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