[renderjs_ui] Add non-recursive locking for gadgets into gadget_global

/reviewed-on nexedi/erp5!536

bt5/erp5_web_renderjs_ui/PathTemplateItem/web_page_module/rjs_gadget_global_js.js

@@ -126,4 +126,115 @@
       });
   };
 
+  /** Internal function to prepare gadget to hold a mutex */
+  function ensureLockable(gadget) {
+    if (gadget.props === undefined) {
+      gadget.props = {};
+    }
+    // waiting_line is container of mutexes which already blocks some Promise
+    if (gadget.props.waiting_line === undefined) {
+      gadget.props.waiting_line = [];
+    }
+  }
+
+  /** Synchronously lock gadget and return previous lock's promise.
+
+  NON-RECURSIVE lock! If you lock inside locked execution you will wait forever.
+
+  If used in a Queue (@see lockGadgetInQueue) it blocks when acquiring the lock.
+  */
+  window.lockGadget = function (gadget) {
+    var ahead_of_me;
+    ensureLockable(gadget);
+    // step in line
+    gadget.props.waiting_line.push(RSVP.defer());
+
+    if (gadget.props.waiting_line.length >= 2) {
+      // wait for the promise ahead of me
+      ahead_of_me = gadget.props.waiting_line[gadget.props.waiting_line.length - 2].promise;
+    } else {
+      ahead_of_me = RSVP.resolve();
+    }
+    // return previous lock's Promise to postpone execution
+    return ahead_of_me;
+  };
+
+  /** Lock gadget as a step in RSVP.Queue waiting for previous lock to unlock.
+
+  Use in RSVP.Queue to block execution until manually called `unlockGadget`.
+  Both lock/unlockGadget pass through any value in RSVP.Queue manner.
+  Pass through any value.
+
+  Example:
+    new RSVP.Queue()
+      .push(function () {return some_value;})
+      .push(lockGadgetInQueue(gadget), lockGadgetInFailedQueue(gadget))
+      .push(function (some_value) {return someWork(some_value);})
+      .push(unlockGadgetInQueue(gadget), unlockGadgetInFailedQueue(gadget));
+  */
+  window.lockGadgetInQueue = function (gadget) {
+    // return function to be used in RSVP.Queue
+    return function (pass_through) {
+      return new RSVP.Queue()
+        .push(function () {
+          return window.lockGadget(gadget);
+        })
+        .push(function () {
+          return pass_through;
+        });
+    };
+  };
+  /** Lock Gagdet in Queue but intended to be used in "fail" branch (the second function).
+
+  Rethrows any argument.
+  */
+  window.lockGadgetInFailedQueue = function (gadget) {
+    // return function to be used in RSVP.Queue
+    return function (error) {
+      return new RSVP.Queue()
+        .push(function () {
+          return window.lockGadget(gadget);
+        })
+        .push(function () {
+          throw error;
+        });
+    };
+  };
+
+  /** Synchronously unlock gadget by resolving props.mutex.promise.
+
+  That promise is most likely blocking some RSVP.Queue or is then-ed on another
+  Promise.
+  */
+  window.unlockGadget = function (gadget) {
+    if (gadget.props === undefined ||
+        gadget.props.waiting_line === undefined ||
+        gadget.props.waiting_line.length === 0) {
+      throw new Error("Gadget " + gadget + " is not locked!");
+    }
+    gadget.props.waiting_line.shift().resolve();
+  };
+
+  /** Unlock gadget without blocking as a step in RSVP.Queue.
+
+  Pass through any value. Not re-throwing errors in fail branch!
+
+  For example @see lockGadgetInQueue.
+  */
+  window.unlockGadgetInQueue = function (gadget) {
+    return function (pass_through) {
+      window.unlockGadget(gadget);
+      return pass_through;
+    };
+  };
+
+  /** Unlock gadget without blocking and throw any argument received. */
+  window.unlockGadgetInFailedQueue = function (gadget) {
+    return function (error) {
+      window.unlockGadget(gadget);
+      throw error;
+    };
+  };
+
+
 }(window, RSVP, FileReader));
\ No newline at end of file

bt5/erp5_web_renderjs_ui/PathTemplateItem/web_page_module/rjs_gadget_global_js.xml

@@ -230,7 +230,7 @@
             </item>
             <item>
                 <key> <string>serial</string> </key>
-                <value> <string>947.51167.64410.14796</string> </value>
+                <value> <string>964.19771.1861.12424</string> </value>
             </item>
             <item>
                 <key> <string>state</string> </key>
@@ -248,7 +248,7 @@
                     </tuple>
                     <state>
                       <tuple>
-                        <float>1450099422.01</float>
+                        <float>1513956134.36</float>
                         <string>UTC</string>
                       </tuple>
                     </state>