[sql] Allow storing mmap status in a VIEW instead of meta table.

sql/connection_unittest.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include "base/bind.h"
 #include "base/files/file_util.h"
 #include "base/files/scoped_file.h"
@@ skipping 297 matching lines @@
   EXPECT_FALSE(db().HasCachedStatement(SQL_FROM_HERE));
 }
 
 TEST_F(SQLConnectionTest, IsSQLValidTest) {
   ASSERT_TRUE(db().Execute("CREATE TABLE foo (a, b)"));
   ASSERT_TRUE(db().IsSQLValid("SELECT a FROM foo"));
   ASSERT_FALSE(db().IsSQLValid("SELECT no_exist FROM foo"));
 }
 
 TEST_F(SQLConnectionTest, DoesStuffExist) {
-  // Test DoesTableExist.
+  // Test DoesTableExist and DoesIndexExist.
   EXPECT_FALSE(db().DoesTableExist("foo"));
   ASSERT_TRUE(db().Execute("CREATE TABLE foo (a, b)"));
   ASSERT_TRUE(db().Execute("CREATE INDEX foo_a ON foo (a)"));
+  EXPECT_FALSE(db().DoesIndexExist("foo"));
   EXPECT_TRUE(db().DoesTableExist("foo"));
   EXPECT_TRUE(db().DoesIndexExist("foo_a"));
+  EXPECT_FALSE(db().DoesTableExist("foo_a"));
+
+  // Test DoesViewExist.  The CREATE VIEW is an older form because some iOS
+  // versions use an earlier version of SQLite, and the difference isn't
+  // relevant for this test.
+  EXPECT_FALSE(db().DoesViewExist("voo"));
+  ASSERT_TRUE(db().Execute("CREATE VIEW voo AS SELECT 1"));
+  EXPECT_FALSE(db().DoesIndexExist("voo"));
+  EXPECT_FALSE(db().DoesTableExist("voo"));
+  EXPECT_TRUE(db().DoesViewExist("voo"));
 
   // Test DoesColumnExist.
   EXPECT_FALSE(db().DoesColumnExist("foo", "bar"));
   EXPECT_TRUE(db().DoesColumnExist("foo", "a"));
 
   // Testing for a column on a nonexistent table.
   EXPECT_FALSE(db().DoesColumnExist("bar", "b"));
 
   // Names are not case sensitive.
   EXPECT_TRUE(db().DoesTableExist("FOO"));
@@ skipping 1130 matching lines @@
       ASSERT_TRUE(s.Step());
       EXPECT_LE(s.ColumnInt(0), 0);
     }
   }
 
   // Test that explicit disable prevents mmap'ed I/O.
   db().Close();
   sql::Connection::Delete(db_path());
   db().set_mmap_disabled();
   ASSERT_TRUE(db().Open(db_path()));
+  EXPECT_EQ("0", ExecuteWithResult(&db(), "PRAGMA mmap_size"));
+}
+
+// Test whether a fresh database gets mmap enabled when using alternate status
+// storage.
+TEST_F(SQLConnectionTest, MmapInitiallyEnabledAltStatus) {
+  // Re-open fresh database with alt-status flag set.
+  db().Close();
+  sql::Connection::Delete(db_path());
+  db().set_mmap_alt_status();
+  ASSERT_TRUE(db().Open(db_path()));
+
   {
     sql::Statement s(db().GetUniqueStatement("PRAGMA mmap_size"));
-    ASSERT_TRUE(s.Step());
-    EXPECT_LE(s.ColumnInt(0), 0);
+
+    // SQLite doesn't have mmap support (perhaps an early iOS release).
+    if (!s.Step())
+      return;
+
+    // If mmap I/O is not on, attempt to turn it on.  If that succeeds, then
+    // Open() should have turned it on.  If mmap support is disabled, 0 is
+    // returned.  If the VFS does not understand SQLITE_FCNTL_MMAP_SIZE (for
+    // instance MojoVFS), -1 is returned.
+    if (s.ColumnInt(0) <= 0) {
+      ASSERT_TRUE(db().Execute("PRAGMA mmap_size = 1048576"));
+      s.Reset(true);
+      ASSERT_TRUE(s.Step());
+      EXPECT_LE(s.ColumnInt(0), 0);
+    }
   }
+
+  // Test that explicit disable overrides set_mmap_alt_status().
+  db().Close();
+  sql::Connection::Delete(db_path());
+  db().set_mmap_disabled();
+  ASSERT_TRUE(db().Open(db_path()));
+  EXPECT_EQ("0", ExecuteWithResult(&db(), "PRAGMA mmap_size"));
 }
 
 TEST_F(SQLConnectionTest, GetAppropriateMmapSize) {
 #if defined(OS_IOS) && defined(USE_SYSTEM_SQLITE)
   // Mmap is not supported on iOS9.
   if (!base::ios::IsRunningOnIOS10OrLater()) {
     ASSERT_EQ(0UL, db().GetAppropriateMmapSize());
     return;
   }
 #endif
@@ skipping 27 matching lines @@
   ASSERT_EQ(0, mmap_status);
 
   // With no key, map everything and create the key.
   // TODO(shess): This really should be "maps everything after validating it",
   // but that is more complicated to structure.
   ASSERT_GT(db().GetAppropriateMmapSize(), kMmapAlot);
   ASSERT_TRUE(MetaTable::GetMmapStatus(&db(), &mmap_status));
   ASSERT_EQ(MetaTable::kMmapSuccess, mmap_status);
 }
 
+TEST_F(SQLConnectionTest, GetAppropriateMmapSizeAltStatus) {
+#if defined(OS_IOS) && defined(USE_SYSTEM_SQLITE)
+  // Mmap is not supported on iOS9.  Make sure that test takes precedence.
+  if (!base::ios::IsRunningOnIOS10OrLater()) {
+    db().set_mmap_alt_status();
+    ASSERT_EQ(0UL, db().GetAppropriateMmapSize());
+    return;
+  }
+#endif
+
+  const size_t kMmapAlot = 25 * 1024 * 1024;
+
+  // At this point, Connection still expects a future [meta] table.
+  ASSERT_FALSE(db().DoesTableExist("meta"));
+  ASSERT_FALSE(db().DoesViewExist("MmapStatus"));
+  ASSERT_GT(db().GetAppropriateMmapSize(), kMmapAlot);
+  ASSERT_FALSE(db().DoesTableExist("meta"));
+  ASSERT_FALSE(db().DoesViewExist("MmapStatus"));
+
+  // Using alt status, everything should be mapped, with state in the view.
+  db().set_mmap_alt_status();
+  ASSERT_GT(db().GetAppropriateMmapSize(), kMmapAlot);
+  ASSERT_FALSE(db().DoesTableExist("meta"));
+  ASSERT_TRUE(db().DoesViewExist("MmapStatus"));
+  EXPECT_EQ(base::IntToString(MetaTable::kMmapSuccess),
+            ExecuteWithResult(&db(), "SELECT * FROM MmapStatus"));
+
+  // Also maps everything when kMmapSuccess is in the view.
+  ASSERT_GT(db().GetAppropriateMmapSize(), kMmapAlot);
+
+  // Failure status leads to nothing being mapped.
+  ASSERT_TRUE(db().Execute("DROP VIEW MmapStatus"));
+  ASSERT_TRUE(db().Execute("CREATE VIEW MmapStatus AS SELECT -2"));
+  ASSERT_EQ(0UL, db().GetAppropriateMmapSize());
+  EXPECT_EQ(base::IntToString(MetaTable::kMmapFailure),
+            ExecuteWithResult(&db(), "SELECT * FROM MmapStatus"));
+}
+
 // To prevent invalid SQL from accidentally shipping to production, prepared
 // statements which fail to compile with SQLITE_ERROR call DLOG(FATAL).  This
 // case cannot be suppressed with an error callback.
 TEST_F(SQLConnectionTest, CompileError) {
   // DEATH tests not supported on Android or iOS.
 #if !defined(OS_ANDROID) && !defined(OS_IOS)
   if (DLOG_IS_ON(FATAL)) {
     db().set_error_callback(base::Bind(&IgnoreErrorCallback));
     ASSERT_DEATH({
         db().GetUniqueStatement("SELECT x");
       }, "SQL compile error no such column: x");
   }
 #endif
 }
 
 }  // namespace sql