46 lines
2.2 KiB
JavaScript
46 lines
2.2 KiB
JavaScript
// Hunk diffs for the DSH diff card ({path, oldText, newText} per hunk, 3 lines of context).
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// Each hunk also carries `oldStart`/`newStart` (1-based file lines of its first row) and `rows`
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// ([op, text] with op '=', '-', '+') so a client can draw a line-number gutter.
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import { lineMap } from './store.js'
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import { splitLines } from './text.js'
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export function hunkDiffs(path, before, after, context = 3) {
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const a = splitLines(before).lines
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const b = splitLines(after).lines
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const map = lineMap(a, b)
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// Walk both sides, emitting ops: '=' common, '-' removed, '+' added.
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const ops = [] // [op, text, oldLine|null, newLine|null]
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let i = 1; let j = 1
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const pairs = [...map.entries()].sort((x, y) => x[0] - y[0])
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for (const [ai, bj] of pairs) {
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while (i < ai) { ops.push(['-', a[i - 1], i, null]); i++ }
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while (j < bj) { ops.push(['+', b[j - 1], null, j]); j++ }
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ops.push(['=', a[i - 1], i, j]); i++; j++
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}
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while (i <= a.length) { ops.push(['-', a[i - 1], i, null]); i++ }
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while (j <= b.length) { ops.push(['+', b[j - 1], null, j]); j++ }
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const changed = ops.map((o, k) => (o[0] !== '=' ? k : -1)).filter((k) => k >= 0)
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if (!changed.length) return []
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const spans = []
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for (const k of changed) {
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const s = Math.max(0, k - context); const e = Math.min(ops.length - 1, k + context)
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const last = spans.at(-1)
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if (last && s <= last[1] + 1) last[1] = Math.max(last[1], e)
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else spans.push([s, e])
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}
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return spans.map(([s, e]) => {
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const oldL = []; const newL = []; const rows = []
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let oldStart = null; let newStart = null
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for (let k = s; k <= e; k++) {
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const [op, text, ol, nl] = ops[k]
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if (op !== '+') { oldL.push(text); oldStart ??= ol }
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if (op !== '-') { newL.push(text); newStart ??= nl }
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rows.push([op, text])
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}
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// A pure insertion/deletion side has no line of its own: anchor it next to its neighbour.
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oldStart ??= Math.max(1, (ops.slice(0, s).findLast((o) => o[2] !== null)?.[2] ?? 0) + 1)
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newStart ??= Math.max(1, (ops.slice(0, s).findLast((o) => o[3] !== null)?.[3] ?? 0) + 1)
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return { path, oldText: oldL.length ? oldL.join('\n') : null, newText: newL.join('\n'), oldStart, newStart, rows }
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})
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}
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