controlling QuotaError when localStorage is full

lib/edit/ISSUES.md

@@ -3,12 +3,13 @@
 	- adds: OK
 	- deletes: OK
 - change pushEdit() to pushEdits(), NO
+- control QuotaError error gracefully, ONGOING
 
 - try and fill localStorage to see what happens... OK, localStorage.setItem() throws error
-
-- goOnline()/goOffline() automatically
 - prevent attributeEditor to appear after replaying the stored edits
 - be careful with updates for features added offline (replace tmp id by final id)
+- goOnline()/goOffline() automatically
+
 - unit tests
 - feedback graphics layer
 - add timestamp to edits

lib/edit/editsStore.js

@@ -52,9 +52,10 @@ define(["esri/graphic"], function(Graphic)
 			else
 			{
 				edits.push(edit);
-				this._storeEditsQueue(edits);
-				this._storeRedoStack([]);
-				return true; // success
+				var success =
+					this._storeRedoStack([]) && 
+					this._storeEditsQueue(edits);
+				return success;
 			}
 		},
 
@@ -166,16 +167,16 @@ define(["esri/graphic"], function(Graphic)
 			var redoStack = this._retrieveRedoStack();
 			var editToRedo = redoStack.pop();
 			edits.push(editToRedo);
-			this._storeEditsQueue(edits);
 			this._storeRedoStack(redoStack);
+			this._storeEditsQueue(edits);
 
 			return editToRedo;
 		},
 
 		getEditsStoreSizeBytes: function()
 		{
-			return window.localStorage.getItem(EDITS_QUEUE_KEY).length +
-				window.localStorage.getItem(REDO_STACK_KEY).length; 
+			return EDITS_QUEUE_KEY.length + window.localStorage.getItem(EDITS_QUEUE_KEY).length +
+				REDO_STACK_KEY.length + window.localStorage.getItem(REDO_STACK_KEY).length; 
 
 		},
 
@@ -185,7 +186,7 @@ define(["esri/graphic"], function(Graphic)
 			for( var key in window.localStorage )
 			{
 				var value = window.localStorage.getItem(key);
-				bytes += value.length;
+				bytes += key.length + value.length;
 			}
 			return bytes;
 		},
@@ -225,9 +226,16 @@ define(["esri/graphic"], function(Graphic)
 
 		_storeEditsQueue: function(edits)
 		{
-			// jabadia: handle the QuotaExceeded error gracefully
-			var serializedEdits = this._packArrayOfEdits(edits);
-			window.localStorage.setItem(EDITS_QUEUE_KEY, serializedEdits);
+			try 
+			{
+				var serializedEdits = this._packArrayOfEdits(edits);
+				window.localStorage.setItem(EDITS_QUEUE_KEY, serializedEdits);
+				return true;
+			}
+			catch(err)
+			{
+				return false;
+			}
 		},
 
 		_retrieveRedoStack: function()
@@ -238,9 +246,16 @@ define(["esri/graphic"], function(Graphic)
 
 		_storeRedoStack: function(edits)
 		{
-			// jabadia: handle the QuotaExceeded error gracefully
-			var serializedEdits = this._packArrayOfEdits(edits);
-			window.localStorage.setItem(REDO_STACK_KEY, serializedEdits);
+			try
+			{
+				var serializedEdits = this._packArrayOfEdits(edits);
+				window.localStorage.setItem(REDO_STACK_KEY, serializedEdits);
+				return true;
+			}
+			catch(err)
+			{
+				return false;
+			}
 		},
 
 		_packArrayOfEdits: function(edits)

test/spec/editsStoreSpec.js

@@ -1,5 +1,8 @@
 "use strict"
 
+var KEY_PREFIX = "__LOCAL_STORAGE_TEST__";
+var EXECUTE_LONG_TESTS = true;
+
 describe("Internal Methods", function()
 {
 	describe("Serialize/Deserialize Graphics", function()
@@ -204,6 +207,12 @@ describe("Public Interface", function()
 		{
 			it("reset edits queue", function()
 			{
+				for( var key in window.localStorage )
+				{
+					if( key.indexOf(KEY_PREFIX)==0 )
+						window.localStorage.removeItem(key);
+				}
+
 				g_editsStore.resetEditsQueue();
 				expect(g_editsStore.pendingEditsCount()).toBe(0);
 			});
@@ -436,14 +445,59 @@ describe("Public Interface", function()
 		it("report edit store size", function()
 		{
 			usedBytes = g_editsStore.getEditsStoreSizeBytes();
-			expect(usedBytes).toBe(678);
+			expect(usedBytes).toBe(705);
 		});
 
 		it("report total local storage size", function()
 		{
 			totalBytes = g_editsStore.getLocalStorageSizeBytes();
 			expect(usedBytes).not.toBeGreaterThan(totalBytes);
-		})
+		});
+
+		it("exhaust localStorage capacity", function()
+		{
+			if( EXECUTE_LONG_TESTS )
+			{
+				console.log("this will take some time");
+
+				var sizeBefore = g_editsStore.getLocalStorageSizeBytes();
+
+				// first, fill localStorage up to max capacity
+				try
+				{
+					var index = 0;
+					var value = "0123456789";
+					var value8 = value + value + value + value + value + value + value + value;
+					while(true)
+					{
+						var key = KEY_PREFIX + index;
+						window.localStorage.setItem(key, value8 + value8 + value8 + value8);
+						index += 1;
+
+						if( index % 1000 == 0)
+							console.log(index, g_editsStore.getLocalStorageSizeBytes());
+					}				
+				}
+				catch(err)
+				{
+					console.log(err);
+				}
+
+				// now, try to push one edit
+				var success = g_editsStore.pushEdit(g_editsStore.ADD, 20, g_test.polygonFeature);
+				expect(success).toBeFalsy();
+
+				// clean everything
+				for( var key in window.localStorage )
+				{
+					if( key.indexOf(KEY_PREFIX)==0 )
+						window.localStorage.removeItem(key);
+				}
+
+				var sizeAfter = g_editsStore.getLocalStorageSizeBytes();
+				expect(sizeBefore).toEqual(sizeAfter);				
+			}
+		});
 	})
 });