Save most recent 3 destinations across multiple sessions

chrome/browser/resources/print_preview/data/app_state.js

Index: chrome/browser/resources/print_preview/data/app_state.js
diff --git a/chrome/browser/resources/print_preview/data/app_state.js b/chrome/browser/resources/print_preview/data/app_state.js
index b782f4ea3d1543fc1b8edb23ba6fdb842778570c..68688c9e42ddecdabb50a29c04a91222091d7c8b 100644
--- a/chrome/browser/resources/print_preview/data/app_state.js
+++ b/chrome/browser/resources/print_preview/data/app_state.js
@@ -29,18 +29,25 @@ cr.define('print_preview', function() {
   };
 
   /**
+    * Number of recent print destinations to store across browser sessions.
+    * @const {number}
+    */
+  AppState.NUM_DESTINATIONS_ = 3;
+
+
+  /**
    * Enumeration of field names for serialized app state.
    * @enum {string}
    */
   AppState.Field = {
     VERSION: 'version',
-    SELECTED_DESTINATION_ID: 'selectedDestinationId',
-    SELECTED_DESTINATION_ACCOUNT: 'selectedDestinationAccount',
-    SELECTED_DESTINATION_ORIGIN: 'selectedDestinationOrigin',
-    SELECTED_DESTINATION_CAPABILITIES: 'selectedDestinationCapabilities',
-    SELECTED_DESTINATION_NAME: 'selectedDestinationName',
-    SELECTED_DESTINATION_EXTENSION_ID: 'selectedDestinationExtensionId',
-    SELECTED_DESTINATION_EXTENSION_NAME: 'selectedDestinationExtensionName',
+    RECENT_DESTINATION_IDS: 'recentDestinationIds',
+    RECENT_DESTINATION_ACCOUNTS: 'recentDestinationAccounts',
+    RECENT_DESTINATION_ORIGINS: 'recentDestinationOrigins',
+    RECENT_DESTINATION_CAPABILITIES: 'recentDestinationCapabilities',
+    RECENT_DESTINATION_NAMES: 'recentDestinationNames',
+    RECENT_DESTINATION_EXTENSION_IDS: 'recentDestinationExtensionIds',
+    RECENT_DESTINATION_EXTENSION_NAMES: 'recentDestinationExtensionNames',
     IS_GCP_PROMO_DISMISSED: 'isGcpPromoDismissed',
     DPI: 'dpi',
     MEDIA_SIZE: 'mediaSize',
@@ -74,14 +81,29 @@ cr.define('print_preview', function() {
   AppState.NATIVE_FUNCTION_NAME_ = 'saveAppState';
 
   AppState.prototype = {
+
+    /**
+      * Helper function to get the most recent value of one of the destination
+      * fields in the app state.
+      * @param {?print_preview.AppState.Field} fieldName The state field to
+      *     return the value of.
+      * @return {?string|?print_preview.Cdd} The most recent value of the
+      *     destination state field. ?print_preview.Cdd if the state field is
+      *     RECENT_DESTINATION_CAPABILIITIES, ?string otherwise.
+      */
+    getStateValue_: function(fieldName) {
+      return (this.state_[fieldName] && this.state_[fieldName].length > 0) ?
+          this.state_[fieldName][0] : null;
+    },
+
     /** @return {?string} ID of the selected destination. */
     get selectedDestinationId() {
-      return this.state_[AppState.Field.SELECTED_DESTINATION_ID];
+      return this.getStateValue_(AppState.Field.RECENT_DESTINATION_IDS);
     },
 
     /** @return {?string} Account the selected destination is registered for. */
     get selectedDestinationAccount() {
-      return this.state_[AppState.Field.SELECTED_DESTINATION_ACCOUNT];
+      return this.getStateValue_(AppState.Field.RECENT_DESTINATION_ACCOUNTS);
     },
 
     /**
@@ -89,24 +111,26 @@ cr.define('print_preview', function() {
      *     selected destination.
      */
     get selectedDestinationOrigin() {
-      return this.state_[AppState.Field.SELECTED_DESTINATION_ORIGIN];
+      return this.getStateValue_(AppState.Field.RECENT_DESTINATION_ORIGINS);
     },
 
     /** @return {?print_preview.Cdd} CDD of the selected destination. */
     get selectedDestinationCapabilities() {
-      return this.state_[AppState.Field.SELECTED_DESTINATION_CAPABILITIES];
+      return this.getStateValue_(
+          AppState.Field.RECENT_DESTINATION_CAPABILITIES);
     },
 
     /** @return {?string} Name of the selected destination. */
     get selectedDestinationName() {
-      return this.state_[AppState.Field.SELECTED_DESTINATION_NAME];
+      return this.getStateValue_(AppState.Field.RECENT_DESTINATION_NAMES);
     },
 
     /**
      * @return {?string} Extension ID associated with the selected destination.
      */
     get selectedDestinationExtensionId() {
-      return this.state_[AppState.Field.SELECTED_DESTINATION_EXTENSION_ID];
+      return this.getStateValue_(
+          AppState.Field.RECENT_DESTINATION_EXTENSION_IDS);
     },
 
     /**
@@ -114,7 +138,52 @@ cr.define('print_preview', function() {
      *     destination.
      */
     get selectedDestinationExtensionName() {
-      return this.state_[AppState.Field.SELECTED_DESTINATION_EXTENSION_NAME];
+      return this.getStateValue_(
+          AppState.Field.RECENT_DESTINATION_EXTENSION_NAMES);
+    },
+
+    /** @return {?Array<string>} IDs of the recent destinations. */
+    get recentDestinationIds() {
+      return this.state_[AppState.Field.RECENT_DESTINATION_IDS];
+    },
+
+    /**
+     * @return {?Array<string>} Accounts the recent destinations are registered
+     *     for.
+     */
+    get recentDestinationAccounts() {
+      return this.state_[AppState.Field.RECENT_DESTINATION_ACCOUNTS];
+    },
+
+    /** @return {?Array<string>} Origins of the recent destinations. */
+    get recentDestinationOrigins() {
+      return this.state_[AppState.Field.RECENT_DESTINATION_ORIGINS];
+    },
+
+    /** @return {?Array<print_preview.Cdd>} CDDs of the recent destinations. */
+    get recentDestinationCapabilities() {
+      return this.state_[AppState.Field.RECENT_DESTINATION_CAPABILITIES];
+    },
+
+    /** @return {?Array<string>} Names of the recent destinations. */
+    get recentDestinationNames() {
+      return this.state_[AppState.Field.RECENT_DESTINATION_NAMES];
+    },
+
+    /**
+     * @return {?Array<string>} Extension IDs associated with the recent
+     * destinations.
+     */
+    get recentDestinationExtensionIds() {
+      return this.state_[AppState.Field.RECENT_DESTINATION_EXTENSION_IDS];
+    },
+
+    /**
+     * @return {?Array<string>} Extension names associated with the recent
+     *     destinations.
+     */
+    get recentDestinationExtensionNames() {
+      return this.state_[AppState.Field.RECENT_DESTINATION_EXTENSION_NAMES];
     },
 
     /** @return {boolean} Whether the GCP promotion has been dismissed. */
@@ -145,6 +214,27 @@ cr.define('print_preview', function() {
     },
 
     /**
+     * Helper function to set up the recent destination fields in case they are
+     * empty or only contain one value.
+     * @param {print_preview.AppState.Field} stateFieldName The state field to
+     *     be set up.
+     */
+    setUpState_: function(stateFieldName) {
+      if (!this.state_[AppState.Field.RECENT_DESTINATION_IDS] ||
+          this.state_[AppState.Field.RECENT_DESTINATION_IDS].length == 0) {
+        // Ids must be a nonempty string or an Array instance. If it is null or
+        // an empty array, no destinations were saved.
+        this.state_[stateFieldName] = [];
+      } else if (!(this.state_[stateFieldName] instanceof Array)) {
+        var tmp = this.state_[stateFieldName];
+        this.state_[stateFieldName] = [tmp];
+      } else if (this.state_[stateFieldName].length >
+          AppState.NUM_DESTINATIONS_) {
+        this.state_[stateFieldName].length = AppState.NUM_DESTINATIONS_;
+      }
+    },
+
+    /**
      * Initializes the app state from a serialized string returned by the native
      * layer.
      * @param {?string} serializedAppStateStr Serialized string representation
@@ -164,7 +254,16 @@ cr.define('print_preview', function() {
       } else {
         // Set some state defaults.
         this.state_[AppState.Field.IS_GCP_PROMO_DISMISSED] = false;
+        this.state_[AppState.Field.RECENT_DESTINATION_IDS] = [];
       }
+
+      this.setUpState_(AppState.Field.RECENT_DESTINATION_IDS);
+      this.setUpState_(AppState.Field.RECENT_DESTINATION_ACCOUNTS);
+      this.setUpState_(AppState.Field.RECENT_DESTINATION_ORIGINS);
+      this.setUpState_(AppState.Field.RECENT_DESTINATION_CAPABILITIES);
+      this.setUpState_(AppState.Field.RECENT_DESTINATION_NAMES);
+      this.setUpState_(AppState.Field.RECENT_DESTINATION_EXTENSION_IDS);
+      this.setUpState_(AppState.Field.RECENT_DESTINATION_EXTENSION_NAMES);
     },
 
     /**
@@ -191,22 +290,68 @@ cr.define('print_preview', function() {
     },
 
     /**
+     * Shifts the desired recent destination field's values as needed and places
+     * the most recent value, destVal, in position 0 in the array.
+     * @param {number} indexFound The index where the destination already exists
+     *     in the array, or -1 if it is not in the array.
+     * @param {!print_preview.AppState.Field} fieldName The field array to
+     *     adjust
+     * @param {string or print_preview.Cdd} destVal The value that should be
+     *     added as the most recent value in the array.
+     */
+    shiftStateField_: function(indexFound, fieldName, destVal) {
+      if (indexFound == -1 &&
+          this.state_[fieldName].length == AppState.NUM_DESTINATIONS_)
+        indexFound = AppState.NUM_DESTINATIONS_ - 1;
+      if (indexFound != -1)
+        this.state_[fieldName].splice(indexFound, 1);
+      this.state_[fieldName].splice(0, 0, destVal);
+    },
+
+    /**
      * Persists the selected destination.
      * @param {!print_preview.Destination} dest Destination to persist.
      */
     persistSelectedDestination: function(dest) {
       if (!this.isInitialized_)
         return;
-      this.state_[AppState.Field.SELECTED_DESTINATION_ID] = dest.id;
-      this.state_[AppState.Field.SELECTED_DESTINATION_ACCOUNT] = dest.account;
-      this.state_[AppState.Field.SELECTED_DESTINATION_ORIGIN] = dest.origin;
-      this.state_[AppState.Field.SELECTED_DESTINATION_CAPABILITIES] =
-          dest.capabilities;
-      this.state_[AppState.Field.SELECTED_DESTINATION_NAME] = dest.displayName;
-      this.state_[AppState.Field.SELECTED_DESTINATION_EXTENSION_ID] =
-          dest.extensionId;
-      this.state_[AppState.Field.SELECTED_DESTINATION_EXTENSION_NAME] =
-          dest.extensionName;
+
+      // Determine if this destination is already in the recent destinations,
+      // and where in the array it is located.
+      var idIndexFound = this.state_[
+          AppState.Field.RECENT_DESTINATION_IDS].indexOf(dest.id);
+      var originIndexFound = this.state_[
+          AppState.Field.RECENT_DESTINATION_ORIGINS].indexOf(dest.origin);
+
+      if (idIndexFound != originIndexFound ||
+          idIndexFound >= AppState.NUM_DESTINATIONS_)
+        idIndexFound = -1;
+
+      if (idIndexFound == 0) {
+        this.persist_();
+        return;
+      }
+
+      // Shift all the destination state fields so that the are always ordered
+      // from most recent (entry 0) to least recent.
+      this.shiftStateField_(idIndexFound,
+          AppState.Field.RECENT_DESTINATION_IDS, dest.id);
+      this.shiftStateField_(idIndexFound,
+          AppState.Field.RECENT_DESTINATION_ACCOUNTS, dest.account || '');
+      this.shiftStateField_(idIndexFound,
+          AppState.Field.RECENT_DESTINATION_ORIGINS, dest.origin);
+      this.shiftStateField_(idIndexFound,
+          AppState.Field.RECENT_DESTINATION_CAPABILITIES,
+          dest.capabilities);
+      this.shiftStateField_(idIndexFound,
+          AppState.Field.RECENT_DESTINATION_NAMES, dest.name || '');
+      this.shiftStateField_(idIndexFound,
+          AppState.Field.RECENT_DESTINATION_EXTENSION_IDS,
+          dest.extension_id || '');
+      this.shiftStateField_(idIndexFound,
+          AppState.Field.RECENT_DESTINATION_EXTENSION_NAMES,
+          dest.extension_name || '');
+
       this.persist_();
     },