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/* 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
// This file holds various CSS parsing and rewriting utilities.
// Some entry points of note are:
// parseDeclarations - parse a CSS rule into declarations
// RuleRewriter - rewrite CSS rule text
// parsePseudoClassesAndAttributes - parse selector and extract
// pseudo-classes
// parseSingleValue - parse a single CSS property value
"use strict";
const {
InspectorCSSParserWrapper,
const {
COMMENT_PARSING_HEURISTIC_BYPASS_CHAR,
escapeCSSComment,
parseNamedDeclarations,
unescapeCSSComment,
loader.lazyRequireGetter(
this,
["getIndentationFromPrefs", "getIndentationFromString"],
true
);
// Used to test whether a newline appears anywhere in some text.
const NEWLINE_RX = /[\r\n]/;
// Used to test whether a bit of text starts an empty comment, either
// an "ordinary" /* ... */ comment, or a "heuristic bypass" comment
// like /*! ... */.
const EMPTY_COMMENT_START_RX = /^\/\*!?[ \r\n\t\f]*$/;
// Used to test whether a bit of text ends an empty comment.
const EMPTY_COMMENT_END_RX = /^[ \r\n\t\f]*\*\//;
// Used to test whether a string starts with a blank line.
const BLANK_LINE_RX = /^[ \t]*(?:\r\n|\n|\r|\f|$)/;
/**
* Return an object that can be used to rewrite declarations in some
* source text. The source text and parsing are handled in the same
* way as @see parseNamedDeclarations, with |parseComments| being true.
* Rewriting is done by calling one of the modification functions like
* setPropertyEnabled. The returned object has the same interface
* as @see RuleModificationList.
*
* An example showing how to disable the 3rd property in a rule:
*
* let rewriter = new RuleRewriter(isCssPropertyKnown, ruleActor,
* ruleActor.authoredText);
* rewriter.setPropertyEnabled(3, "color", false);
* rewriter.apply().then(() => { ... the change is made ... });
*
* The exported rewriting methods are |renameProperty|, |setPropertyEnabled|,
* |createProperty|, |setProperty|, and |removeProperty|. The |apply|
* method can be used to send the edited text to the StyleRuleActor;
* |getDefaultIndentation| is useful for the methods requiring a
* default indentation value; and |getResult| is useful for testing.
*
* Additionally, editing will set the |changedDeclarations| property
* on this object. This property has the same form as the |changed|
* property of the object returned by |getResult|.
*
* @param {Function} isCssPropertyKnown
* A function to check if the CSS property is known. This is either an
* internal server function or from the CssPropertiesFront.
* is completed then isCssPropertyKnown will not need to be passed in.
* The CssProperty front will be able to obtained directly from the
* RuleRewriter.
* @param {StyleRuleFront} rule The style rule to use. Note that this
* is only needed by the |apply| and |getDefaultIndentation| methods;
* and in particular for testing it can be |null|.
* @param {String} inputString The CSS source text to parse and modify.
* @return {Object} an object that can be used to rewrite the input text.
*/
function RuleRewriter(isCssPropertyKnown, rule, inputString) {
this.rule = rule;
this.isCssPropertyKnown = isCssPropertyKnown;
// The RuleRewriter sends CSS rules as text to the server, but with this modifications
// array, it also sends the list of changes so the server doesn't have to re-parse the
// rule if it needs to track what changed.
this.modifications = [];
// Keep track of which any declarations we had to rewrite while
// performing the requested action.
this.changedDeclarations = {};
// If not null, a promise that must be wait upon before |apply| can
// do its work.
this.editPromise = null;
// If the |defaultIndentation| property is set, then it is used;
// otherwise the RuleRewriter will try to compute the default
// indentation based on the style sheet's text. This override
// facility is for testing.
this.defaultIndentation = null;
this.startInitialization(inputString);
}
RuleRewriter.prototype = {
/**
* An internal function to initialize the rewriter with a given
* input string.
*
* @param {String} inputString the input to use
*/
startInitialization(inputString) {
this.inputString = inputString;
// Whether there are any newlines in the input text.
this.hasNewLine = /[\r\n]/.test(this.inputString);
// The declarations.
this.declarations = parseNamedDeclarations(
this.isCssPropertyKnown,
this.inputString,
true
);
this.decl = null;
this.result = null;
},
/**
* An internal function to complete initialization and set some
* properties for further processing.
*
* @param {Number} index The index of the property to modify
*/
completeInitialization(index) {
if (index < 0) {
throw new Error("Invalid index " + index + ". Expected positive integer");
}
// |decl| is the declaration to be rewritten, or null if there is no
// declaration corresponding to |index|.
// |result| is used to accumulate the result text.
if (index < this.declarations.length) {
this.decl = this.declarations[index];
this.result = this.inputString.substring(0, this.decl.offsets[0]);
} else {
this.decl = null;
this.result = this.inputString;
}
},
/**
* A helper function to compute the indentation of some text. This
* examines the rule's existing text to guess the indentation to use;
* unlike |getDefaultIndentation|, which examines the entire style
* sheet.
*
* @param {String} string the input text
* @param {Number} offset the offset at which to compute the indentation
* @return {String} the indentation at the indicated position
*/
getIndentation(string, offset) {
let originalOffset = offset;
for (--offset; offset >= 0; --offset) {
const c = string[offset];
if (c === "\r" || c === "\n" || c === "\f") {
return string.substring(offset + 1, originalOffset);
}
if (c !== " " && c !== "\t") {
// Found some non-whitespace character before we found a newline
// -- let's reset the starting point and keep going, as we saw
// something on the line before the declaration.
originalOffset = offset;
}
}
// Ran off the end.
return "";
},
/**
* Modify a property value to ensure it is "lexically safe" for
* insertion into a style sheet. This function doesn't attempt to
* ensure that the resulting text is a valid value for the given
* property; but rather just that inserting the text into the style
* sheet will not cause unwanted changes to other rules or
* declarations.
*
* @param {String} text The input text. This should include the trailing ";".
* @return {Array} An array of the form [anySanitized, text], where
* |anySanitized| is a boolean that indicates
* whether anything substantive has changed; and
* where |text| is the text that has been rewritten
* to be "lexically safe".
*/
sanitizePropertyValue(text) {
// Start by stripping any trailing ";". This is done here to
// avoid the case where the user types "url(" (which is turned
// into "url(;" by the rule view before coming here), being turned
// into "url(;)" by this code -- due to the way "url(...)" is
// parsed as a single token.
text = text.replace(/;$/, "");
const lexer = new InspectorCSSParserWrapper(text, { trackEOFChars: true });
let result = "";
let previousOffset = 0;
const parenStack = [];
let anySanitized = false;
// Push a closing paren on the stack.
const pushParen = (token, closer) => {
result =
result +
text.substring(previousOffset, token.startOffset) +
text.substring(token.startOffset, token.endOffset);
// We set the location of the paren in a funny way, to handle
// the case where we've seen a function token, where the paren
// appears at the end.
parenStack.push({ closer, offset: result.length - 1, token });
previousOffset = token.endOffset;
};
// Pop a closing paren from the stack.
const popSomeParens = closer => {
while (parenStack.length) {
const paren = parenStack.pop();
if (paren.closer === closer) {
return true;
}
// We need to handle non-closed url function differently, as performEOFFixup will
// only automatically close missing parenthesis `url`.
// In such case, don't do anything here.
if (
paren.closer === ")" &&
closer == null &&
paren.token.tokenType === "Function" &&
paren.token.value === "url"
) {
return true;
}
// Found a non-matching closing paren, so quote it. Note that
// these are processed in reverse order.
result =
result.substring(0, paren.offset) +
"\\" +
result.substring(paren.offset);
anySanitized = true;
}
return false;
};
let token;
while ((token = lexer.nextToken())) {
switch (token.tokenType) {
case "Semicolon":
// We simply drop the ";" here. This lets us cope with
// declarations that don't have a ";" and also other
// termination. The caller handles adding the ";" again.
result += text.substring(previousOffset, token.startOffset);
previousOffset = token.endOffset;
break;
case "CurlyBracketBlock":
pushParen(token, "}");
break;
case "ParenthesisBlock":
case "Function":
pushParen(token, ")");
break;
case "SquareBracketBlock":
pushParen(token, "]");
break;
case "CloseCurlyBracket":
case "CloseParenthesis":
case "CloseSquareBracket":
// Did we find an unmatched close bracket?
if (!popSomeParens(token.text)) {
// Copy out text from |previousOffset|.
result += text.substring(previousOffset, token.startOffset);
// Quote the offending symbol.
result += "\\" + token.text;
previousOffset = token.endOffset;
anySanitized = true;
}
break;
}
}
// Fix up any unmatched parens.
popSomeParens(null);
// Copy out any remaining text, then any needed terminators.
result += text.substring(previousOffset, text.length);
const eofFixup = lexer.performEOFFixup("");
if (eofFixup) {
anySanitized = true;
result += eofFixup;
}
return [anySanitized, result];
},
/**
* Start at |index| and skip whitespace
* backward in |string|. Return the index of the first
* non-whitespace character, or -1 if the entire string was
* whitespace.
* @param {String} string the input string
* @param {Number} index the index at which to start
* @return {Number} index of the first non-whitespace character, or -1
*/
skipWhitespaceBackward(string, index) {
for (
--index;
index >= 0 && (string[index] === " " || string[index] === "\t");
--index
) {
// Nothing.
}
return index;
},
/**
* Terminate a given declaration, if needed.
*
* @param {Number} index The index of the rule to possibly
* terminate. It might be invalid, so this
* function must check for that.
*/
maybeTerminateDecl(index) {
if (
index < 0 ||
index >= this.declarations.length ||
// No need to rewrite declarations in comments.
"commentOffsets" in this.declarations[index]
) {
return;
}
const termDecl = this.declarations[index];
let endIndex = termDecl.offsets[1];
// Due to an oddity of the lexer, we might have gotten a bit of
// extra whitespace in a trailing bad_url token -- so be sure to
// skip that as well.
endIndex = this.skipWhitespaceBackward(this.result, endIndex) + 1;
const trailingText = this.result.substring(endIndex);
if (termDecl.terminator) {
// Insert the terminator just at the end of the declaration,
// before any trailing whitespace.
this.result =
this.result.substring(0, endIndex) + termDecl.terminator + trailingText;
// In a couple of cases, we may have had to add something to
// terminate the declaration, but the termination did not
// actually affect the property's value -- and at this spot, we
// only care about reporting value changes. In particular, we
// might have added a plain ";", or we might have terminated a
// comment with "*/;". Neither of these affect the value.
if (termDecl.terminator !== ";" && termDecl.terminator !== "*/;") {
this.changedDeclarations[index] =
termDecl.value + termDecl.terminator.slice(0, -1);
}
}
// If the rule generally has newlines, but this particular
// declaration doesn't have a trailing newline, insert one now.
// Maybe this style is too weird to bother with.
if (this.hasNewLine && !NEWLINE_RX.test(trailingText)) {
this.result += "\n";
}
},
/**
* Sanitize the given property value and return the sanitized form.
* If the property is rewritten during sanitization, make a note in
* |changedDeclarations|.
*
* @param {String} text The property text.
* @param {Number} index The index of the property.
* @return {String} The sanitized text.
*/
sanitizeText(text, index) {
const [anySanitized, sanitizedText] = this.sanitizePropertyValue(text);
if (anySanitized) {
this.changedDeclarations[index] = sanitizedText;
}
return sanitizedText;
},
/**
* Rename a declaration.
*
* @param {Number} index index of the property in the rule.
* @param {String} name current name of the property
* @param {String} newName new name of the property
*/
renameProperty(index, name, newName) {
this.completeInitialization(index);
this.result += CSS.escape(newName);
// We could conceivably compute the name offsets instead so we
// could preserve white space and comments on the LHS of the ":".
this.completeCopying(this.decl.colonOffsets[0]);
this.modifications.push({ type: "set", index, name, newName });
},
/**
* Enable or disable a declaration
*
* @param {Number} index index of the property in the rule.
* @param {String} name current name of the property
* @param {Boolean} isEnabled true if the property should be enabled;
* false if it should be disabled
*/
setPropertyEnabled(index, name, isEnabled) {
this.completeInitialization(index);
const decl = this.decl;
const priority = decl.priority;
let copyOffset = decl.offsets[1];
if (isEnabled) {
// Enable it. First see if the comment start can be deleted.
const commentStart = decl.commentOffsets[0];
if (EMPTY_COMMENT_START_RX.test(this.result.substring(commentStart))) {
this.result = this.result.substring(0, commentStart);
} else {
this.result += "*/ ";
}
// Insert the name and value separately, so we can report
// sanitization changes properly.
const commentNamePart = this.inputString.substring(
decl.offsets[0],
decl.colonOffsets[1]
);
this.result += unescapeCSSComment(commentNamePart);
// When uncommenting, we must be sure to sanitize the text, to
// avoid things like /* decl: }; */, which will be accepted as
// a property but which would break the entire style sheet.
let newText = this.inputString.substring(
decl.colonOffsets[1],
decl.offsets[1]
);
newText = cssTrimRight(unescapeCSSComment(newText));
this.result += this.sanitizeText(newText, index) + ";";
// See if the comment end can be deleted.
const trailingText = this.inputString.substring(decl.offsets[1]);
if (EMPTY_COMMENT_END_RX.test(trailingText)) {
copyOffset = decl.commentOffsets[1];
} else {
this.result += " /*";
}
} else {
// Disable it. Note that we use our special comment syntax
// here.
const declText = this.inputString.substring(
decl.offsets[0],
decl.offsets[1]
);
this.result +=
"/*" +
COMMENT_PARSING_HEURISTIC_BYPASS_CHAR +
" " +
escapeCSSComment(declText) +
" */";
}
this.completeCopying(copyOffset);
if (isEnabled) {
this.modifications.push({
type: "set",
index,
name,
value: decl.value,
priority,
});
} else {
this.modifications.push({ type: "disable", index, name });
}
},
/**
* Return a promise that will be resolved to the default indentation
* of the rule. This is a helper for internalCreateProperty.
*
* @return {Promise} a promise that will be resolved to a string
* that holds the default indentation that should be used
* for edits to the rule.
*/
async getDefaultIndentation() {
if (!this.rule.parentStyleSheet) {
return null;
}
const prefIndent = getIndentationFromPrefs();
if (prefIndent) {
const { indentUnit, indentWithTabs } = prefIndent;
return indentWithTabs ? "\t" : " ".repeat(indentUnit);
}
const styleSheetsFront = await this.rule.targetFront.getFront(
"stylesheets"
);
const { str: source } = await styleSheetsFront.getText(
this.rule.parentStyleSheet.resourceId
);
const { indentUnit, indentWithTabs } = getIndentationFromString(source);
return indentWithTabs ? "\t" : " ".repeat(indentUnit);
},
/**
* An internal function to create a new declaration. This does all
* the work of |createProperty|.
*
* @param {Number} index index of the property in the rule.
* @param {String} name name of the new property
* @param {String} value value of the new property
* @param {String} priority priority of the new property; either
* the empty string or "important"
* @param {Boolean} enabled True if the new property should be
* enabled, false if disabled
* @return {Promise} a promise that is resolved when the edit has
* completed
*/
async internalCreateProperty(index, name, value, priority, enabled) {
this.completeInitialization(index);
let newIndentation = "";
if (this.hasNewLine) {
if (this.declarations.length) {
newIndentation = this.getIndentation(
this.inputString,
this.declarations[0].offsets[0]
);
} else if (this.defaultIndentation) {
newIndentation = this.defaultIndentation;
} else {
newIndentation = await this.getDefaultIndentation();
}
}
this.maybeTerminateDecl(index - 1);
// If we generally have newlines, and if skipping whitespace
// backward stops at a newline, then insert our text before that
// whitespace. This ensures the indentation we computed is what
// is actually used.
let savedWhitespace = "";
if (this.hasNewLine) {
const wsOffset = this.skipWhitespaceBackward(
this.result,
this.result.length
);
if (this.result[wsOffset] === "\r" || this.result[wsOffset] === "\n") {
savedWhitespace = this.result.substring(wsOffset + 1);
this.result = this.result.substring(0, wsOffset + 1);
}
}
let newText = CSS.escape(name) + ": " + this.sanitizeText(value, index);
if (priority === "important") {
newText += " !important";
}
newText += ";";
if (!enabled) {
newText =
"/*" +
COMMENT_PARSING_HEURISTIC_BYPASS_CHAR +
" " +
escapeCSSComment(newText) +
" */";
}
this.result += newIndentation + newText;
if (this.hasNewLine) {
this.result += "\n";
}
this.result += savedWhitespace;
if (this.decl) {
// Still want to copy in the declaration previously at this
// index.
this.completeCopying(this.decl.offsets[0]);
}
},
/**
* Create a new declaration.
*
* @param {Number} index index of the property in the rule.
* @param {String} name name of the new property
* @param {String} value value of the new property
* @param {String} priority priority of the new property; either
* the empty string or "important"
* @param {Boolean} enabled True if the new property should be
* enabled, false if disabled
*/
createProperty(index, name, value, priority, enabled) {
this.editPromise = this.internalCreateProperty(
index,
name,
value,
priority,
enabled
);
// Log the modification only if the created property is enabled.
if (enabled) {
this.modifications.push({ type: "set", index, name, value, priority });
}
},
/**
* Set a declaration's value.
*
* @param {Number} index index of the property in the rule.
* This can be -1 in the case where
* the rule does not support setRuleText;
* generally for setting properties
* on an element's style.
* @param {String} name the property's name
* @param {String} value the property's value
* @param {String} priority the property's priority, either the empty
* string or "important"
*/
setProperty(index, name, value, priority) {
this.completeInitialization(index);
// We might see a "set" on a previously non-existent property; in
// that case, act like "create".
if (!this.decl) {
this.createProperty(index, name, value, priority, true);
return;
}
// Note that this assumes that "set" never operates on disabled
// properties.
this.result +=
this.inputString.substring(
this.decl.offsets[0],
this.decl.colonOffsets[1]
) + this.sanitizeText(value, index);
if (priority === "important") {
this.result += " !important";
}
this.result += ";";
this.completeCopying(this.decl.offsets[1]);
this.modifications.push({ type: "set", index, name, value, priority });
},
/**
* Remove a declaration.
*
* @param {Number} index index of the property in the rule.
* @param {String} name the name of the property to remove
*/
removeProperty(index, name) {
this.completeInitialization(index);
// If asked to remove a property that does not exist, bail out.
if (!this.decl) {
return;
}
// If the property is disabled, then first enable it, and then
// delete it. We take this approach because we want to remove the
// entire comment if possible; but the logic for dealing with
// comments is hairy and already implemented in
// setPropertyEnabled.
if (this.decl.commentOffsets) {
this.setPropertyEnabled(index, name, true);
this.startInitialization(this.result);
this.completeInitialization(index);
}
let copyOffset = this.decl.offsets[1];
// Maybe removing this rule left us with a completely blank
// line. In this case, we'll delete the whole thing. We only
// bother with this if we're looking at sources that already
// have a newline somewhere.
if (this.hasNewLine) {
const nlOffset = this.skipWhitespaceBackward(
this.result,
this.decl.offsets[0]
);
if (
nlOffset < 0 ||
this.result[nlOffset] === "\r" ||
this.result[nlOffset] === "\n"
) {
const trailingText = this.inputString.substring(copyOffset);
const match = BLANK_LINE_RX.exec(trailingText);
if (match) {
this.result = this.result.substring(0, nlOffset + 1);
copyOffset += match[0].length;
}
}
}
this.completeCopying(copyOffset);
this.modifications.push({ type: "remove", index, name });
},
/**
* An internal function to copy any trailing text to the output
* string.
*
* @param {Number} copyOffset Offset into |inputString| of the
* final text to copy to the output string.
*/
completeCopying(copyOffset) {
// Add the trailing text.
this.result += this.inputString.substring(copyOffset);
},
/**
* Apply the modifications in this object to the associated rule.
*
* @return {Promise} A promise which will be resolved when the modifications
* are complete.
*/
apply() {
return Promise.resolve(this.editPromise).then(() => {
return this.rule.setRuleText(this.result, this.modifications);
});
},
/**
* Get the result of the rewriting. This is used for testing.
*
* @return {object} an object of the form {changed: object, text: string}
* |changed| is an object where each key is
* the index of a property whose value had to be
* rewritten during the sanitization process, and
* whose value is the new text of the property.
* |text| is the rewritten text of the rule.
*/
getResult() {
return { changed: this.changedDeclarations, text: this.result };
},
};
/**
* Like trimRight, but only trims CSS-allowed whitespace.
*/
function cssTrimRight(str) {
const match = /^(.*?)[ \t\r\n\f]*$/.exec(str);
if (match) {
return match[1];
}
return str;
}
module.exports = RuleRewriter;