allow some operations to proceed in parallel

some code chunks previously used `async.parallel` but if you
use `await` that forces them to be run serially.  Instead,
you can initiate the operation (getting a Promise) and then
_later_ `await` the result of that Promise.

src/node/db/Pad.js

@@ -169,9 +169,8 @@ Pad.prototype.getInternalRevisionAText = async function getInternalRevisionAText
 
   // get all needed data out of the database
 
-  // get the atext of the key revision
-  let _atext = await db.getSub("pad:" + this.id + ":revs:" + keyRev, ["meta", "atext"]);
-  let atext = Changeset.cloneAText(_atext);
+  // start to get the atext of the key revision
+  let p_atext = db.getSub("pad:" + this.id + ":revs:" + keyRev, ["meta", "atext"]);
 
   // get all needed changesets
   let changesets = [];
@@ -181,6 +180,10 @@ Pad.prototype.getInternalRevisionAText = async function getInternalRevisionAText
     });
   }));
 
+  // we should have the atext by now
+  let atext = await p_atext;
+  atext = Changeset.cloneAText(atext);
+
   // apply all changesets to the key changeset
   let apool = this.apool();
   for (let curRev = keyRev; curRev < targetRev; ) {
@@ -455,7 +458,10 @@ Pad.prototype.remove = async function remove() {
   // kick everyone from this pad
   padMessageHandler.kickSessionsFromPad(padID);
 
-  // delete all relations
+  // delete all relations - the original code used async.parallel but
+  // none of the operations except getting the group depended on callbacks
+  // so the database operations here are just started and then left to
+  // run to completion
 
   // is it a group pad? -> delete the entry of this pad in the group
   if (padID.indexOf("$") >= 0) {

src/node/db/SecurityManager.js

@@ -49,11 +49,11 @@ exports.checkAccess = async function(padID, sessionCookie, token, password)
     return deny;
   }
 
-  // get author for this token
-  let tokenAuthor = await authorManager.getAuthor4Token(token);
+  // start to get author for this token
+  let p_tokenAuthor = authorManager.getAuthor4Token(token);
 
-  // check if pad exists
-  let padExists = await padManager.doesPadExist(padID);
+  // start to check if pad exists
+  let p_padExists = padManager.doesPadExist(padID);
 
   if (settings.requireSession) {
     // a valid session is required (api-only mode)
@@ -67,11 +67,14 @@ exports.checkAccess = async function(padID, sessionCookie, token, password)
       // it's not a group pad, means we can grant access
 
       // assume user has access
-      let statusObject = { accessStatus: "grant", authorID: tokenAuthor };
+      let authorID = await p_tokenAuthor;
+      let statusObject = { accessStatus: "grant", authorID };
 
       if (settings.editOnly) {
         // user can't create pads
 
+        let padExists = await p_padExists;
+
         if (!padExists) {
           // pad doesn't exist - user can't have access
           statusObject.accessStatus = "deny";
@@ -96,10 +99,13 @@ exports.checkAccess = async function(padID, sessionCookie, token, password)
     let sessionIDs = sessionCookie.split(',');
 
     // was previously iterated in parallel using async.forEach
-    for (let sessionID of sessionIDs) {
-      try {
-        let sessionInfo = await sessionManager.getSessionInfo(sessionID);
+    let sessionInfos = await Promise.all(sessionIDs.map(sessionID => {
+      return sessionManager.getSessionInfo(sessionID);
+    }));
 
+    // seperated out the iteration of sessioninfos from the (parallel) fetches from the DB
+    for (let sessionInfo of sessionInfos) {
+      try {
         // is it for this group?
         if (sessionInfo.groupID != groupID) {
           authLogger.debug("Auth failed: wrong group");
@@ -128,6 +134,8 @@ exports.checkAccess = async function(padID, sessionCookie, token, password)
     }
   }
 
+  let padExists = await p_padExists;
+
   if (padExists) {
     let pad = await padManager.getPad(padID);
 
@@ -205,7 +213,7 @@ exports.checkAccess = async function(padID, sessionCookie, token, password)
   if (!validSession && padExists) {
     // there is no valid session avaiable AND pad exists
 
-    let authorID = tokenAuthor;
+    let authorID = await p_tokenAuthor;
     let grant = Object.freeze({ accessStatus: "grant", authorID });
 
     if (isPublic && !isPasswordProtected) {

src/node/handler/PadMessageHandler.js

@@ -890,8 +890,6 @@ async function handleClientReady(client, message)
     return;
   }
 
-  var historicalAuthorData = {};
-
   hooks.callAll("clientReady", message);
 
   // Get ro/rw id:s
@@ -915,12 +913,12 @@ async function handleClientReady(client, message)
 
   let author = statusObject.authorID;
 
-  // get all authordata of this new user, and load the pad-object from the database
+  // get all authordata of this new user
   let value = await authorManager.getAuthor(author);
   let authorColorId = value.colorId;
   let authorName = value.name;
 
-  // get pad
+  // load the pad-object from the database
   let pad = await padManager.getPad(padIds.padId);
 
   // these db requests all need the pad object (timestamp of latest revision, author data)
@@ -930,6 +928,7 @@ async function handleClientReady(client, message)
   let currentTime = await pad.getRevisionDate(pad.getHeadRevisionNumber());
 
   // get all author data out of the database (in parallel)
+  let historicalAuthorData = {};
   await Promise.all(authors.map(authorId => {
     return authorManager.getAuthor(authorId).then(author => {
       if (!author) {
@@ -1010,12 +1009,15 @@ async function handleClientReady(client, message)
       changesets[r] = {};
     }
 
-    // get changesets, author and timestamp needed for pending revisions
+    // get changesets, author and timestamp needed for pending revisions (in parallel)
+    let promises = [];
     for (let revNum of revisionsNeeded) {
-       changesets[revNum]['changeset'] = await pad.getRevisionChangeset(revNum);
-       changesets[revNum]['author'] = await pad.getRevisionAuthor(revNum);
-       changesets[revNum]['timestamp'] = await pad.getRevisionDate(revNum);
+       let cs = changesets[revNum];
+       promises.push( pad.getRevisionChangeset(revNum).then(result => cs.changeset = result ));
+       promises.push(    pad.getRevisionAuthor(revNum).then(result => cs.author = result    ));
+       promises.push(      pad.getRevisionDate(revNum).then(result => cs.timestamp = result ));
     }
+    await Promise.all(promises);
 
     // return pending changesets
     for (let r of revisionsNeeded) {