1 files changed, 420 insertions, 0 deletions
diff --git a/sql/connection.cc b/sql/connection.cc
new file mode 100644
index 0000000..3f63301
--- /dev/null
+++ b/sql/connection.cc
@@ -0,0 +1,420 @@
+// Copyright (c) 2011 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 "sql/connection.h"
+
+#include <string.h>
+
+#include "base/file_path.h"
+#include "base/logging.h"
+#include "base/string_util.h"
+#include "base/stringprintf.h"
+#include "base/utf_string_conversions.h"
+#include "sql/statement.h"
+#include "third_party/sqlite/sqlite3.h"
+
+namespace {
+
+// Spin for up to a second waiting for the lock to clear when setting
+// up the database.
+// TODO(shess): Better story on this.  http://crbug.com/56559
+const base::TimeDelta kBusyTimeout = base::TimeDelta::FromSeconds(1);
+
+class ScopedBusyTimeout {
+ public:
+  explicit ScopedBusyTimeout(sqlite3* db)
+      : db_(db) {
+  }
+  ~ScopedBusyTimeout() {
+    sqlite3_busy_timeout(db_, 0);
+  }
+
+  int SetTimeout(base::TimeDelta timeout) {
+    DCHECK_LT(timeout.InMilliseconds(), INT_MAX);
+    return sqlite3_busy_timeout(db_,
+                                static_cast<int>(timeout.InMilliseconds()));
+  }
+
+ private:
+  sqlite3* db_;
+};
+
+}  // namespace
+
+namespace sql {
+
+bool StatementID::operator<(const StatementID& other) const {
+  if (number_ != other.number_)
+    return number_ < other.number_;
+  return strcmp(str_, other.str_) < 0;
+}
+
+ErrorDelegate::ErrorDelegate() {
+}
+
+ErrorDelegate::~ErrorDelegate() {
+}
+
+Connection::StatementRef::StatementRef()
+    : connection_(NULL),
+      stmt_(NULL) {
+}
+
+Connection::StatementRef::StatementRef(Connection* connection,
+                                       sqlite3_stmt* stmt)
+    : connection_(connection),
+      stmt_(stmt) {
+  connection_->StatementRefCreated(this);
+}
+
+Connection::StatementRef::~StatementRef() {
+  if (connection_)
+    connection_->StatementRefDeleted(this);
+  Close();
+}
+
+void Connection::StatementRef::Close() {
+  if (stmt_) {
+    sqlite3_finalize(stmt_);
+    stmt_ = NULL;
+  }
+  connection_ = NULL;  // The connection may be getting deleted.
+}
+
+Connection::Connection()
+    : db_(NULL),
+      page_size_(0),
+      cache_size_(0),
+      exclusive_locking_(false),
+      transaction_nesting_(0),
+      needs_rollback_(false) {
+}
+
+Connection::~Connection() {
+  Close();
+}
+
+bool Connection::Open(const FilePath& path) {
+#if defined(OS_WIN)
+  return OpenInternal(WideToUTF8(path.value()));
+#elif defined(OS_POSIX)
+  return OpenInternal(path.value());
+#endif
+}
+
+bool Connection::OpenInMemory() {
+  return OpenInternal(":memory:");
+}
+
+void Connection::Close() {
+  statement_cache_.clear();
+  DCHECK(open_statements_.empty());
+  if (db_) {
+    sqlite3_close(db_);
+    db_ = NULL;
+  }
+}
+
+void Connection::Preload() {
+  if (!db_) {
+    NOTREACHED();
+    return;
+  }
+
+  // A statement must be open for the preload command to work. If the meta
+  // table doesn't exist, it probably means this is a new database and there
+  // is nothing to preload (so it's OK we do nothing).
+  if (!DoesTableExist("meta"))
+    return;
+  Statement dummy(GetUniqueStatement("SELECT * FROM meta"));
+  if (!dummy || !dummy.Step())
+    return;
+
+#if !defined(USE_SYSTEM_SQLITE)
+  // This function is only defined in Chromium's version of sqlite.
+  // Do not call it when using system sqlite.
+  sqlite3_preload(db_);
+#endif
+}
+
+bool Connection::BeginTransaction() {
+  if (needs_rollback_) {
+    DCHECK_GT(transaction_nesting_, 0);
+
+    // When we're going to rollback, fail on this begin and don't actually
+    // mark us as entering the nested transaction.
+    return false;
+  }
+
+  bool success = true;
+  if (!transaction_nesting_) {
+    needs_rollback_ = false;
+
+    Statement begin(GetCachedStatement(SQL_FROM_HERE, "BEGIN TRANSACTION"));
+    if (!begin || !begin.Run())
+      return false;
+  }
+  transaction_nesting_++;
+  return success;
+}
+
+void Connection::RollbackTransaction() {
+  if (!transaction_nesting_) {
+    NOTREACHED() << "Rolling back a nonexistent transaction";
+    return;
+  }
+
+  transaction_nesting_--;
+
+  if (transaction_nesting_ > 0) {
+    // Mark the outermost transaction as needing rollback.
+    needs_rollback_ = true;
+    return;
+  }
+
+  DoRollback();
+}
+
+bool Connection::CommitTransaction() {
+  if (!transaction_nesting_) {
+    NOTREACHED() << "Rolling back a nonexistent transaction";
+    return false;
+  }
+  transaction_nesting_--;
+
+  if (transaction_nesting_ > 0) {
+    // Mark any nested transactions as failing after we've already got one.
+    return !needs_rollback_;
+  }
+
+  if (needs_rollback_) {
+    DoRollback();
+    return false;
+  }
+
+  Statement commit(GetCachedStatement(SQL_FROM_HERE, "COMMIT"));
+  if (!commit)
+    return false;
+  return commit.Run();
+}
+
+bool Connection::Execute(const char* sql) {
+  if (!db_)
+    return false;
+  return sqlite3_exec(db_, sql, NULL, NULL, NULL) == SQLITE_OK;
+}
+
+bool Connection::ExecuteWithTimeout(const char* sql, base::TimeDelta timeout) {
+  if (!db_)
+    return false;
+
+  ScopedBusyTimeout busy_timeout(db_);
+  busy_timeout.SetTimeout(timeout);
+  return sqlite3_exec(db_, sql, NULL, NULL, NULL) == SQLITE_OK;
+}
+
+bool Connection::HasCachedStatement(const StatementID& id) const {
+  return statement_cache_.find(id) != statement_cache_.end();
+}
+
+scoped_refptr<Connection::StatementRef> Connection::GetCachedStatement(
+    const StatementID& id,
+    const char* sql) {
+  CachedStatementMap::iterator i = statement_cache_.find(id);
+  if (i != statement_cache_.end()) {
+    // Statement is in the cache. It should still be active (we're the only
+    // one invalidating cached statements, and we'll remove it from the cache
+    // if we do that. Make sure we reset it before giving out the cached one in
+    // case it still has some stuff bound.
+    DCHECK(i->second->is_valid());
+    sqlite3_reset(i->second->stmt());
+    return i->second;
+  }
+
+  scoped_refptr<StatementRef> statement = GetUniqueStatement(sql);
+  if (statement->is_valid())
+    statement_cache_[id] = statement;  // Only cache valid statements.
+  return statement;
+}
+
+scoped_refptr<Connection::StatementRef> Connection::GetUniqueStatement(
+    const char* sql) {
+  if (!db_)
+    return new StatementRef(this, NULL);  // Return inactive statement.
+
+  sqlite3_stmt* stmt = NULL;
+  if (sqlite3_prepare_v2(db_, sql, -1, &stmt, NULL) != SQLITE_OK) {
+    // Treat this as non-fatal, it can occur in a number of valid cases, and
+    // callers should be doing their own error handling.
+    DLOG(WARNING) << "SQL compile error " << GetErrorMessage();
+    return new StatementRef(this, NULL);
+  }
+  return new StatementRef(this, stmt);
+}
+
+bool Connection::DoesTableExist(const char* table_name) const {
+  // GetUniqueStatement can't be const since statements may modify the
+  // database, but we know ours doesn't modify it, so the cast is safe.
+  Statement statement(const_cast<Connection*>(this)->GetUniqueStatement(
+      "SELECT name FROM sqlite_master "
+      "WHERE type='table' AND name=?"));
+  if (!statement)
+    return false;
+  statement.BindString(0, table_name);
+  return statement.Step();  // Table exists if any row was returned.
+}
+
+bool Connection::DoesColumnExist(const char* table_name,
+                                 const char* column_name) const {
+  std::string sql("PRAGMA TABLE_INFO(");
+  sql.append(table_name);
+  sql.append(")");
+
+  // Our SQL is non-mutating, so this cast is OK.
+  Statement statement(const_cast<Connection*>(this)->GetUniqueStatement(
+      sql.c_str()));
+  if (!statement)
+    return false;
+
+  while (statement.Step()) {
+    if (!statement.ColumnString(1).compare(column_name))
+      return true;
+  }
+  return false;
+}
+
+int64 Connection::GetLastInsertRowId() const {
+  if (!db_) {
+    NOTREACHED();
+    return 0;
+  }
+  return sqlite3_last_insert_rowid(db_);
+}
+
+int Connection::GetLastChangeCount() const {
+  if (!db_) {
+    NOTREACHED();
+    return 0;
+  }
+  return sqlite3_changes(db_);
+}
+
+int Connection::GetErrorCode() const {
+  if (!db_)
+    return SQLITE_ERROR;
+  return sqlite3_errcode(db_);
+}
+
+int Connection::GetLastErrno() const {
+  if (!db_)
+    return -1;
+
+  int err = 0;
+  if (SQLITE_OK != sqlite3_file_control(db_, NULL, SQLITE_LAST_ERRNO, &err))
+    return -2;
+
+  return err;
+}
+
+const char* Connection::GetErrorMessage() const {
+  if (!db_)
+    return "sql::Connection has no connection.";
+  return sqlite3_errmsg(db_);
+}
+
+bool Connection::OpenInternal(const std::string& file_name) {
+  if (db_) {
+    NOTREACHED() << "sql::Connection is already open.";
+    return false;
+  }
+
+  int err = sqlite3_open(file_name.c_str(), &db_);
+  if (err != SQLITE_OK) {
+    OnSqliteError(err, NULL);
+    db_ = NULL;
+    return false;
+  }
+
+  // Enable extended result codes to provide more color on I/O errors.
+  // Not having extended result codes is not a fatal problem, as
+  // Chromium code does not attempt to handle I/O errors anyhow.  The
+  // current implementation always returns SQLITE_OK, the DCHECK is to
+  // quickly notify someone if SQLite changes.
+  err = sqlite3_extended_result_codes(db_, 1);
+  DCHECK_EQ(err, SQLITE_OK) << "Could not enable extended result codes";
+
+  // If indicated, lock up the database before doing anything else, so
+  // that the following code doesn't have to deal with locking.
+  // TODO(shess): This code is brittle.  Find the cases where code
+  // doesn't request |exclusive_locking_| and audit that it does the
+  // right thing with SQLITE_BUSY, and that it doesn't make
+  // assumptions about who might change things in the database.
+  // http://crbug.com/56559
+  if (exclusive_locking_) {
+    // TODO(shess): This should probably be a full CHECK().  Code
+    // which requests exclusive locking but doesn't get it is almost
+    // certain to be ill-tested.
+    if (!Execute("PRAGMA locking_mode=EXCLUSIVE"))
+      NOTREACHED() << "Could not set locking mode: " << GetErrorMessage();
+  }
+
+  if (page_size_ != 0) {
+    // Enforce SQLite restrictions on |page_size_|.
+    DCHECK(!(page_size_ & (page_size_ - 1)))
+        << " page_size_ " << page_size_ << " is not a power of two.";
+    static const int kSqliteMaxPageSize = 32768;  // from sqliteLimit.h
+    DCHECK_LE(page_size_, kSqliteMaxPageSize);
+    const std::string sql = StringPrintf("PRAGMA page_size=%d", page_size_);
+    if (!ExecuteWithTimeout(sql.c_str(), kBusyTimeout))
+      NOTREACHED() << "Could not set page size: " << GetErrorMessage();
+  }
+
+  if (cache_size_ != 0) {
+    const std::string sql = StringPrintf("PRAGMA cache_size=%d", cache_size_);
+    if (!ExecuteWithTimeout(sql.c_str(), kBusyTimeout))
+      NOTREACHED() << "Could not set cache size: " << GetErrorMessage();
+  }
+
+  return true;
+}
+
+void Connection::DoRollback() {
+  Statement rollback(GetCachedStatement(SQL_FROM_HERE, "ROLLBACK"));
+  if (rollback)
+    rollback.Run();
+}
+
+void Connection::StatementRefCreated(StatementRef* ref) {
+  DCHECK(open_statements_.find(ref) == open_statements_.end());
+  open_statements_.insert(ref);
+}
+
+void Connection::StatementRefDeleted(StatementRef* ref) {
+  StatementRefSet::iterator i = open_statements_.find(ref);
+  if (i == open_statements_.end())
+    NOTREACHED();
+  else
+    open_statements_.erase(i);
+}
+
+void Connection::ClearCache() {
+  statement_cache_.clear();
+
+  // The cache clear will get most statements. There may be still be references
+  // to some statements that are held by others (including one-shot statements).
+  // This will deactivate them so they can't be used again.
+  for (StatementRefSet::iterator i = open_statements_.begin();
+       i != open_statements_.end(); ++i)
+    (*i)->Close();
+}
+
+int Connection::OnSqliteError(int err, sql::Statement *stmt) {
+  if (error_delegate_.get())
+    return error_delegate_->OnError(err, this, stmt);
+  // The default handling is to assert on debug and to ignore on release.
+  NOTREACHED() << GetErrorMessage();
+  return err;
+}
+
+}  // namespace sql