Bug 1135086 - Implement in-place computed UPDATE in DBUtils. r=margaret

Sometimes it's convenient to want to do an UPDATE query like:

  UPDATE foo
  SET bar = bar | 5

or similar -- that is, refer to existing values in the SET expression.

This patch allows that, accepting an array of ContentValues and an array of
operations as input. A single UPDATE will be constructed from the entire input.

mobile/android/base/db/DBUtils.java

@@ -4,7 +4,11 @@
 
 package org.mozilla.gecko.db;
 
+import android.annotation.TargetApi;
 import android.database.sqlite.SQLiteDatabase;
+import android.database.sqlite.SQLiteStatement;
+import android.os.Build;
+import org.mozilla.gecko.AppConstants;
 import org.mozilla.gecko.GeckoAppShell;
 import org.mozilla.gecko.GeckoProfile;
 
@@ -15,6 +19,9 @@ import android.net.Uri;
 import android.text.TextUtils;
 import android.util.Log;
 import org.mozilla.gecko.Telemetry;
+import org.mozilla.gecko.mozglue.RobocopTarget;
+
+import java.util.Map;
 
 public class DBUtils {
     private static final String LOGTAG = "GeckoDBUtils";
@@ -173,4 +180,175 @@ public class DBUtils {
         }
         return appendProfile(profile, uri);
     }
+
+    /**
+     * Use the following when no conflict action is specified.
+     */
+    private static final int CONFLICT_NONE = 0;
+    private static final String[] CONFLICT_VALUES = new String[] {"", " OR ROLLBACK ", " OR ABORT ", " OR FAIL ", " OR IGNORE ", " OR REPLACE "};
+
+    /**
+     * Convenience method for updating rows in the database.
+     *
+     * @param table the table to update in
+     * @param values a map from column names to new column values. null is a
+     *            valid value that will be translated to NULL.
+     * @param whereClause the optional WHERE clause to apply when updating.
+     *            Passing null will update all rows.
+     * @param whereArgs You may include ?s in the where clause, which
+     *            will be replaced by the values from whereArgs. The values
+     *            will be bound as Strings.
+     * @return the number of rows affected
+     */
+    @RobocopTarget
+    public static int updateArrays(SQLiteDatabase db, String table, ContentValues[] values, UpdateOperation[] ops, String whereClause, String[] whereArgs) {
+        return updateArraysWithOnConflict(db, table, values, ops, whereClause, whereArgs, CONFLICT_NONE, true);
+    }
+
+    public static void updateArraysBlindly(SQLiteDatabase db, String table, ContentValues[] values, UpdateOperation[] ops, String whereClause, String[] whereArgs) {
+        updateArraysWithOnConflict(db, table, values, ops, whereClause, whereArgs, CONFLICT_NONE, false);
+    }
+
+    @RobocopTarget
+    public enum UpdateOperation {
+        ASSIGN,
+        BITWISE_OR,
+    }
+
+    /**
+     * This is an evil reimplementation of SQLiteDatabase's methods to allow for
+     * smarter updating.
+     *
+     * Each ContentValues has an associated enum that describes how to unify input values with the existing column values.
+     */
+    private static int updateArraysWithOnConflict(SQLiteDatabase db, String table,
+                                          ContentValues[] values,
+                                          UpdateOperation[] ops,
+                                          String whereClause,
+                                          String[] whereArgs,
+                                          int conflictAlgorithm,
+                                          boolean returnChangedRows) {
+        if (values == null || values.length == 0) {
+            throw new IllegalArgumentException("Empty values");
+        }
+
+        if (ops == null || ops.length != values.length) {
+            throw new IllegalArgumentException("ops and values don't match");
+        }
+
+        StringBuilder sql = new StringBuilder(120);
+        sql.append("UPDATE ");
+        sql.append(CONFLICT_VALUES[conflictAlgorithm]);
+        sql.append(table);
+        sql.append(" SET ");
+
+        // move all bind args to one array
+        int setValuesSize = 0;
+        for (int i = 0; i < values.length; i++) {
+            setValuesSize += values[i].size();
+        }
+
+        int bindArgsSize = (whereArgs == null) ? setValuesSize : (setValuesSize + whereArgs.length);
+        Object[] bindArgs = new Object[bindArgsSize];
+
+        int arg = 0;
+        for (int i = 0; i < values.length; i++) {
+            final ContentValues v = values[i];
+            final UpdateOperation op = ops[i];
+
+            // Alas, code duplication.
+            switch (op) {
+                case ASSIGN:
+                    for (Map.Entry<String, Object> entry : v.valueSet()) {
+                        final String colName = entry.getKey();
+                        sql.append((arg > 0) ? "," : "");
+                        sql.append(colName);
+                        bindArgs[arg++] = entry.getValue();
+                        sql.append("= ?");
+                    }
+                    break;
+                case BITWISE_OR:
+                    for (Map.Entry<String, Object> entry : v.valueSet()) {
+                        final String colName = entry.getKey();
+                        sql.append((arg > 0) ? "," : "");
+                        sql.append(colName);
+                        bindArgs[arg++] = entry.getValue();
+                        sql.append("= ? | ");
+                        sql.append(colName);
+                    }
+                    break;
+            }
+        }
+
+        if (whereArgs != null) {
+            for (arg = setValuesSize; arg < bindArgsSize; arg++) {
+                bindArgs[arg] = whereArgs[arg - setValuesSize];
+            }
+        }
+        if (!TextUtils.isEmpty(whereClause)) {
+            sql.append(" WHERE ");
+            sql.append(whereClause);
+        }
+
+        // What a huge pain in the ass, all because SQLiteDatabase doesn't expose .executeSql,
+        // and we can't get a DB handle. Nor can we easily construct a statement with arguments
+        // already bound.
+        final SQLiteStatement statement = db.compileStatement(sql.toString());
+        try {
+            bindAllArgs(statement, bindArgs);
+            if (!returnChangedRows) {
+                statement.execute();
+                return 0;
+            }
+
+            if (AppConstants.Versions.feature11Plus) {
+                // This is a separate method so we can annotate it with @TargetApi.
+                return executeStatementReturningChangedRows(statement);
+            } else {
+                statement.execute();
+                final Cursor cursor = db.rawQuery("SELECT changes()", null);
+                try {
+                    cursor.moveToFirst();
+                    return cursor.getInt(0);
+                } finally {
+                    cursor.close();
+                }
+
+            }
+        } finally {
+            statement.close();
+        }
+    }
+
+    @TargetApi(Build.VERSION_CODES.HONEYCOMB)
+    private static int executeStatementReturningChangedRows(SQLiteStatement statement) {
+        return statement.executeUpdateDelete();
+    }
+
+    // All because {@link SQLiteProgram#bind(integer, Object)} is private.
+    private static void bindAllArgs(SQLiteStatement statement, Object[] bindArgs) {
+        if (bindArgs == null) {
+            return;
+        }
+        for (int i = bindArgs.length; i != 0; i--) {
+            Object v = bindArgs[i - 1];
+            if (v == null) {
+                statement.bindNull(i);
+            } else if (v instanceof String) {
+                statement.bindString(i, (String) v);
+            } else if (v instanceof Double) {
+                statement.bindDouble(i, (Double) v);
+            } else if (v instanceof Float) {
+                statement.bindDouble(i, (Float) v);
+            } else if (v instanceof Long) {
+                statement.bindLong(i, (Long) v);
+            } else if (v instanceof Integer) {
+                statement.bindLong(i, (Integer) v);
+            } else if (v instanceof Byte) {
+                statement.bindLong(i, (Byte) v);
+            } else if (v instanceof byte[]) {
+                statement.bindBlob(i, (byte[]) v);
+            }
+        }
+    }
 }

mobile/android/base/tests/robocop.ini

@@ -33,6 +33,7 @@ skip-if = android_version == "10"
 [testClearPrivateData]
 # disabled on x86 and 2.3; bug 948591
 skip-if = android_version == "10" || processor == "x86"
+[testDBUtils]
 [testDistribution]
 [testDoorHanger]
 [testFilterOpenTab]

mobile/android/base/tests/testDBUtils.java

@@ -0,0 +1,70 @@
+/* -*- Mode: Java; c-basic-offset: 4; tab-width: 20; indent-tabs-mode: nil; -*-
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.tests;
+
+import android.content.ContentValues;
+import android.database.Cursor;
+import android.database.sqlite.SQLiteDatabase;
+import org.mozilla.gecko.db.DBUtils;
+
+import java.io.File;
+import java.io.IOException;
+
+public class testDBUtils extends BaseTest {
+    public void testDBUtils() throws IOException {
+        final File cacheDir = getInstrumentation().getContext().getCacheDir();
+        final File dbFile = File.createTempFile("testDBUtils", ".db", cacheDir);
+        final SQLiteDatabase db = SQLiteDatabase.openOrCreateDatabase(dbFile, null);
+        try {
+            mAsserter.ok(db != null, "Created DB.", null);
+            db.execSQL("CREATE TABLE foo (x INTEGER NOT NULL DEFAULT 0, y TEXT)");
+            final ContentValues v = new ContentValues();
+            v.put("x", 5);
+            v.put("y", "a");
+            db.insert("foo", null, v);
+            v.put("x", 2);
+            v.putNull("y");
+            db.insert("foo", null, v);
+            v.put("x", 3);
+            v.put("y", "z");
+            db.insert("foo", null, v);
+
+            DBUtils.UpdateOperation[] ops = {DBUtils.UpdateOperation.BITWISE_OR, DBUtils.UpdateOperation.ASSIGN};
+            ContentValues[] values = {new ContentValues(), new ContentValues()};
+            values[0].put("x", 0xff);
+            values[1].put("y", "hello");
+
+            final int updated = DBUtils.updateArrays(db, "foo", values, ops, "x >= 3", null);
+
+            mAsserter.ok(updated == 2, "Updated two rows.", null);
+            final Cursor out = db.query("foo", new String[]{"x", "y"}, null, null, null, null, "x");
+            try {
+                mAsserter.ok(out.moveToNext(), "Has first result.", null);
+                mAsserter.ok(2 == out.getInt(0), "1: First column was untouched.", null);
+                mAsserter.ok(out.isNull(1), "1: Second column was untouched.", null);
+
+                mAsserter.ok(out.moveToNext(), "Has second result.", null);
+                mAsserter.ok((0xff | 3) == out.getInt(0), "2: First column was ORed correctly.", null);
+                mAsserter.ok("hello".equals(out.getString(1)), "2: Second column was assigned correctly.", null);
+
+                mAsserter.ok(out.moveToNext(), "Has third result.", null);
+                mAsserter.ok((0xff | 5) == out.getInt(0), "3: First column was ORed correctly.", null);
+                mAsserter.ok("hello".equals(out.getString(1)), "3: Second column was assigned correctly.", null);
+
+                mAsserter.ok(!out.moveToNext(), "No more results.", null);
+            } finally {
+                out.close();
+            }
+
+        } finally {
+            try {
+                db.close();
+            } catch (Exception e) {
+            }
+            dbFile.delete();
+        }
+    }
+}