extension.js

"use strict";
const vscode = require("vscode");
const cp = require("child_process");
const path = require("path");

function findRegions(text) {
  const opener = /r(#+)"[ \t]*\/\*[ \t]*cpp[ \t]*\*\//g;
  const regions = [];
  let o;
  while ((o = opener.exec(text)) !== null) {
    const hashes = o[1];
    const innerStart = o.index + o[0].length;
    const close = '"' + hashes;
    const innerEnd = text.indexOf(close, innerStart);
    if (innerEnd === -1) continue;
    const lineStart = text.lastIndexOf("\n", o.index) + 1;
    const parentIndent = text.slice(lineStart, o.index).match(/^[ \t]*/)[0].length;
    regions.push({ innerStart, innerEnd, parentIndent });
    opener.lastIndex = innerEnd + close.length;
  }
  return regions;
}

function runClangFormat(input, cwd) {
  const res = cp.spawnSync("clang-format", ["-style=file"], {
    input,
    cwd,
    encoding: "utf8",
    maxBuffer: 64 * 1024 * 1024,
  });
  if (res.error) throw new Error("could not run clang-format: " + res.error.message);
  if (res.status !== 0) {
    throw new Error("clang-format exited " + res.status + ": " + (res.stderr || res.stdout).trim());
  }
  return res.stdout;
}

function indent(s, pad) {
  return s
    .split("\n")
    .map((l) => (l.trim() === "" ? "" : pad + l))
    .join("\n");
}

function stripCommonIndent(s) {
  let min = Infinity;
  for (const l of s.split("\n")) {
    if (l.trim() === "") continue;
    min = Math.min(min, l.match(/^[ \t]*/)[0].length);
  }
  if (!isFinite(min) || min === 0) return s;
  return s
    .split("\n")
    .map((l) => (l.trim() === "" ? l : l.slice(min)))
    .join("\n");
}

function computeEdits(doc) {
  const cwd = path.dirname(doc.uri.fsPath);
  const text = doc.getText();
  const edits = [];
  for (const r of findRegions(text)) {
    const inner = text.slice(r.innerStart, r.innerEnd);
    const normalized = stripCommonIndent(inner.replace(/^\n+/, "").replace(/\s+$/, ""));
    const body = runClangFormat(normalized, cwd).replace(/^\n+/, "").replace(/\s+$/, "");
    const bodyPad = " ".repeat(r.parentIndent + 4);
    const closerPad = " ".repeat(r.parentIndent);
    const out = "\n" + indent(body, bodyPad) + "\n" + closerPad;
    if (out === inner) continue;
    const range = new vscode.Range(doc.positionAt(r.innerStart), doc.positionAt(r.innerEnd));
    edits.push(vscode.TextEdit.replace(range, out));
  }
  return edits;
}

function activate(context) {
  context.subscriptions.push(
    vscode.workspace.onWillSaveTextDocument((e) => {
      if (e.document.languageId !== "rust") return;
      if (!vscode.workspace.getConfiguration("inlineCpp").get("formatOnSave")) return;
      e.waitUntil(
        (async () => {
          try {
            return computeEdits(e.document);
          } catch (err) {
            vscode.window.showErrorMessage("Inline C++: " + (err && err.message ? err.message : String(err)));
            return [];
          }
        })()
      );
    })
  );
}

function deactivate() {}

module.exports = { activate, deactivate };