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Simplify dom text scanner (#453)
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* Remove "enum" from name, update comment

* Simplify
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@toasted-nutbread
toasted-nutbread authored Dec 29, 2023
1 parent 580983b commit 476d754
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Showing 2 changed files with 81 additions and 143 deletions.
199 changes: 75 additions & 124 deletions ext/js/dom/dom-text-scanner.js
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Original file line number Diff line number Diff line change
Expand Up @@ -169,34 +169,16 @@ export class DOMTextScanner {
const nodeValue = /** @type {string} */ (textNode.nodeValue);
const nodeValueLength = nodeValue.length;
const {preserveNewlines, preserveWhitespace} = this._getWhitespaceSettings(textNode);
if (resetOffset) { this._offset = 0; }

let done = false;
let lineHasWhitespace = this._lineHasWhitespace;
let lineHasContent = this._lineHasContent;
let content = this._content;
let offset = resetOffset ? 0 : this._offset;
let remainder = this._remainder;
let newlines = this._newlines;

while (offset < nodeValueLength) {
const char = StringUtil.readCodePointsForward(nodeValue, offset, 1);
offset += char.length;
while (this._offset < nodeValueLength) {
const char = StringUtil.readCodePointsForward(nodeValue, this._offset, 1);
this._offset += char.length;
const charAttributes = DOMTextScanner.getCharacterAttributes(char, preserveNewlines, preserveWhitespace);
/** @type {import('dom-text-scanner').SeekTextNoteDetails} */
const seekTextNoteDetails = {done, lineHasWhitespace, lineHasContent, content, offset, remainder, newlines};

({done, lineHasWhitespace, lineHasContent, content, offset, remainder, newlines} = this._checkCharacterForward(char, charAttributes, seekTextNoteDetails));
if (done) { break; }
if (this._checkCharacterForward(char, charAttributes)) { break; }
}

this._lineHasWhitespace = lineHasWhitespace;
this._lineHasContent = lineHasContent;
this._content = content;
this._offset = offset;
this._remainder = remainder;
this._newlines = newlines;

return (remainder > 0);
return this._remainder > 0;
}

/**
Expand All @@ -216,35 +198,16 @@ export class DOMTextScanner {
const nodeValue = /** @type {string} */ (textNode.nodeValue);
const nodeValueLength = nodeValue.length;
const {preserveNewlines, preserveWhitespace} = this._getWhitespaceSettings(textNode);
if (resetOffset) { this._offset = nodeValueLength; }

let done = false;
let lineHasWhitespace = this._lineHasWhitespace;
let lineHasContent = this._lineHasContent;
let content = this._content;
let offset = resetOffset ? nodeValueLength : this._offset;
let remainder = this._remainder;
let newlines = this._newlines;

while (offset > 0) {
const char = StringUtil.readCodePointsBackward(nodeValue, offset - 1, 1);
offset -= char.length;
while (this._offset > 0) {
const char = StringUtil.readCodePointsBackward(nodeValue, this._offset - 1, 1);
this._offset -= char.length;
const charAttributes = DOMTextScanner.getCharacterAttributes(char, preserveNewlines, preserveWhitespace);

/** @type {import('dom-text-scanner').SeekTextNoteDetails} */
const seekTextNoteDetails = {done, lineHasWhitespace, lineHasContent, content, offset, remainder, newlines};

({done, lineHasWhitespace, lineHasContent, content, offset, remainder, newlines} = this._checkCharacterBackward(char, charAttributes, seekTextNoteDetails));
if (done) { break; }
if (this._checkCharacterBackward(char, charAttributes)) { break; }
}

this._lineHasWhitespace = lineHasWhitespace;
this._lineHasContent = lineHasContent;
this._content = content;
this._offset = offset;
this._remainder = remainder;
this._newlines = newlines;

return (remainder > 0);
return this._remainder > 0;
}

/**
Expand Down Expand Up @@ -275,126 +238,114 @@ export class DOMTextScanner {

/**
* @param {string} char
* @param {import('dom-text-scanner').CharacterAttributesEnum} charAttributes
* @param {import('dom-text-scanner').SeekTextNoteDetails} seekTextNoteDetails
* @returns {import('dom-text-scanner').SeekTextNoteDetails}
* @param {import('dom-text-scanner').CharacterAttributes} charAttributes
* @returns {boolean}
*/
_checkCharacterForward(char, charAttributes, seekTextNoteDetails) {
let {done, lineHasWhitespace, lineHasContent, content, offset, remainder, newlines} = seekTextNoteDetails;

_checkCharacterForward(char, charAttributes) {
switch (charAttributes) {
case 0:
break;
// case 0: break; // NOP
case 1:
lineHasWhitespace = true;
this._lineHasWhitespace = true;
break;
case 2:
case 3:
if (newlines > 0) {
if (content.length > 0) {
const useNewlineCount = Math.min(remainder, newlines);
content += '\n'.repeat(useNewlineCount);
remainder -= useNewlineCount;
newlines -= useNewlineCount;
if (this._newlines > 0) {
if (this._content.length > 0) {
const useNewlineCount = Math.min(this._remainder, this._newlines);
this._content += '\n'.repeat(useNewlineCount);
this._remainder -= useNewlineCount;
this._newlines -= useNewlineCount;
} else {
newlines = 0;
this._newlines = 0;
}
lineHasContent = false;
lineHasWhitespace = false;
if (remainder <= 0) {
offset -= char.length; // Revert character offset
done = true;
break;
this._lineHasContent = false;
this._lineHasWhitespace = false;
if (this._remainder <= 0) {
this._offset -= char.length; // Revert character offset
return true;
}
}

lineHasContent = (charAttributes === 2); // 3 = character is a newline
this._lineHasContent = (charAttributes === 2); // 3 = character is a newline

if (lineHasWhitespace) {
if (lineHasContent) {
content += ' ';
lineHasWhitespace = false;
if (--remainder <= 0) {
offset -= char.length; // Revert character offset
done = true;
break;
if (this._lineHasWhitespace) {
if (this._lineHasContent) {
this._content += ' ';
this._lineHasWhitespace = false;
if (--this._remainder <= 0) {
this._offset -= char.length; // Revert character offset
return true;
}
} else {
lineHasWhitespace = false;
this._lineHasWhitespace = false;
}
}

content += char;
this._content += char;

if (--remainder <= 0) {
done = true;
break;
if (--this._remainder <= 0) {
return true;
}
break;
}

return {done, lineHasWhitespace, lineHasContent, content, offset, remainder, newlines};
return false;
}

/**
* @param {string} char
* @param {import('dom-text-scanner').CharacterAttributesEnum} charAttributes
* @param {import('dom-text-scanner').SeekTextNoteDetails} seekTextNoteDetails
* @returns {import('dom-text-scanner').SeekTextNoteDetails}
* @param {import('dom-text-scanner').CharacterAttributes} charAttributes
* @returns {boolean}
*/
_checkCharacterBackward(char, charAttributes, seekTextNoteDetails) {
let {done, lineHasWhitespace, lineHasContent, content, offset, remainder, newlines} = seekTextNoteDetails;

_checkCharacterBackward(char, charAttributes) {
switch (charAttributes) {
case 0:
break;
// case 0: break; // NOP
case 1:
lineHasWhitespace = true;
this._lineHasWhitespace = true;
break;
case 2:
case 3:
if (newlines > 0) {
if (content.length > 0) {
const useNewlineCount = Math.min(remainder, newlines);
content = '\n'.repeat(useNewlineCount) + content;
remainder -= useNewlineCount;
newlines -= useNewlineCount;
if (this._newlines > 0) {
if (this._content.length > 0) {
const useNewlineCount = Math.min(this._remainder, this._newlines);
this._content = '\n'.repeat(useNewlineCount) + this._content;
this._remainder -= useNewlineCount;
this._newlines -= useNewlineCount;
} else {
newlines = 0;
this._newlines = 0;
}
lineHasContent = false;
lineHasWhitespace = false;
if (remainder <= 0) {
offset += char.length; // Revert character offset
done = true;
break;
this._lineHasContent = false;
this._lineHasWhitespace = false;
if (this._remainder <= 0) {
this._offset += char.length; // Revert character offset
return true;
}
}

lineHasContent = (charAttributes === 2); // 3 = character is a newline
this._lineHasContent = (charAttributes === 2); // 3 = character is a newline

if (lineHasWhitespace) {
if (lineHasContent) {
content = ' ' + content;
lineHasWhitespace = false;
if (--remainder <= 0) {
offset += char.length; // Revert character offset
done = true;
break;
if (this._lineHasWhitespace) {
if (this._lineHasContent) {
this._content = ' ' + this._content;
this._lineHasWhitespace = false;
if (--this._remainder <= 0) {
this._offset += char.length; // Revert character offset
return true;
}
} else {
lineHasWhitespace = false;
this._lineHasWhitespace = false;
}
}

content = char + content;
this._content = char + this._content;

if (--remainder <= 0) {
done = true;
break;
if (--this._remainder <= 0) {
return true;
}
break;
}

return {done, lineHasWhitespace, lineHasContent, content, offset, remainder, newlines};
return false;
}

// Static helpers
Expand Down Expand Up @@ -515,7 +466,7 @@ export class DOMTextScanner {
* @param {string} character A string containing a single character.
* @param {boolean} preserveNewlines Whether or not newlines should be preserved.
* @param {boolean} preserveWhitespace Whether or not whitespace should be preserved.
* @returns {import('dom-text-scanner').CharacterAttributesEnum} An enum representing the attributes of the character.
* @returns {import('dom-text-scanner').CharacterAttributes} An enum representing the attributes of the character.
*/
static getCharacterAttributes(character, preserveNewlines, preserveWhitespace) {
switch (character.charCodeAt(0)) {
Expand Down
25 changes: 6 additions & 19 deletions types/ext/dom-text-scanner.d.ts
View file
Original file line number Diff line number Diff line change
Expand Up @@ -17,23 +17,10 @@

/**
* An enum representing the attributes of the character.
*
* `0` Character should be ignored.
*
* `1` Character is collapsible whitespace.
*
* `2` Character should be added to the content.
*
* `3` Character should be added to the content and is a newline.
* This enum is a number enum for more efficient usage in a highly-traversed code path.
* - `0` - Character should be ignored.
* - `1` - Character is collapsible whitespace.
* - `2` - Character should be added to the content.
* - `3` - Character should be added to the content and is a newline.
*/
export type CharacterAttributesEnum = 0 | 1 | 2 | 3;

export type SeekTextNoteDetails = {
done: boolean;
lineHasWhitespace: boolean;
lineHasContent: boolean;
content: string;
offset: number;
remainder: number;
newlines: number;
};
export type CharacterAttributes = 0 | 1 | 2 | 3;

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