102 lines
3 KiB
JavaScript
102 lines
3 KiB
JavaScript
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'use strict';
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var common = require('./common');
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// get snippet for a single line, respecting maxLength
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function getLine(buffer, lineStart, lineEnd, position, maxLineLength) {
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var head = '';
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var tail = '';
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var maxHalfLength = Math.floor(maxLineLength / 2) - 1;
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if (position - lineStart > maxHalfLength) {
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head = ' ... ';
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lineStart = position - maxHalfLength + head.length;
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}
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if (lineEnd - position > maxHalfLength) {
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tail = ' ...';
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lineEnd = position + maxHalfLength - tail.length;
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}
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return {
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str: head + buffer.slice(lineStart, lineEnd).replace(/\t/g, '→') + tail,
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pos: position - lineStart + head.length // relative position
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};
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}
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function padStart(string, max) {
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return common.repeat(' ', max - string.length) + string;
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}
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function makeSnippet(mark, options) {
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options = Object.create(options || null);
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if (!mark.buffer) return null;
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if (!options.maxLength) options.maxLength = 79;
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if (typeof options.indent !== 'number') options.indent = 1;
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if (typeof options.linesBefore !== 'number') options.linesBefore = 3;
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if (typeof options.linesAfter !== 'number') options.linesAfter = 2;
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var re = /\r?\n|\r|\0/g;
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var lineStarts = [ 0 ];
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var lineEnds = [];
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var match;
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var foundLineNo = -1;
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while ((match = re.exec(mark.buffer))) {
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lineEnds.push(match.index);
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lineStarts.push(match.index + match[0].length);
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if (mark.position <= match.index && foundLineNo < 0) {
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foundLineNo = lineStarts.length - 2;
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}
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}
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if (foundLineNo < 0) foundLineNo = lineStarts.length - 1;
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var result = '', i, line;
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var lineNoLength = Math.min(mark.line + options.linesAfter, lineEnds.length).toString().length;
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var maxLineLength = options.maxLength - (options.indent + lineNoLength + 3);
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for (i = 1; i <= options.linesBefore; i++) {
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if (foundLineNo - i < 0) break;
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line = getLine(
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mark.buffer,
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lineStarts[foundLineNo - i],
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lineEnds[foundLineNo - i],
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mark.position - (lineStarts[foundLineNo] - lineStarts[foundLineNo - i]),
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maxLineLength
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);
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result = common.repeat(' ', options.indent) + padStart((mark.line - i + 1).toString(), lineNoLength) +
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' | ' + line.str + '\n' + result;
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}
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line = getLine(mark.buffer, lineStarts[foundLineNo], lineEnds[foundLineNo], mark.position, maxLineLength);
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result += common.repeat(' ', options.indent) + padStart((mark.line + 1).toString(), lineNoLength) +
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' | ' + line.str + '\n';
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result += common.repeat('-', options.indent + lineNoLength + 3 + line.pos) + '^' + '\n';
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for (i = 1; i <= options.linesAfter; i++) {
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if (foundLineNo + i >= lineEnds.length) break;
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line = getLine(
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mark.buffer,
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lineStarts[foundLineNo + i],
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lineEnds[foundLineNo + i],
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mark.position - (lineStarts[foundLineNo] - lineStarts[foundLineNo + i]),
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maxLineLength
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);
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result += common.repeat(' ', options.indent) + padStart((mark.line + i + 1).toString(), lineNoLength) +
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' | ' + line.str + '\n';
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}
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return result.replace(/\n$/, '');
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}
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module.exports = makeSnippet;
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