Adds local database for the editor parcelable saved instance data

Author: antonis

libs/editor/src/main/java/org/wordpress/android/editor/SavedInstanceDatabase.kt

@@ -0,0 +1,80 @@
+package org.wordpress.android.editor
+
+import android.content.Context
+import android.database.sqlite.SQLiteDatabase
+import android.database.sqlite.SQLiteOpenHelper
+import android.os.Parcelable
+import org.wordpress.android.editor.SavedParcelTable.createTable
+import org.wordpress.android.editor.SavedParcelTable.dropTable
+
+/**
+ * Database for the saved instance state data
+ */
+class SavedInstanceDatabase(context: Context?) : SQLiteOpenHelper(context, DB_NAME, null, DB_VERSION) {
+    override fun onOpen(db: SQLiteDatabase) {
+        super.onOpen(db)
+    }
+
+    override fun onCreate(db: SQLiteDatabase) {
+        createAllTables(db)
+    }
+
+    override fun onUpgrade(db: SQLiteDatabase, oldVersion: Int, newVersion: Int) {
+        reset(db)
+    }
+
+    override fun onDowngrade(db: SQLiteDatabase, oldVersion: Int, newVersion: Int) {
+        reset(db)
+    }
+
+    private fun createAllTables(db: SQLiteDatabase) {
+        createTable(db)
+    }
+
+    private fun dropAllTables(db: SQLiteDatabase) {
+        dropTable(db)
+    }
+
+    private fun reset(db: SQLiteDatabase) {
+        db.beginTransaction()
+        try {
+            dropAllTables(db)
+            createAllTables(db)
+            db.setTransactionSuccessful()
+        } finally {
+            db.endTransaction()
+        }
+    }
+
+    fun addParcel(parcelId: String, parcel: Parcelable?) {
+        parcel?.let {
+            SavedParcelTable.addParcel(writableDatabase, parcelId, it)
+        }
+    }
+
+    fun <T> getParcel(parcelId: String, creator: Parcelable.Creator<T>): T? {
+        return SavedParcelTable.getParcel(readableDatabase, parcelId, creator)
+    }
+
+    companion object {
+        private const val DB_NAME = "wpsavedinstance.db"
+        private const val DB_VERSION = 1
+
+        private var mSavedInstanceDb: SavedInstanceDatabase? = null
+        private val DB_LOCK = Any()
+
+        fun getDatabase(context: Context): SavedInstanceDatabase? {
+            if (mSavedInstanceDb == null) {
+                synchronized(DB_LOCK) {
+                    if (mSavedInstanceDb == null) {
+                        mSavedInstanceDb = SavedInstanceDatabase(context.applicationContext)
+                        // this ensures that onOpen() is called with a writable database
+                        // (open will fail if app calls getReadableDb() first)
+                        mSavedInstanceDb?.writableDatabase
+                    }
+                }
+            }
+            return mSavedInstanceDb
+        }
+    }
+}

libs/editor/src/main/java/org/wordpress/android/editor/SavedParcelTable.kt

@@ -0,0 +1,83 @@
+package org.wordpress.android.editor
+
+import android.content.ContentValues
+import android.database.sqlite.SQLiteDatabase
+import android.os.Parcel
+import android.os.Parcelable
+import org.wordpress.android.util.SqlUtils
+
+object SavedParcelTable {
+    private const val SAVED_PARCEL_TABLE = "tbl_saved_parcel"
+    private const val PARCEL_ID = "parcel_id"
+    private const val PARCEL_DATA = "parcel_data"
+    fun createTable(db: SQLiteDatabase) {
+        db.execSQL(
+            "CREATE TABLE " + SAVED_PARCEL_TABLE + " ("
+                    + PARCEL_ID + " TEXT,"
+                    + PARCEL_DATA + " BLOB,"
+                    + " PRIMARY KEY (" + PARCEL_ID + ")"
+                    + ")"
+        )
+    }
+
+    fun dropTable(db: SQLiteDatabase) {
+        db.execSQL("DROP TABLE IF EXISTS $SAVED_PARCEL_TABLE")
+    }
+
+    fun reset(db: SQLiteDatabase) {
+        dropTable(db)
+        createTable(db)
+    }
+
+    fun addParcel(writableDb: SQLiteDatabase?, parcelId: String, parcel: Parcelable) {
+        val parcelable = ParcelableObject(parcel)
+        val values = ContentValues()
+        values.put(PARCEL_ID, parcelId)
+        values.put(PARCEL_DATA, parcelable.toBytes())
+        writableDb?.insertWithOnConflict(SAVED_PARCEL_TABLE, null, values, SQLiteDatabase.CONFLICT_REPLACE)
+        parcelable.recycle()
+    }
+
+    fun <T> getParcel(readableDb: SQLiteDatabase?, parcelId: String, creator: Parcelable.Creator<T>): T? {
+        val db = readableDb ?: return null
+        val c = db.rawQuery("SELECT * FROM $SAVED_PARCEL_TABLE WHERE $PARCEL_ID ='$parcelId'", null)
+        return try {
+            if (c.moveToFirst()) {
+                val parcelableObject = ParcelableObject(c.getBlob(c.getColumnIndexOrThrow(PARCEL_DATA)))
+                val parcelable = creator.createFromParcel(parcelableObject.getParcel())
+                parcelableObject.recycle()
+                parcelable
+            } else {
+                null
+            }
+        } finally {
+            SqlUtils.closeCursor(c)
+        }
+    }
+
+    private class ParcelableObject {
+        private val parcel = Parcel.obtain()
+
+        constructor(parcelable: Parcelable) {
+            parcelable.writeToParcel(parcel, 0)
+        }
+
+        constructor(data: ByteArray) {
+            parcel.unmarshall(data, 0, data.size)
+            parcel.setDataPosition(0)
+        }
+
+        fun toBytes(): ByteArray {
+            return parcel.marshall()
+        }
+
+        fun getParcel(): Parcel {
+            parcel.setDataPosition(0)
+            return parcel
+        }
+
+        fun recycle() {
+            parcel.recycle()
+        }
+    }
+}