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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* 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
#include "nsStyleUtil.h"
#include "nsStyleConsts.h"
#include "mozilla/dom/Document.h"
#include "mozilla/ExpandedPrincipal.h"
#include "mozilla/intl/MozLocaleBindings.h"
#include "mozilla/intl/oxilangtag_ffi_generated.h"
#include "mozilla/TextUtils.h"
#include "nsIContent.h"
#include "nsCSSProps.h"
#include "nsContentUtils.h"
#include "nsROCSSPrimitiveValue.h"
#include "nsStyleStruct.h"
#include "nsIContentPolicy.h"
#include "nsIContentSecurityPolicy.h"
#include "nsLayoutUtils.h"
#include "nsPrintfCString.h"
#include <cctype>
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;
}
bool nsStyleUtil::LangTagCompare(const nsACString& aAttributeValue,
const nsACString& aSelectorValue) {
if (aAttributeValue.IsEmpty() || aSelectorValue.IsEmpty()) {
return false;
}
class MOZ_RAII AutoLangTag final {
public:
AutoLangTag() = delete;
AutoLangTag(const AutoLangTag& aOther) = delete;
explicit AutoLangTag(const nsACString& aLangTag) {
mLangTag = intl::ffi::lang_tag_new(&aLangTag);
}
~AutoLangTag() {
if (mLangTag) {
intl::ffi::lang_tag_destroy(mLangTag);
}
}
bool IsValid() const { return mLangTag; }
operator intl::ffi::LangTag*() const { return mLangTag; }
void Reset(const nsACString& aLangTag) {
if (mLangTag) {
intl::ffi::lang_tag_destroy(mLangTag);
}
mLangTag = intl::ffi::lang_tag_new(&aLangTag);
}
private:
intl::ffi::LangTag* mLangTag = nullptr;
};
AutoLangTag langAttr(aAttributeValue);
// Non-BCP47 extension: recognize '_' as an alternative subtag delimiter.
nsAutoCString attrTemp;
if (!langAttr.IsValid()) {
if (aAttributeValue.Contains('_')) {
attrTemp = aAttributeValue;
attrTemp.ReplaceChar('_', '-');
langAttr.Reset(attrTemp);
}
}
if (!langAttr.IsValid()) {
return false;
}
return intl::ffi::lang_tag_matches(langAttr, &aSelectorValue);
}
bool nsStyleUtil::ValueIncludes(const nsAString& aValueList,
const nsAString& aValue,
const nsStringComparator& aComparator) {
const char16_t *p = aValueList.BeginReading(),
*p_end = aValueList.EndReading();
while (p < p_end) {
// skip leading space
while (p != p_end && nsContentUtils::IsHTMLWhitespace(*p)) {
++p;
}
const char16_t* val_start = p;
// look for space or end
while (p != p_end && !nsContentUtils::IsHTMLWhitespace(*p)) {
++p;
}
const char16_t* val_end = p;
if (val_start < val_end &&
aValue.Equals(Substring(val_start, val_end), aComparator)) {
return true;
}
++p; // we know the next character is not whitespace
}
return false;
}
void nsStyleUtil::AppendEscapedCSSString(const nsAString& aString,
nsAString& aReturn,
char16_t quoteChar) {
MOZ_ASSERT(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) {
// Escape U+0000 through U+001F and U+007F numerically.
aReturn.AppendPrintf("\\%x ", *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 */
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])?
// modified for idents by
const char16_t* in = aIdent.BeginReading();
const char16_t* 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 == '-') {
if (in + 1 == end) {
aReturn.Append(char16_t('\\'));
aReturn.Append(char16_t('-'));
return;
}
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("\\%x ", *in);
++in;
}
for (; in != end; ++in) {
char16_t ch = *in;
if (ch == 0x00) {
aReturn.Append(char16_t(0xFFFD));
} else if (ch < 0x20 || 0x7F == ch) {
// Escape U+0000 through U+001F and U+007F numerically.
aReturn.AppendPrintf("\\%x ", *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);
}
}
}
/* 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 */
void nsStyleUtil::GetSerializedColorValue(nscolor aColor,
nsAString& aSerializedColor) {
MOZ_ASSERT(aSerializedColor.IsEmpty());
const bool hasAlpha = NS_GET_A(aColor) != 255;
if (hasAlpha) {
aSerializedColor.AppendLiteral("rgba(");
} else {
aSerializedColor.AppendLiteral("rgb(");
}
aSerializedColor.AppendInt(NS_GET_R(aColor));
aSerializedColor.AppendLiteral(", ");
aSerializedColor.AppendInt(NS_GET_G(aColor));
aSerializedColor.AppendLiteral(", ");
aSerializedColor.AppendInt(NS_GET_B(aColor));
if (hasAlpha) {
aSerializedColor.AppendLiteral(", ");
float alpha = nsStyleUtil::ColorComponentToFloat(NS_GET_A(aColor));
nsStyleUtil::AppendCSSNumber(alpha, aSerializedColor);
}
aSerializedColor.AppendLiteral(")");
}
/* static */
bool nsStyleUtil::IsSignificantChild(nsIContent* aChild,
bool aWhitespaceIsSignificant) {
bool isText = aChild->IsText();
if (!isText && !aChild->IsComment() && !aChild->IsProcessingInstruction()) {
return true;
}
return isText && aChild->TextLength() != 0 &&
(aWhitespaceIsSignificant || !aChild->TextIsOnlyWhitespace());
}
/* static */
bool nsStyleUtil::ThreadSafeIsSignificantChild(const nsIContent* aChild,
bool aWhitespaceIsSignificant) {
bool isText = aChild->IsText();
if (!isText && !aChild->IsComment() && !aChild->IsProcessingInstruction()) {
return true;
}
return isText && aChild->TextLength() != 0 &&
(aWhitespaceIsSignificant ||
!aChild->ThreadSafeTextIsOnlyWhitespace());
}
// For a replaced element whose concrete object size is no larger than the
// element's content-box, this method checks whether the given
// "object-position" coordinate might cause overflow in its dimension.
static bool ObjectPositionCoordMightCauseOverflow(
const LengthPercentage& aCoord) {
// Any nonzero length in "object-position" can push us to overflow
// (particularly if our concrete object size is exactly the same size as the
// replaced element's content-box).
if (!aCoord.ConvertsToPercentage()) {
return !aCoord.ConvertsToLength() || aCoord.ToLengthInCSSPixels() != 0.0f;
}
// Percentages are interpreted as a fraction of the extra space. So,
// percentages in the 0-100% range are safe, but values outside of that
// range could cause overflow.
float percentage = aCoord.ToPercentage();
return percentage < 0.0f || percentage > 1.0f;
}
/* static */
bool nsStyleUtil::ObjectPropsMightCauseOverflow(
const nsStylePosition* aStylePos) {
auto objectFit = aStylePos->mObjectFit;
// "object-fit: cover" & "object-fit: none" can give us a render rect that's
// larger than our container element's content-box.
if (objectFit == StyleObjectFit::Cover || objectFit == StyleObjectFit::None) {
return true;
}
// (All other object-fit values produce a concrete object size that's no
// larger than the constraint region.)
// Check each of our "object-position" coords to see if it could cause
// overflow in its dimension:
const Position& objectPosistion = aStylePos->mObjectPosition;
if (ObjectPositionCoordMightCauseOverflow(objectPosistion.horizontal) ||
ObjectPositionCoordMightCauseOverflow(objectPosistion.vertical)) {
return true;
}
return false;
}
/* static */
bool nsStyleUtil::CSPAllowsInlineStyle(
dom::Element* aElement, dom::Document* aDocument,
nsIPrincipal* aTriggeringPrincipal, uint32_t aLineNumber,
uint32_t aColumnNumber, const nsAString& aStyleText, nsresult* aRv) {
nsresult rv;
if (aRv) {
*aRv = NS_OK;
}
nsCOMPtr<nsIContentSecurityPolicy> csp;
if (aTriggeringPrincipal && BasePrincipal::Cast(aTriggeringPrincipal)
->OverridesCSP(aDocument->NodePrincipal())) {
nsCOMPtr<nsIExpandedPrincipal> ep = do_QueryInterface(aTriggeringPrincipal);
if (ep) {
csp = ep->GetCsp();
}
} else {
csp = aDocument->GetCsp();
}
if (!csp) {
// No CSP --> the style is allowed
return true;
}
// Hack to allow Devtools to edit inline styles
if (csp->GetSkipAllowInlineStyleCheck()) {
return true;
}
bool isStyleElement = false;
// Query the nonce.
nsAutoString nonce;
if (aElement && aElement->NodeInfo()->NameAtom() == nsGkAtoms::style) {
isStyleElement = true;
nsString* cspNonce =
static_cast<nsString*>(aElement->GetProperty(nsGkAtoms::nonce));
if (cspNonce) {
nonce = *cspNonce;
}
}
bool allowInlineStyle = true;
rv = csp->GetAllowsInline(
isStyleElement ? nsIContentSecurityPolicy::STYLE_SRC_ELEM_DIRECTIVE
: nsIContentSecurityPolicy::STYLE_SRC_ATTR_DIRECTIVE,
!isStyleElement /* aHasUnsafeHash */, nonce,
false, // aParserCreated only applies to scripts
aElement, nullptr, // nsICSPEventListener
aStyleText, aLineNumber, aColumnNumber, &allowInlineStyle);
NS_ENSURE_SUCCESS(rv, false);
return allowInlineStyle;
}