Make the backpack persistent

We store the backpack in a new “user file” named backpack.xml (the other
user file supported is “android.keystore” for the user’s signing
key). As an optimization we remove the backpack.xml file if we store
“[]” in it (the empty backpack represented as an empty JSON string).

Change-Id: I16fb747f31e59d30535f690c1b35c80bde53629f

appinventor/appengine/src/com/google/appinventor/client/Ode.java

@@ -842,6 +842,20 @@ public void onFailure(Throwable caught) {
 
     userInfoService.getSystemConfig(sessionId, callback);
 
+    // We fetch the user's backpack here. This runs asynchronously with the rest
+    // of the system initialization.
+
+    userInfoService.getUserBackpack(new AsyncCallback<String>() {
+        @Override
+        public void onSuccess(String backpack) {
+          BlocklyPanel.setBackpack(backpack, false);
+        }
+        @Override
+        public void onFailure(Throwable caught) {
+          OdeLog.log("Fetching backpack failed");
+        }
+      });
+
     History.addValueChangeHandler(new ValueChangeHandler<String>() {
       @Override
       public void onValueChange(ValueChangeEvent<String> event) {

appinventor/appengine/src/com/google/appinventor/client/editor/youngandroid/BlocklyPanel.java

@@ -16,6 +16,7 @@
 import com.google.appinventor.client.editor.simple.SimpleComponentDatabase;
 import com.google.appinventor.client.explorer.project.ComponentDatabaseChangeListener;
 import com.google.appinventor.client.output.OdeLog;
+import com.google.gwt.user.client.rpc.AsyncCallback;
 import com.google.appinventor.components.common.YaVersion;
 
 import com.google.common.collect.Maps;
@@ -239,8 +240,21 @@ public static boolean blocksInited(String formName) {
   public static String getBackpack() {
     return backpack;
   }
-  public static void setBackpack(String bp_contents) {
+  public static void setBackpack(String bp_contents, boolean doStore) {
     backpack = bp_contents;
+    if (doStore) {
+      Ode.getInstance().getUserInfoService().storeUserBackpack(backpack,
+        new AsyncCallback<Void>() {
+          @Override
+          public void onSuccess(Void nothing) {
+            // Nothing to do...
+          }
+          @Override
+          public void onFailure(Throwable caught) {
+            OdeLog.elog("Failed setting the backpack");
+          }
+        });
+    }
   }
 
   /**
@@ -901,7 +915,7 @@ private static native void exportMethodsToJavascript() /*-{
     $wnd.BlocklyPanel_getBackpack =
       $entry(@com.google.appinventor.client.editor.youngandroid.BlocklyPanel::getBackpack());
     $wnd.BlocklyPanel_setBackpack =
-      $entry(@com.google.appinventor.client.editor.youngandroid.BlocklyPanel::setBackpack(Ljava/lang/String;));
+      $entry(@com.google.appinventor.client.editor.youngandroid.BlocklyPanel::setBackpack(Ljava/lang/String;Z));
   }-*/;
 
   private native void initJS() /*-{

appinventor/appengine/src/com/google/appinventor/server/UserInfoServiceImpl.java

@@ -12,6 +12,7 @@
 import com.google.appinventor.shared.rpc.user.Config;
 import com.google.appinventor.shared.rpc.user.User;
 import com.google.appinventor.shared.rpc.user.UserInfoService;
+import com.google.appinventor.shared.storage.StorageUtil;
 
 /**
  * Implementation of the user information service.
@@ -67,6 +68,20 @@ public Config getSystemConfig(String sessionId) {
     return config;
   }
 
+  /**
+   * Returns the user's backpack as an XML string.
+   *
+   * @return backpack
+   */
+  @Override
+  public String getUserBackpack() {
+    if (!hasUserFile(StorageUtil.USER_BACKPACK_FILENAME)) {
+      return "[]";
+    } else {
+      return storageIo.downloadUserFile(userInfoProvider.getUserId(), StorageUtil.USER_BACKPACK_FILENAME, "UTF-8");
+    }
+  }
+
   /**
    * Returns user information.
    *
@@ -108,6 +123,16 @@ public String loadUserSettings() {
     return storageIo.loadSettings(userInfoProvider.getUserId());
   }
 
+  /**
+   * Stores the user's backpack as an xml string
+   * @param backpack the xml string representing the backpack
+   */
+
+  @Override
+  public void storeUserBackpack(String backpack) {
+    storageIo.uploadUserFile(userInfoProvider.getUserId(), StorageUtil.USER_BACKPACK_FILENAME, backpack, "UTF-8");
+  }
+
   /**
    * Stores the user's settings.
    * @param settings  user's settings

appinventor/appengine/src/com/google/appinventor/server/storage/ObjectifyStorageIo.java

@@ -83,6 +83,7 @@
 import java.io.UnsupportedEncodingException;
 import java.nio.channels.Channels;
 import java.nio.ByteBuffer;
+import java.util.Arrays;
 import java.util.ArrayList;
 import java.util.ConcurrentModificationException;
 import java.util.List;
@@ -1225,12 +1226,35 @@ public void run(Objectify datastore) {
   }
 
   /*
-   * We expect the UserFileData object for the given userId and fileName to
-   * already exist in the datastore. Find the object and update its contents.
+   * We look for the UserFileData object for the given userId and fileName.
+   * If it doesn't exit, we create it.
+   *
+   * SPECIAL CASE: If fileName == StorageUtil.USER_BACKBACK_FILENAME and the
+   * content is "[]", we *delete* the file because the default value returned
+   * if the file doesn't exist is "[]" (the JSON empty list). This is to reduce
+   * the clutter of files for the case where someone doesn't have anything in
+   * the backpack. We pay $$ for storage.
+   *
    */
   private void addUserFileContents(Objectify datastore, String userId, String fileName, byte[] content) {
     UserFileData ufd = datastore.find(userFileKey(userKey(userId), fileName));
-    Preconditions.checkState(ufd != null);
+    byte [] empty = new byte[] { (byte)0x5b, (byte)0x5d }; // "[]" in bytes
+    if (ufd == null) {          // File doesn't exist
+      if (fileName.equals(StorageUtil.USER_BACKPACK_FILENAME) &&
+        Arrays.equals(empty, content)) {
+        return;                 // Nothing to do
+      }
+      ufd = new UserFileData();
+      ufd.fileName = fileName;
+      ufd.userKey = userKey(userId);
+    } else {
+      if (fileName.equals(StorageUtil.USER_BACKPACK_FILENAME) &&
+        Arrays.equals(empty, content)) {
+        // Storing an empty backback, just delete the file
+        datastore.delete(userFileKey(userKey(userId), fileName));
+        return;
+      }
+    }
     ufd.content = content;
     datastore.put(ufd);
   }

appinventor/appengine/src/com/google/appinventor/shared/rpc/user/UserInfoService.java

@@ -25,6 +25,13 @@ public interface UserInfoService extends RemoteService {
 
   Config getSystemConfig(String sessionId);
 
+  /**
+   * Retrieve's the stored Backpack
+   *
+   * @return the backpack as an xml string
+   */
+  String getUserBackpack();
+
   /**
    * Retrieves information about the current user
    *
@@ -48,6 +55,12 @@ public interface UserInfoService extends RemoteService {
    */
   String loadUserSettings();
 
+  /**
+   * Store the user's backpack
+   * @param backpack string containing the backpack xml
+   */
+  void storeUserBackpack(String backpack);
+
   /**
    * Stores the user's settings.
    * @param settings  user's settings

appinventor/appengine/src/com/google/appinventor/shared/rpc/user/UserInfoServiceAsync.java

@@ -21,6 +21,11 @@ public interface UserInfoServiceAsync {
    */
   void getSystemConfig(String sessionId, AsyncCallback<Config> callback);
 
+  /**
+   * @see UserInfoService#getUserBackpack()
+   */
+  void getUserBackpack(AsyncCallback<String> callback);
+
   /**
    * @see UserInfoService#getUserInformation()
    */
@@ -36,6 +41,11 @@ public interface UserInfoServiceAsync {
    */
   void loadUserSettings(AsyncCallback<String> callback);
 
+  /**
+   * @see UserInfoService#storeUserBackpack(String)
+   */
+  void storeUserBackpack(String backpack, AsyncCallback<Void> callback);
+
   /**
    * @see UserInfoService#storeUserSettings(String)
    */

appinventor/appengine/src/com/google/appinventor/shared/storage/StorageUtil.java

@@ -27,6 +27,7 @@ private StorageUtil() {}
   public static final long INITIAL_MOTD_ID = 1;
 
   public static final String ANDROID_KEYSTORE_FILENAME = "android.keystore";
+  public static final String USER_BACKPACK_FILENAME = "backpack.xml";
 
   /**
    * Gets the final component from a path.  This assumes that path components

appinventor/appengine/tests/com/google/appinventor/server/storage/ObjectifyStorageIoTest.java

@@ -211,25 +211,6 @@ public void testUploadBeforeAdd() throws BlocksTruncatedException {
     }
   }
 
-  public void testUploadUserFileBeforeAdd() {
-    final String USER_ID = "900";
-    final String USER_EMAIL = "[email protected]";
-    storage.getUser(USER_ID, USER_EMAIL);
-    try {
-      storage.uploadUserFile(USER_ID, FILE_NAME1, "does not matter",
-          StorageUtil.DEFAULT_CHARSET);
-      fail("Allowed upload before add");
-    } catch (IllegalStateException ignored) {
-      // File upload should be preceded by add
-    }
-    try {
-      storage.uploadRawUserFile(USER_ID, FILE_NAME2, "does not matter".getBytes());
-      fail("Allowed upload before add");
-    } catch (IllegalStateException ignored) {
-      // File upload should be preceded by add
-    }
-  }
-
   public void testMuliRoleFile() {
     final String USER_ID = "1000";
     final String USER_EMAIL = "[email protected]";

appinventor/blocklyeditor/src/backpack.js

@@ -290,18 +290,21 @@ Blockly.Backpack.prototype.addAllToBackpack = function() {
   var allBlocks = Blockly.mainWorkspace.getAllBlocks();
   var topBlocks = Blockly.mainWorkspace.getTopBlocks(false);
   for (var x = 0; x < topBlocks.length; x++) {
-      block = allBlocks[x];
-      this.addToBackpack(block);
+    block = allBlocks[x];
+    this.addToBackpack(block, false);
   }
+  // We have to read back the backpack (getBackpack) and store it again
+  // this time stating that it should be pushed up to the server
+  this.setBackpack(this.getBackpack(), true); // A little klunky but gets the job done
 }
 
 /**
  *  The backpack is an array containing 0 or more
  *   blocks
  */
-Blockly.Backpack.prototype.addToBackpack = function(block) {
+Blockly.Backpack.prototype.addToBackpack = function(block, store) {
   if (this.getBackpack() == undefined) {
-    this.setBackpack(JSON.stringify([]));
+    this.setBackpack(JSON.stringify([]), false);
   }
 
   // Copy is made of the expanded block.
@@ -321,7 +324,7 @@ Blockly.Backpack.prototype.addToBackpack = function(block) {
   var len = bp_contents.length;
   var newBlock = "<xml>" + Blockly.Xml.domToText(xmlBlock) + "</xml>";
   bp_contents[len] = newBlock;
-  this.setBackpack(JSON.stringify(bp_contents));
+  this.setBackpack(JSON.stringify(bp_contents), store);
   this.grow();
   Blockly.playAudio('backpack');
 
@@ -555,7 +558,7 @@ Blockly.Backpack.prototype.shrink = function() {
  */
 Blockly.Backpack.prototype.clear = function() {
   if (Blockly.mainWorkspace.backpack.confirmClear()) {
-    this.setBackpack(JSON.stringify([]));
+    this.setBackpack(JSON.stringify([]), true);
     this.shrink();
   }
 }
@@ -578,7 +581,7 @@ Blockly.Backpack.prototype.getBackpack = function() {
   return window.parent.BlocklyPanel_getBackpack();
 }
 
-Blockly.Backpack.prototype.setBackpack = function(backpack) {
-  window.parent.BlocklyPanel_setBackpack(backpack);
+Blockly.Backpack.prototype.setBackpack = function(backpack, store) {
+  window.parent.BlocklyPanel_setBackpack(backpack, store);
 }
 

appinventor/lib/blockly/src/core/block.js

@@ -702,7 +702,7 @@ Blockly.Block.prototype.onMouseUp_ = function(e) {
       var backpack = this_.workspace.backpack
 	//      var xy = this.getRelativeToSurfaceXY();
       goog.Timer.callOnce(backpack.close, 100, backpack);
-      backpack.addToBackpack(Blockly.selected);
+      backpack.addToBackpack(Blockly.selected, true);
       Blockly.mainWorkspace.backpack.onMouseUp(e, Blockly.selected.startDragMouseX, Blockly.selected.startDragMouseY);
     }
     if (Blockly.highlightedConnection_) {
@@ -858,7 +858,7 @@ Blockly.Block.prototype.showContextMenu_ = function(e) {
       callback: function() {
         if (Blockly.selected && Blockly.selected.isDeletable() &&
             Blockly.selected.workspace == Blockly.mainWorkspace) {
-          Blockly.mainWorkspace.backpack.addToBackpack(Blockly.selected);
+          Blockly.mainWorkspace.backpack.addToBackpack(Blockly.selected, true);
         }
       }
     };