/********************************************************
* ADO.NET 2.0 Data Provider for SQLite Version 3.X
* Written by Robert Simpson (robert@blackcastlesoft.com)
*
* Released to the public domain, use at your own risk!
********************************************************/
namespace System.Data.SQLite
{
using System;
using System.Data;
using System.Runtime.InteropServices;
using System.Collections.Generic;
/// <summary>
/// This internal class provides the foundation of SQLite support. It defines all the abstract members needed to implement
/// a SQLite data provider, and inherits from SQLiteConvert which allows for simple translations of string to and from SQLite.
/// </summary>
internal abstract class SQLiteBase : SQLiteConvert, IDisposable
{
internal SQLiteBase(SQLiteDateFormats fmt)
: base(fmt) {}
/// <summary>
/// Returns a string representing the active version of SQLite
/// </summary>
internal abstract string Version { get; }
/// <summary>
/// Returns the number of changes the last executing insert/update caused.
/// </summary>
internal abstract int Changes { get; }
/// <summary>
/// Opens a database.
/// </summary>
/// <remarks>
/// Implementers should call SQLiteFunction.BindFunctions() and save the array after opening a connection
/// to bind all attributed user-defined functions and collating sequences to the new connection.
/// </remarks>
/// <param name="strFilename">The filename of the database to open. SQLite automatically creates it if it doesn't exist.</param>
internal abstract void Open(string strFilename);
/// <summary>
/// Closes the currently-open database.
/// </summary>
/// <remarks>
/// After the database has been closed implemeters should call SQLiteFunction.UnbindFunctions() to deallocate all interop allocated
/// memory associated with the user-defined functions and collating sequences tied to the closed connection.
/// </remarks>
internal abstract void Close();
/// <summary>
/// Sets the busy timeout on the connection. SQLiteCommand will call this before executing any command.
/// </summary>
/// <param name="nTimeoutMS">The number of milliseconds to wait before returning SQLITE_BUSY</param>
internal abstract void SetTimeout(int nTimeoutMS);
/// <summary>
/// Quick execute of a SQL command. This is only executed internally, usually by SQLiteConnection when the connection
/// is first opened to set the necessary startup pragmas.
/// </summary>
/// <param name="strSql">The SQL command text to execute</param>
internal abstract void Execute(string strSql);
/// <summary>
/// Returns the text of the last error issued by SQLite
/// </summary>
/// <returns></returns>
internal abstract string SQLiteLastError();
/// <summary>
/// Prepares a SQL statement for execution.
/// </summary>
/// <param name="strSql">The SQL command text to prepare</param>
/// <param name="nParamStart">When preparing multiple statements that are tied together into a single command,
/// this value should be initialized to 0 for the first statement prepared. On return from this function, the
/// variable will automatically be incremented by 1 for each unnamed parameter that occurred in the statement.
/// When implementing this function, one need only pass the nParamStart variable by reference to the SQLiteStatement()
/// constructor. SQLiteStatement will take care of it.</param>
/// <param name="strRemain">The remainder of the statement that was not processed. Each call to prepare parses the
/// SQL up to to either the end of the text or to the first semi-colon delimiter. The remaining text is returned
/// here for a subsequent call to Prepare() until all the text has been processed.</param>
/// <returns>Returns an initialized SQLiteStatement.</returns>
internal abstract SQLiteStatement Prepare(string strSql, ref int nParamStart, out string strRemain);
/// <summary>
/// Steps through a prepared statement.
/// </summary>
/// <param name="stmt">The SQLiteStatement to step through</param>
/// <returns>True if a row was returned, False if not.</returns>
internal abstract bool Step(SQLiteStatement stmt);
/// <summary>
/// Finalizes a prepared statement.
/// </summary>
/// <param name="stmt">The statement to finalize</param>
internal abstract void FinalizeStatement(SQLiteStatement stmt);
/// <summary>
/// Resets a prepared statement so it can be executed again. If the error returned is SQLITE_SCHEMA,
/// transparently attempt to rebuild the SQL statement and throw an error if that was not possible.
/// </summary>
/// <param name="stmt">The statement to reset</param>
/// <returns>Returns -1 if the schema changed while resetting, 0 if the reset was sucessful or 6 (SQLITE_LOCKED) if the reset failed due to a lock</returns>
internal abstract int Reset(SQLiteStatement stmt);
internal abstract void Cancel();
/// <summary>
/// An interop-specific function, this call sets an internal flag in the sqlite.interop.dll which causes all column names
/// of subsequently-prepared statements to return in Database.Table.Column format, ignoring all aliases that may have been applied
/// to tables or columns in a resultset.
/// </summary>
/// <remarks>
/// All statements prepared on this connection after this flag is changed are affected. Existing statements are not.
/// </remarks>
/// <param name="bOn">Set to True to enable real column names, false to disable them.</param>
internal abstract void SetRealColNames(bool bOn);
internal abstract void Bind_Double(SQLiteStatement stmt, int index, double value);
internal abstract void Bind_Int32(SQLiteStatement stmt, int index, Int32 value);
internal abstract void Bind_Int64(SQLiteStatement stmt, int index, Int64 value);
internal abstract void Bind_Text(SQLiteStatement stmt, int index, string value);
internal abstract void Bind_Blob(SQLiteStatement stmt, int index, byte[] blobData);
internal abstract void Bind_DateTime(SQLiteStatement stmt, int index, DateTime dt);
internal abstract void Bind_Null(SQLiteStatement stmt, int index);
internal abstract int Bind_ParamCount(SQLiteStatement stmt);
internal abstract string Bind_ParamName(SQLiteStatement stmt, int index);
internal abstract int Bind_ParamIndex(SQLiteStatement stmt, string paramName);
internal abstract int ColumnCount(SQLiteStatement stmt);
internal abstract string ColumnName(SQLiteStatement stmt, int index);
internal abstract string ColumnType(SQLiteStatement stmt, int index, out TypeAffinity nAffinity);
internal abstract int ColumnIndex(SQLiteStatement stmt, string columnName);
internal abstract double GetDouble(SQLiteStatement stmt, int index);
internal abstract Int32 GetInt32(SQLiteStatement stmt, int index);
internal abstract Int64 GetInt64(SQLiteStatement stmt, int index);
internal abstract string GetText(SQLiteStatement stmt, int index);
internal abstract long GetBytes(SQLiteStatement stmt, int index, int nDataoffset, byte[] bDest, int nStart, int nLength);
internal abstract long GetChars(SQLiteStatement stmt, int index, int nDataoffset, char[] bDest, int nStart, int nLength);
internal abstract DateTime GetDateTime(SQLiteStatement stmt, int index);
internal abstract bool IsNull(SQLiteStatement stmt, int index);
/// <summary>
/// Helper function to retrieve a column of data from an active statement.
/// </summary>
/// <param name="stmt">The statement being step()'d through</param>
/// <param name="index">The column index to retrieve</param>
/// <param name="typ">The type of data contained in the column. If Uninitialized, this function will retrieve the datatype information.</param>
/// <returns>Returns the data in the column</returns>
internal virtual object GetValue(SQLiteStatement stmt, int index, ref SQLiteType typ)
{
if (typ.Affinity == 0) typ = SQLiteConvert.ColumnToType(stmt, index);
if (IsNull(stmt, index)) return DBNull.Value;
Type t = SQLiteConvert.SQLiteTypeToType(typ);
if (t == typeof(byte[]))
{
int n = (int)GetBytes(stmt, index, 0, null, 0, 0);
byte[] b = new byte[n];
GetBytes(stmt, index, 0, b, 0, n);
return b;
}
return Convert.ChangeType(GetText(stmt, index), t, null);
}
internal abstract int CreateCollation(string strCollation, SQLiteCollation func);
internal abstract int CreateFunction(string strFunction, int nArgs, SQLiteCallback func, SQLiteCallback funcstep, SQLiteCallback funcfinal);
internal abstract void FreeFunction(int nCookie);
internal abstract int AggregateCount(int context);
internal abstract int AggregateContext(int context);
internal abstract long GetParamValueBytes(int ptr, int nDataOffset, byte[] bDest, int nStart, int nLength);
internal abstract double GetParamValueDouble(int ptr);
internal abstract int GetParamValueInt32(int ptr);
internal abstract Int64 GetParamValueInt64(int ptr);
internal abstract string GetParamValueText(int ptr);
internal abstract TypeAffinity GetParamValueType(int ptr);
internal abstract void ReturnBlob(int context, byte[] value);
internal abstract void ReturnDouble(int context, double value);
internal abstract void ReturnError(int context, string value);
internal abstract void ReturnInt32(int context, Int32 value);
internal abstract void ReturnInt64(int context, Int64 value);
internal abstract void ReturnNull(int context);
internal abstract void ReturnText(int context, string value);
protected virtual void Dispose(bool bDisposing)
{
}
public void Dispose()
{
Dispose(true);
GC.SuppressFinalize(this);
}
}
}