From d955e5b1ee5cf93858d95160f9ee473193459df6 Mon Sep 17 00:00:00 2001
From: Stanislaw Adaszewski <s.adaszewski@gmail.com>
Date: Thu, 6 Feb 2020 07:37:23 +0100
Subject: [PATCH] Request ordering implemented and seems to be working but
 decreases responsiveness, perhaps better to manage ordering within
 components.

---
 .../src/js/component/wb-collection-listing.js |  3 +-
 frontend/src/js/misc/make-arvados-request.js  | 22 ++-----
 .../src/js/misc/wb-apply-request-ordering.js  | 66 +++++++++++++++++++
 3 files changed, 74 insertions(+), 17 deletions(-)
 create mode 100644 frontend/src/js/misc/wb-apply-request-ordering.js

diff --git a/frontend/src/js/component/wb-collection-listing.js b/frontend/src/js/component/wb-collection-listing.js
index a008878..0eeb5e6 100644
--- a/frontend/src/js/component/wb-collection-listing.js
+++ b/frontend/src/js/component/wb-collection-listing.js
@@ -66,8 +66,7 @@ class WBCollectionListing extends Component {
     let prom = makeArvadosRequest(arvHost, arvToken,
       '/arvados/v1/collections?filters=' + encodeURIComponent(JSON.stringify(filters)) +
       '&limit=' + encodeURIComponent(itemsPerPage) +
-      '&offset=' + encodeURIComponent(itemsPerPage * activePage),
-      { 'orderStream': this.state.orderStream });
+      '&offset=' + encodeURIComponent(itemsPerPage * activePage));
 
     let collections;
     let numPages
diff --git a/frontend/src/js/misc/make-arvados-request.js b/frontend/src/js/misc/make-arvados-request.js
index a285f08..0ce66a0 100644
--- a/frontend/src/js/misc/make-arvados-request.js
+++ b/frontend/src/js/misc/make-arvados-request.js
@@ -1,4 +1,4 @@
-const requestOrdering = {};
+import wbApplyRequestOrdering from 'wb-apply-request-ordering';
 
 function makeArvadosRequest(arvHost, arvToken, endpoint, params={}) {
   const defaultParams = {
@@ -7,22 +7,12 @@ function makeArvadosRequest(arvHost, arvToken, endpoint, params={}) {
     'contentType': 'application/json;charset=utf-8',
     'responseType': 'json',
     'useSsl': true,
-    'requireToken': true,
-    'orderStream': null
+    'requireToken': true
   };
 
   Object.keys(defaultParams).map(k => (params[k] =
     (k in params ? params[k] : defaultParams[k])));
-  let { method, data, contentType, responseType, useSsl, requireToken, orderStream } = params;
-
-  let orderId;
-  if (orderStream) {
-    if (!(orderStream in requestOrdering))
-      requestOrdering[orderStream] = { 'counter': 0, 'started': [], 'completed': [] };
-    requestOrdering[orderStream].counter += 1;
-    orderId = requestOrdering[orderStream].counter;
-    requestOrdering[orderStream].started.push(orderId);
-  }
+  let { method, data, contentType, responseType, useSsl, requireToken } = params;
 
   if (!(arvHost && (arvToken || !requireToken)))
     return new Promise((accept, reject) => reject());
@@ -35,7 +25,7 @@ function makeArvadosRequest(arvHost, arvToken, endpoint, params={}) {
     xhr.setRequestHeader('Content-Type', contentType);
   xhr.responseType = responseType;
 
-  let res = new Promise((accept, reject) => {
+  let prom = new Promise((accept, reject) => {
     xhr.onreadystatechange = () => {
       if (xhr.readyState !== 4)
         return;
@@ -47,7 +37,9 @@ function makeArvadosRequest(arvHost, arvToken, endpoint, params={}) {
     xhr.send(data);
   });
 
-  return res;
+  // prom = wbApplyRequestOrdering(prom);
+
+  return prom;
 }
 
 export default makeArvadosRequest;
diff --git a/frontend/src/js/misc/wb-apply-request-ordering.js b/frontend/src/js/misc/wb-apply-request-ordering.js
new file mode 100644
index 0000000..860fd77
--- /dev/null
+++ b/frontend/src/js/misc/wb-apply-request-ordering.js
@@ -0,0 +1,66 @@
+const defaultOrderRegistry = {};
+
+function wbApplyRequestOrdering(prom, orderRegistry) {
+  let orderId;
+
+  if (!orderRegistry)
+    orderRegistry = defaultOrderRegistry;
+
+  if (Object.keys(orderRegistry).length === 0) {
+    orderRegistry.started = 0;
+    orderRegistry.pendingCompletion = {};
+    orderRegistry.completed = { 0: true };
+  }
+
+  orderRegistry.started += 1;
+  orderId = orderRegistry.started;
+  // console.log('New orderId: ' + orderId);
+
+  const orderCallback = ((isCatch, payload) => {
+    // console.log('orderId: ' + orderId +
+    //  ', pendingCompletion: ' + Object.keys(orderRegistry.pendingCompletion) +
+    //  ', completed: ' + Object.keys(orderRegistry.completed));
+
+    if ((orderId - 1) in orderRegistry.completed) {
+      // console.log('Running: ' + orderId);
+      orderRegistry.completed[orderId] = true;
+      delete orderRegistry.pendingCompletion[orderId];
+
+      const keys = Object.keys(orderRegistry.pendingCompletion);
+      keys.sort((a, b) => (a - b));
+      keys.map(k => {
+        if ((k - 1) in orderRegistry.completed) {
+          // console.log('Running: ' + k);
+          orderRegistry.pendingCompletion[k]();
+          orderRegistry.completed[k] = true;
+          delete orderRegistry.pendingCompletion[k];
+        }
+      });
+
+      if (orderRegistry.started in orderRegistry.completed) {
+        // console.log('Garbage collect');
+        orderRegistry.started = 0;
+        orderRegistry.completed = { 0: true };
+      }
+
+      if (isCatch)
+        throw payload;
+      else
+        return payload;
+    }
+
+    const prom_1 = new Promise((accept, reject) => {
+      orderRegistry.pendingCompletion[orderId] = (() =>
+        (isCatch ? reject(payload) : accept(payload)));
+    });
+
+    return prom_1;
+  });
+
+  prom = prom.then(xhr => orderCallback(false, xhr));
+  prom = prom.catch(e => orderCallback(true, e));
+
+  return prom;
+}
+
+export default wbApplyRequestOrdering;