From 79303570de1b7960bf70bf1d2be1c213e1e26991 Mon Sep 17 00:00:00 2001
From: Lucas Rocha <lucasr@mozilla.com>
Date: Tue, 4 Mar 2014 16:52:13 +0000
Subject: [PATCH] Bug 975841 - Bootstrap schema upgrade path in HomeProvide.jsm

---
 mobile/android/base/db/HomeProvider.java |  2 +-
 mobile/android/modules/HomeProvider.jsm  | 51 +++++++++++++++++++-----
 2 files changed, 43 insertions(+), 10 deletions(-)

diff --git a/mobile/android/base/db/HomeProvider.java b/mobile/android/base/db/HomeProvider.java
index e8de64de472..788fb0145a3 100644
--- a/mobile/android/base/db/HomeProvider.java
+++ b/mobile/android/base/db/HomeProvider.java
@@ -25,7 +25,7 @@ public class HomeProvider extends SQLiteBridgeContentProvider {
     private static final String LOGTAG = "GeckoHomeProvider";
 
     // This should be kept in sync with the db version in mobile/android/modules/HomeProvider.jsm
-    private static int DB_VERSION = 1;
+    private static int DB_VERSION = 2;
     private static String DB_FILENAME = "home.sqlite";
 
     private static final String TABLE_ITEMS = "items";
diff --git a/mobile/android/modules/HomeProvider.jsm b/mobile/android/modules/HomeProvider.jsm
index 0befd254856..e42f11e0330 100644
--- a/mobile/android/modules/HomeProvider.jsm
+++ b/mobile/android/modules/HomeProvider.jsm
@@ -17,12 +17,11 @@ Cu.import("resource://gre/modules/Task.jsm");
 Cu.import("resource://gre/modules/XPCOMUtils.jsm");
 
 /*
- * XXX: Add migration logic to getDatabaseConnection if you ever rev SCHEMA_VERSION.
- *
  * SCHEMA_VERSION history:
  *   1: Create HomeProvider (bug 942288)
+ *   2: Add filter column to items table (bug 942295/975841)
  */
-const SCHEMA_VERSION = 1;
+const SCHEMA_VERSION = 2;
 
 XPCOMUtils.defineLazyGetter(this, "DB_PATH", function() {
   return OS.Path.join(OS.Constants.Path.profileDir, "home.sqlite");
@@ -55,6 +54,9 @@ const SQL = {
       "created INTEGER" +
     ")",
 
+  dropItemsTable:
+    "DROP TABLE items",
+
   insertItem:
     "INSERT INTO items (dataset_id, url, title, description, image_url, filter, created) " +
       "VALUES (:dataset_id, :url, :title, :description, :image_url, :filter, :created)",
@@ -181,6 +183,33 @@ this.HomeProvider = Object.freeze({
 
 var gDatabaseEnsured = false;
 
+/**
+ * Creates the database schema.
+ */
+function createDatabase(db) {
+  return Task.spawn(function create_database_task() {
+    yield db.execute(SQL.createItemsTable);
+  });
+}
+
+/**
+ * Migrates the database schema to a new version.
+ */
+function upgradeDatabase(db, oldVersion, newVersion) {
+  return Task.spawn(function upgrade_database_task() {
+    for (let v = oldVersion + 1; v <= newVersion; v++) {
+      switch(v) {
+        case 2:
+          // Recreate the items table discarding any
+          // existing data.
+          yield db.execute(SQL.dropItemsTable);
+          yield db.execute(SQL.createItemsTable);
+          break;
+      }
+    }
+  });
+}
+
 /**
  * Opens a database connection and makes sure that the database schema version
  * is correct, performing migrations if necessary. Consumers should be sure
@@ -198,13 +227,17 @@ function getDatabaseConnection() {
 
     try {
       // Check to see if we need to perform any migrations.
-      // XXX: We will need to add migration logic if we ever rev SCHEMA_VERSION.
-      let dbVersion = yield db.getSchemaVersion();
-      if (parseInt(dbVersion) < SCHEMA_VERSION) {
-        // For schema v1, create the items table and set the schema version.
-        yield db.execute(SQL.createItemsTable);
-        yield db.setSchemaVersion(SCHEMA_VERSION);
+      let dbVersion = parseInt(yield db.getSchemaVersion());
+
+      // getSchemaVersion() returns a 0 int if the schema
+      // version is undefined.
+      if (dbVersion === 0) {
+        yield createDatabase(db);
+      } else if (dbVersion < SCHEMA_VERSION) {
+        yield upgradeDatabase(db, dbVersion, SCHEMA_VERSION);
       }
+
+      yield db.setSchemaVersion(SCHEMA_VERSION);
     } catch(e) {
       // Close the DB connection before passing the exception to the consumer.
       yield db.close();