_INLINE_STYLE if appropriate.
//
// 1 and 2 may occur together, 3 should only occur by itself. Naturally,
// every VIOLATION_TYPE_NONCE_STYLE and VIOLATION_TYPE_HASH_STYLE are also
// VIOLATION_TYPE_INLINE_STYLE, but reporting the
// VIOLATION_TYPE_INLINE_STYLE is redundant and does not help the developer.
if (!violations.IsEmpty()) {
MOZ_ASSERT(violations[0] == nsIContentSecurityPolicy::VIOLATION_TYPE_INLINE_STYLE,
"How did we get any violations without an initial inline style violation?");
// This inline style is not allowed by CSP, so report the violation
nsAutoCString asciiSpec;
aSourceURI->GetAsciiSpec(asciiSpec);
nsAutoString styleSample(aStyleText);
// cap the length of the style sample at 40 chars.
if (styleSample.Length() > 40) {
styleSample.Truncate(40);
styleSample.AppendLiteral("...");
}
for (uint32_t i = 0; i < violations.Length(); i++) {
// Skip reporting the redundant inline style violation if there are
// other (nonce and/or hash violations) as well.
if (i > 0 || violations.Length() == 1) {
csp->LogViolationDetails(violations[i], NS_ConvertUTF8toUTF16(asciiSpec),
styleSample, aLineNumber, nonce, aStyleText);
}
}
}
if (!allowInlineStyle) {
NS_ASSERTION(!violations.IsEmpty(),
"CSP blocked inline style but is not reporting a violation");
// The inline style should be blocked.
return false;
}
// CSP allows inline styles.
return true;
}