harden clearChannel implementation

This commit is contained in:
ansuz 2017-07-13 17:28:07 +02:00
parent 7be1e249e1
commit b295aaa6c7
1 changed files with 15 additions and 7 deletions

View File

@ -56,9 +56,9 @@ var closeChannel = function (env, channelName, cb) {
}
};
var clearChannel = function (Env, channelId, cb) {
var path = mkPath(Env, channelId);
getMetadataAtPath(Env, path, function (e, metadata) {
var clearChannel = function (env, channelId, cb) {
var path = mkPath(env, channelId);
getMetadataAtPath(env, path, function (e, metadata) {
if (e) { return cb(e); }
if (!metadata) {
return void Fs.truncate(path, 0, function (err) {
@ -70,9 +70,17 @@ var clearChannel = function (Env, channelId, cb) {
}
var len = JSON.stringify(metadata).length + 1;
Fs.truncate(path, len, function (err) {
if (err) { return cb(err); }
closeChannel(Env, channelId, cb);
// as long as closeChannel is synchronous, this should not cause
// any race conditions. truncate ought to return faster than a channel
// can be opened and read by another user. if that turns out not to be
// the case, we'll need to implement locking.
closeChannel(env, channelId, function (err) {
if (err) { cb(err); }
Fs.truncate(path, len, function (err) {
if (err) { return cb(err); }
cb();
});
});
});
};
@ -120,7 +128,7 @@ var checkPath = function (path, callback) {
};
var removeChannel = function (env, channelName, cb) {
var filename = Path.join(env.root, channelName.slice(0, 2), channelName + '.ndjson');
var filename = mkPath(env, channelName);
Fs.unlink(filename, cb);
};