assignment-terrible-editor/app/codemirror/src/line/utils_line.js

86 lines
2.5 KiB
JavaScript

import { indexOf } from "../util/misc.js"
// Find the line object corresponding to the given line number.
export function getLine(doc, n) {
n -= doc.first
if (n < 0 || n >= doc.size) throw new Error("There is no line " + (n + doc.first) + " in the document.")
let chunk = doc
while (!chunk.lines) {
for (let i = 0;; ++i) {
let child = chunk.children[i], sz = child.chunkSize()
if (n < sz) { chunk = child; break }
n -= sz
}
}
return chunk.lines[n]
}
// Get the part of a document between two positions, as an array of
// strings.
export function getBetween(doc, start, end) {
let out = [], n = start.line
doc.iter(start.line, end.line + 1, line => {
let text = line.text
if (n == end.line) text = text.slice(0, end.ch)
if (n == start.line) text = text.slice(start.ch)
out.push(text)
++n
})
return out
}
// Get the lines between from and to, as array of strings.
export function getLines(doc, from, to) {
let out = []
doc.iter(from, to, line => { out.push(line.text) }) // iter aborts when callback returns truthy value
return out
}
// Update the height of a line, propagating the height change
// upwards to parent nodes.
export function updateLineHeight(line, height) {
let diff = height - line.height
if (diff) for (let n = line; n; n = n.parent) n.height += diff
}
// Given a line object, find its line number by walking up through
// its parent links.
export function lineNo(line) {
if (line.parent == null) return null
let cur = line.parent, no = indexOf(cur.lines, line)
for (let chunk = cur.parent; chunk; cur = chunk, chunk = chunk.parent) {
for (let i = 0;; ++i) {
if (chunk.children[i] == cur) break
no += chunk.children[i].chunkSize()
}
}
return no + cur.first
}
// Find the line at the given vertical position, using the height
// information in the document tree.
export function lineAtHeight(chunk, h) {
let n = chunk.first
outer: do {
for (let i = 0; i < chunk.children.length; ++i) {
let child = chunk.children[i], ch = child.height
if (h < ch) { chunk = child; continue outer }
h -= ch
n += child.chunkSize()
}
return n
} while (!chunk.lines)
let i = 0
for (; i < chunk.lines.length; ++i) {
let line = chunk.lines[i], lh = line.height
if (h < lh) break
h -= lh
}
return n + i
}
export function isLine(doc, l) {return l >= doc.first && l < doc.first + doc.size}
export function lineNumberFor(options, i) {
return String(options.lineNumberFormatter(i + options.firstLineNumber))
}