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Unified Diff: app/sql/connection.h

Issue 7353026: Move app/sql/* files to sql/ directory. (Closed) Base URL: svn://svn.chromium.org/chrome/trunk/src
Patch Set: rebased Created 9 years, 5 months ago
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Index: app/sql/connection.h
diff --git a/app/sql/connection.h b/app/sql/connection.h
deleted file mode 100644
index d82b8b847796716dd8e0fa96320c82d640ae2454..0000000000000000000000000000000000000000
--- a/app/sql/connection.h
+++ /dev/null
@@ -1,387 +0,0 @@
-// 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.
-
-#ifndef APP_SQL_CONNECTION_H_
-#define APP_SQL_CONNECTION_H_
-#pragma once
-
-#include <map>
-#include <set>
-#include <string>
-
-#include "base/basictypes.h"
-#include "base/memory/ref_counted.h"
-#include "base/time.h"
-
-class FilePath;
-struct sqlite3;
-struct sqlite3_stmt;
-
-namespace sql {
-
-class Statement;
-
-// Uniquely identifies a statement. There are two modes of operation:
-//
-// - In the most common mode, you will use the source file and line number to
-// identify your statement. This is a convienient way to get uniqueness for
-// a statement that is only used in one place. Use the SQL_FROM_HERE macro
-// to generate a StatementID.
-//
-// - In the "custom" mode you may use the statement from different places or
-// need to manage it yourself for whatever reason. In this case, you should
-// make up your own unique name and pass it to the StatementID. This name
-// must be a static string, since this object only deals with pointers and
-// assumes the underlying string doesn't change or get deleted.
-//
-// This object is copyable and assignable using the compiler-generated
-// operator= and copy constructor.
-class StatementID {
- public:
- // Creates a uniquely named statement with the given file ane line number.
- // Normally you will use SQL_FROM_HERE instead of calling yourself.
- StatementID(const char* file, int line)
- : number_(line),
- str_(file) {
- }
-
- // Creates a uniquely named statement with the given user-defined name.
- explicit StatementID(const char* unique_name)
- : number_(-1),
- str_(unique_name) {
- }
-
- // This constructor is unimplemented and will generate a linker error if
- // called. It is intended to try to catch people dynamically generating
- // a statement name that will be deallocated and will cause a crash later.
- // All strings must be static and unchanging!
- explicit StatementID(const std::string& dont_ever_do_this);
-
- // We need this to insert into our map.
- bool operator<(const StatementID& other) const;
-
- private:
- int number_;
- const char* str_;
-};
-
-#define SQL_FROM_HERE sql::StatementID(__FILE__, __LINE__)
-
-class Connection;
-
-// ErrorDelegate defines the interface to implement error handling and recovery
-// for sqlite operations. This allows the rest of the classes to return true or
-// false while the actual error code and causing statement are delivered using
-// the OnError() callback.
-// The tipical usage is to centralize the code designed to handle database
-// corruption, low-level IO errors or locking violations.
-class ErrorDelegate : public base::RefCounted<ErrorDelegate> {
- public:
- ErrorDelegate();
-
- // |error| is an sqlite result code as seen in sqlite\preprocessed\sqlite3.h
- // |connection| is db connection where the error happened and |stmt| is
- // our best guess at the statement that triggered the error. Do not store
- // these pointers.
- //
- // |stmt| MAY BE NULL if there is no statement causing the problem (i.e. on
- // initialization).
- //
- // If the error condition has been fixed an the original statement succesfuly
- // re-tried then returning SQLITE_OK is appropiate; otherwise is recomended
- // that you return the original |error| or the appropiae error code.
- virtual int OnError(int error, Connection* connection, Statement* stmt) = 0;
-
- protected:
- friend class base::RefCounted<ErrorDelegate>;
-
- virtual ~ErrorDelegate();
-};
-
-class Connection {
- private:
- class StatementRef; // Forward declaration, see real one below.
-
- public:
- // The database is opened by calling Open[InMemory](). Any uncommitted
- // transactions will be rolled back when this object is deleted.
- Connection();
- ~Connection();
-
- // Pre-init configuration ----------------------------------------------------
-
- // Sets the page size that will be used when creating a new database. This
- // must be called before Init(), and will only have an effect on new
- // databases.
- //
- // From sqlite.org: "The page size must be a power of two greater than or
- // equal to 512 and less than or equal to SQLITE_MAX_PAGE_SIZE. The maximum
- // value for SQLITE_MAX_PAGE_SIZE is 32768."
- void set_page_size(int page_size) { page_size_ = page_size; }
-
- // Sets the number of pages that will be cached in memory by sqlite. The
- // total cache size in bytes will be page_size * cache_size. This must be
- // called before Open() to have an effect.
- void set_cache_size(int cache_size) { cache_size_ = cache_size; }
-
- // Call to put the database in exclusive locking mode. There is no "back to
- // normal" flag because of some additional requirements sqlite puts on this
- // transaition (requires another access to the DB) and because we don't
- // actually need it.
- //
- // Exclusive mode means that the database is not unlocked at the end of each
- // transaction, which means there may be less time spent initializing the
- // next transaction because it doesn't have to re-aquire locks.
- //
- // This must be called before Open() to have an effect.
- void set_exclusive_locking() { exclusive_locking_ = true; }
-
- // Sets the object that will handle errors. Recomended that it should be set
- // before calling Open(). If not set, the default is to ignore errors on
- // release and assert on debug builds.
- void set_error_delegate(ErrorDelegate* delegate) {
- error_delegate_ = delegate;
- }
-
- // Initialization ------------------------------------------------------------
-
- // Initializes the SQL connection for the given file, returning true if the
- // file could be opened. You can call this or OpenInMemory.
- bool Open(const FilePath& path);
-
- // Initializes the SQL connection for a temporary in-memory database. There
- // will be no associated file on disk, and the initial database will be
- // empty. You can call this or Open.
- bool OpenInMemory();
-
- // Returns trie if the database has been successfully opened.
- bool is_open() const { return !!db_; }
-
- // Closes the database. This is automatically performed on destruction for
- // you, but this allows you to close the database early. You must not call
- // any other functions after closing it. It is permissable to call Close on
- // an uninitialized or already-closed database.
- void Close();
-
- // Pre-loads the first <cache-size> pages into the cache from the file.
- // If you expect to soon use a substantial portion of the database, this
- // is much more efficient than allowing the pages to be populated organically
- // since there is no per-page hard drive seeking. If the file is larger than
- // the cache, the last part that doesn't fit in the cache will be brought in
- // organically.
- //
- // This function assumes your class is using a meta table on the current
- // database, as it openes a transaction on the meta table to force the
- // database to be initialized. You should feel free to initialize the meta
- // table after calling preload since the meta table will already be in the
- // database if it exists, and if it doesn't exist, the database won't
- // generally exist either.
- void Preload();
-
- // Transactions --------------------------------------------------------------
-
- // Transaction management. We maintain a virtual transaction stack to emulate
- // nested transactions since sqlite can't do nested transactions. The
- // limitation is you can't roll back a sub transaction: if any transaction
- // fails, all transactions open will also be rolled back. Any nested
- // transactions after one has rolled back will return fail for Begin(). If
- // Begin() fails, you must not call Commit or Rollback().
- //
- // Normally you should use sql::Transaction to manage a transaction, which
- // will scope it to a C++ context.
- bool BeginTransaction();
- void RollbackTransaction();
- bool CommitTransaction();
-
- // Returns the current transaction nesting, which will be 0 if there are
- // no open transactions.
- int transaction_nesting() const { return transaction_nesting_; }
-
- // Statements ----------------------------------------------------------------
-
- // Executes the given SQL string, returning true on success. This is
- // normally used for simple, 1-off statements that don't take any bound
- // parameters and don't return any data (e.g. CREATE TABLE).
- bool Execute(const char* sql);
-
- // Returns true if we have a statement with the given identifier already
- // cached. This is normally not necessary to call, but can be useful if the
- // caller has to dynamically build up SQL to avoid doing so if it's already
- // cached.
- bool HasCachedStatement(const StatementID& id) const;
-
- // Returns a statement for the given SQL using the statement cache. It can
- // take a nontrivial amount of work to parse and compile a statement, so
- // keeping commonly-used ones around for future use is important for
- // performance.
- //
- // The SQL may have an error, so the caller must check validity of the
- // statement before using it.
- //
- // The StatementID and the SQL must always correspond to one-another. The
- // ID is the lookup into the cache, so crazy things will happen if you use
- // different SQL with the same ID.
- //
- // You will normally use the SQL_FROM_HERE macro to generate a statement
- // ID associated with the current line of code. This gives uniqueness without
- // you having to manage unique names. See StatementID above for more.
- //
- // Example:
- // sql::Statement stmt(connection_.GetCachedStatement(
- // SQL_FROM_HERE, "SELECT * FROM foo"));
- // if (!stmt)
- // return false; // Error creating statement.
- scoped_refptr<StatementRef> GetCachedStatement(const StatementID& id,
- const char* sql);
-
- // Returns a non-cached statement for the given SQL. Use this for SQL that
- // is only executed once or only rarely (there is overhead associated with
- // keeping a statement cached).
- //
- // See GetCachedStatement above for examples and error information.
- scoped_refptr<StatementRef> GetUniqueStatement(const char* sql);
-
- // Info querying -------------------------------------------------------------
-
- // Returns true if the given table exists.
- bool DoesTableExist(const char* table_name) const;
-
- // Returns true if a column with the given name exists in the given table.
- bool DoesColumnExist(const char* table_name, const char* column_name) const;
-
- // Returns sqlite's internal ID for the last inserted row. Valid only
- // immediately after an insert.
- int64 GetLastInsertRowId() const;
-
- // Returns sqlite's count of the number of rows modified by the last
- // statement executed. Will be 0 if no statement has executed or the database
- // is closed.
- int GetLastChangeCount() const;
-
- // Errors --------------------------------------------------------------------
-
- // Returns the error code associated with the last sqlite operation.
- int GetErrorCode() const;
-
- // Returns the errno associated with GetErrorCode(). See
- // SQLITE_LAST_ERRNO in SQLite documentation.
- int GetLastErrno() const;
-
- // Returns a pointer to a statically allocated string associated with the
- // last sqlite operation.
- const char* GetErrorMessage() const;
-
- private:
- // Statement access StatementRef which we don't want to expose to erverybody
- // (they should go through Statement).
- friend class Statement;
-
- // Internal initialize function used by both Init and InitInMemory. The file
- // name is always 8 bits since we want to use the 8-bit version of
- // sqlite3_open. The string can also be sqlite's special ":memory:" string.
- bool OpenInternal(const std::string& file_name);
-
- // A StatementRef is a refcounted wrapper around a sqlite statement pointer.
- // Refcounting allows us to give these statements out to sql::Statement
- // objects while also optionally maintaining a cache of compiled statements
- // by just keeping a refptr to these objects.
- //
- // A statement ref can be valid, in which case it can be used, or invalid to
- // indicate that the statement hasn't been created yet, has an error, or has
- // been destroyed.
- //
- // The Connection may revoke a StatementRef in some error cases, so callers
- // should always check validity before using.
- class StatementRef : public base::RefCounted<StatementRef> {
- public:
- // Default constructor initializes to an invalid statement.
- StatementRef();
- StatementRef(Connection* connection, sqlite3_stmt* stmt);
-
- // When true, the statement can be used.
- bool is_valid() const { return !!stmt_; }
-
- // If we've not been linked to a connection, this will be NULL. Guaranteed
- // non-NULL when is_valid().
- Connection* connection() const { return connection_; }
-
- // Returns the sqlite statement if any. If the statement is not active,
- // this will return NULL.
- sqlite3_stmt* stmt() const { return stmt_; }
-
- // Destroys the compiled statement and marks it NULL. The statement will
- // no longer be active.
- void Close();
-
- private:
- friend class base::RefCounted<StatementRef>;
-
- ~StatementRef();
-
- Connection* connection_;
- sqlite3_stmt* stmt_;
-
- DISALLOW_COPY_AND_ASSIGN(StatementRef);
- };
- friend class StatementRef;
-
- // Executes a rollback statement, ignoring all transaction state. Used
- // internally in the transaction management code.
- void DoRollback();
-
- // Called by a StatementRef when it's being created or destroyed. See
- // open_statements_ below.
- void StatementRefCreated(StatementRef* ref);
- void StatementRefDeleted(StatementRef* ref);
-
- // Frees all cached statements from statement_cache_.
- void ClearCache();
-
- // Called by Statement objects when an sqlite function returns an error.
- // The return value is the error code reflected back to client code.
- int OnSqliteError(int err, Statement* stmt);
-
- // Like |Execute()|, but retries if the database is locked.
- bool ExecuteWithTimeout(const char* sql, base::TimeDelta ms_timeout);
-
- // The actual sqlite database. Will be NULL before Init has been called or if
- // Init resulted in an error.
- sqlite3* db_;
-
- // Parameters we'll configure in sqlite before doing anything else. Zero means
- // use the default value.
- int page_size_;
- int cache_size_;
- bool exclusive_locking_;
-
- // All cached statements. Keeping a reference to these statements means that
- // they'll remain active.
- typedef std::map<StatementID, scoped_refptr<StatementRef> >
- CachedStatementMap;
- CachedStatementMap statement_cache_;
-
- // A list of all StatementRefs we've given out. Each ref must register with
- // us when it's created or destroyed. This allows us to potentially close
- // any open statements when we encounter an error.
- typedef std::set<StatementRef*> StatementRefSet;
- StatementRefSet open_statements_;
-
- // Number of currently-nested transactions.
- int transaction_nesting_;
-
- // True if any of the currently nested transactions have been rolled back.
- // When we get to the outermost transaction, this will determine if we do
- // a rollback instead of a commit.
- bool needs_rollback_;
-
- // This object handles errors resulting from all forms of executing sqlite
- // commands or statements. It can be null which means default handling.
- scoped_refptr<ErrorDelegate> error_delegate_;
-
- DISALLOW_COPY_AND_ASSIGN(Connection);
-};
-
-} // namespace sql
-
-#endif // APP_SQL_CONNECTION_H_
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