//
// Keep versions of files in EECS 482 github repos
//
const vscode = require('vscode');
const os = require('os');
const fs = require('fs');
const path = require('path');
const crypto = require('crypto');
const child_process = require('child_process');
const version = 'vscode-20250930';
const minTimeInterval = 1; // minimum time between versions
const minTagInterval = 60; // minimum time between tags
const maxAge = 60*60; // maximum age of version482 file
const maxSize = 50*1024*1024; // maximum size of version482 file
const username = os.userInfo().username.replace(/[^a-zA-Z0-9]/g, "");
let hash = {}; // last hash value for each version file
let size = {}; // last size for each version file
let prior = {}; // prior contents for each file
let priorTime = {}; // last time each file was written
let priorTag = {}; // last time each repo was tagged
let sessionStart = time();
let hashInitial = crypto.createHash('sha256').update(username + ' ' + sessionStart.toString());
let versionDir = {}; // .version482 directory name for each source file directory
let timer = {};
exports.activate = () => {
vscode.workspace.textDocuments.forEach(doc => initFile(doc));
vscode.workspace.onDidOpenTextDocument(doc => {
initFile(doc);
});
vscode.workspace.onDidSaveTextDocument(doc => {
textChanged(doc);
createEditTag(doc);
});
vscode.workspace.onDidChangeTextDocument(e => {
textChanged(e.document);
});
}
// return current time in seconds
function time() {
return(Math.trunc(Date.now()/1000));
}
// See if directory is in an EECS 482 git repo.
// Store .version482 directory name in versionDir, creating the .version482
// directory if needed. If the directory isn't in a git repo, then set
// the versionDir entry to the empty string.
function initVersionDir(dir) {
if (! (dir in versionDir)) {
let dirFound = "";
if (fs.existsSync(dir)) {
dirFound = dir;
} else {
// Windows VS Code may prepend extra directory components when WSL
// files are opened as local files). Fix this by removing directory
// components from the beginning of the directory name until I find a
// directory that exists.
// Parse the directory name into components.
let dirRoot = dir;
let dirRootLast;
let basename = "";
let components = [];
do {
dirRootLast = dirRoot;
basename = path.basename(dirRoot);
if (basename != "") {
components.unshift(basename);
dirRoot = path.dirname(dirRoot);
}
} while (basename != "" && dirRoot != dirRootLast);
// Look for the directory, removing prefixes if needed.
for (let i=0; i<components.length && dirFound == ""; i++) {
const dir1 = dirRoot + components.slice(i).join(path.sep);
if (fs.existsSync(dir1)) {
dirFound = dir1;
}
}
}
if (dirFound == "") {
versionDir[dir] = '';
} else {
try {
const stdout = child_process.execSync('cd "' + dirFound + '"; git remote -v 2> /dev/null');
if (stdout.indexOf('eecs482') < 0) {
// not in an EECS 482 repo
versionDir[dir] = '';
} else {
// this will throw an exception if git rev-parse fails,
// e.g., if the directory is not in a work tree
versionDir[dir] = child_process.execSync('cd "' + dirFound + '"; git rev-parse --show-toplevel').toString().trimEnd() + path.sep + '.version482';
// create the .version482 directory if needed
try {
if (! fs.statSync(versionDir[dir]).isDirectory) {
versionDir[dir] = '';
}
} catch (err) {
fs.mkdirSync(versionDir[dir]);
}
}
} catch (err) {
versionDir[dir] = '';
}
}
}
}
function initFile(doc) {
initVersionDir(path.dirname(doc.fileName));
}
function textChanged(doc) {
const now = time();
// Limit the rate of versioning events. Also save events where time has
// gone backward by more than minTimeInterval.
if (doc.fileName in priorTime
&& Math.abs(now - priorTime[doc.fileName]) < minTimeInterval) {
// replace any pending timer event for this file, so events don't pile up
if (doc.fileName in timer) {
clearTimeout(timer[doc.fileName]);
}
// make sure this version is eventually saved
timer[doc.fileName] = setTimeout(textChanged, minTimeInterval*1000, doc);
return;
}
initVersionDir(path.dirname(doc.fileName));
// make sure file is in an EECS 482 git repo
if (versionDir[path.dirname(doc.fileName)] == '') {
return;
}
// make sure file is a program source file, i.e., has extension {cpp,cc,h,hpp,py}
const ext = path.extname(doc.fileName);
if (ext != '.cpp' && ext != '.cc' && ext != '.h' && ext != '.hpp' && ext != '.py') {
return;
}
// make sure file isn't too big
if (doc.getText().length > 10 * 1024 * 1024) {
return;
}
const versionDirname = versionDir[path.dirname(doc.fileName)];
// check if version file has grown too old or too big
if (now - sessionStart > maxAge || (versionDirname in size && size[versionDirname] > maxSize)) {
// start new version file by mimicking restarting vscode
hash = {};
size = {};
prior = {};
priorTime = {};
sessionStart = now;
hashInitial = crypto.createHash('sha256').update(username + ' ' + sessionStart.toString());
}
if (! (versionDirname in hash)) {
hash[versionDirname] = hashInitial.copy();
}
if (! (versionDirname in size)) {
size[versionDirname] = 0;
}
const priorName = versionDirname + path.sep + sessionStart.toString() + '.' + username + '.prior';
const currentName = versionDirname + path.sep + sessionStart.toString() + '.' + username + '.current';
if (! (doc.fileName in prior)) {
prior[doc.fileName] = '';
}
fs.writeFileSync(priorName, prior[doc.fileName]);
const current = doc.getText();
fs.writeFileSync(currentName, current);
const versionfile = versionDirname + path.sep + sessionStart.toString() + '.' + username;
const diff = child_process.execSync('diff "' + priorName + '" "' + currentName + '"; rm "' + priorName + '" "' + currentName + '"').toString();
let dict = {};
dict['file'] = doc.fileName;
dict['diff'] = diff;
const line = version + ' ' + now + ' '
+ size[versionDirname] + ' '
+ hash[versionDirname].copy().digest('hex') + ' '
+ JSON.stringify(dict);
try {
fs.appendFileSync(versionfile, line + "\n", () => {});
} catch (err) {
return;
}
prior[doc.fileName] = current;
priorTime[doc.fileName] = now;
hash[versionDirname] = crypto.createHash('sha256').update(line);
size[versionDirname] += line.length + 1;
}
// try to create edit tag and push it to github
function createEditTag(doc) {
const now = time();
initVersionDir(path.dirname(doc.fileName));
// make sure file is in an EECS 482 git repo
if (versionDir[path.dirname(doc.fileName)] == '') {
return;
}
const versionDirname = versionDir[path.dirname(doc.fileName)];
// limit the rate of tagging
if (versionDirname in priorTag
&& now - priorTag[versionDirname] < minTagInterval) {
// make sure this event is eventually tagged
timer[versionDirname] = setTimeout(createEditTag,
(minTagInterval-(now-priorTag[versionDirname]))*1000, doc);
return;
}
const d = new Intl.DateTimeFormat("en-US",
{
timeZone: 'America/Detroit',
year: 'numeric',
month: '2-digit',
day: '2-digit',
hourCycle: 'h23',
hour: 'numeric',
minute: 'numeric',
second: 'numeric',
}).format(new Date);
const found = d.match(/(\d+)\/(\d+)\/(\d+)\D+(\d+)\D+(\d+)\D+(\d+)/);
const dateString = found[3] + '.' + found[1] + '.' + found[2] + '_' + found[4] + '.' + found[5] + '.' + found[6];
// Make sure this git repository has at least one commit, so HEAD~ refers
// to something when undoing the first temporary commit
try {
child_process.execSync('cd "' + versionDirname + '"; git log > /dev/null 2>&1');
} catch (err) {
child_process.execSync('cd "' + versionDirname + '"; git commit -m "initial commit" --allow-empty > /dev/null 2>&1');
}
// create first temporary commit
try {
child_process.execSync('cd "' + versionDirname + '"; git commit -m edit-' + dateString + '-tmp1 --allow-empty > /dev/null 2>&1');
// add version files to repo (only for the second temporary commit)
child_process.execSync('cd "' + versionDirname + '"; git add -f . > /dev/null 2>&1');
// create second temporary commit
try {
child_process.execSync('cd "' + versionDirname + '"; git commit -am edit-' + dateString + '-tmp2 --allow-empty > /dev/null 2>&1');
// create edit tag for the second temporary commit
try {
child_process.execSync('cd "' + versionDirname + '"; git tag -a edit-' + dateString + ' -m "" > /dev/null 2>&1');
priorTag[versionDirname] = now;
// remove version482 files that are guaranteed not to change
for (const f of fs.globSync(versionDirname + path.sep + "*")) {
if (now - path.basename(f).replace(/\..*/, '') > maxAge) {
fs.unlink(f, () => {});
}
}
} catch (err) {
// edit tag failed
}
// Undo second temporary commit. Use --mixed to unstage the files
// that were staged because of the -a argument to git commit
child_process.execSync('cd "' + versionDirname + '"; git reset --mixed HEAD~ > /dev/null 2>&1');
} catch (err) {
// second temporary commit failed
}
// Undo first temporary commit. Use --soft to preserve the files that
// that were already staged.
child_process.execSync('cd "' + versionDirname + '"; git reset --soft HEAD~ > /dev/null 2>&1');
} catch (err) {
// first temporary commit failed
}
// push tags
child_process.execSync('export SSH_ASKPASS=echo; export SSH_ASKPASS_REQUIRE=force; cd "' + versionDirname + '"; git push --tags --quiet > /dev/null 2>&1 &');
}
