unit ScFileProviders;

interface

uses
  Windows, Classes, SysUtils, ConstMethodUnit, ADODB, ScFileArchiver, Forms;

type
  EScFileProvider = class(Exception);

  TScConnection = class(TObject)
  private
    FRefCount: Integer;
//    FFileName: string;
    FConnection: TADOConnection;
    FFileArchiver: TScMDBArchiver;
    FIsNew: Boolean;
    FID: Integer;
    function GetFileName: string;
  public
    constructor Create;
    destructor Destroy; override;
    property ID: Integer read FID;
    property RefCount: Integer read FRefCount;
    property Connection: TADOConnection read FConnection;
    property FileName: string read GetFileName;
    property FileArchiver: TScMDBArchiver read FFileArchiver;
    property IsNew: Boolean read FIsNew;
  end;

  TScFileType = (ftProject, ftRationLib, ftFeeRate, ftUnitPrice);

  TScArchiverClass = class of TScMDBArchiver;

  TScFileProvider = class(TObject)
  private
    FConnections: TList;
    FFileType: TScFileType;
    FTemplateFileName: string;
    function GetArchiverClass: TScArchiverClass;
    function GetConnection(ID: Integer): TScConnection;
    function AddConnection(AFileName: string): TScConnection;
    function FindConnection(AFileName: string): TScConnection;
    procedure SetFileType(const Value: TScFileType);
    procedure SetTemplateFileName(const Value: string);
    procedure Clear;
    function GetNewID: Integer;
  public
    constructor Create;
    destructor Destroy; override;
    function New: Integer;
    function Open(AFileName: string): Integer;
    function Close(AFileName: string): Boolean; overload;
    function Close(AID: Integer): Boolean; overload;
    function Save(AFileName: string): Boolean; overload;
    function Save(AID: Integer): Boolean; overload;
    function SaveAs(AFileName: string; ANewFileName: string): Boolean; overload;
    function SaveAs(AID: Integer; ANewFileName: string): Boolean; overload;
    function Refresh(AID: Integer): Boolean; overload;
    function Refresh(AFileName: string): Boolean; overload;
    function IndexByName(AFileName: string): TScConnection;
    property Connection[ID: Integer]: TScConnection read GetConnection;
    property FileType: TScFileType read FFileType write SetFileType;
    property TemplateFileName: string read FTemplateFileName write SetTemplateFileName;
  end;

var
  ProjProvider: TScFileProvider;
  FeeRateProvider: TScFileProvider;
  UnitPriceProvider: TScFileProvider;

implementation

uses
  ScConfig;

{ TScConnection }

constructor TScConnection.Create;
begin
  FRefCount := 0;
//  FFileName := '';
  FConnection := nil;
  FFileArchiver := nil;
  FIsNew := False;
end;

destructor TScConnection.Destroy;
begin

  inherited;
end;

function TScConnection.GetFileName: string;
begin
  if FFileArchiver <> nil then
    Result := FFileArchiver.FileName;
end;

{ TScFileProvider }

function TScFileProvider.AddConnection(AFileName: string): TScConnection;
begin
  Result := nil;
  Result := TScConnection.Create;
  Result.FConnection := TADOConnection.Create(nil);
  Result.FFileArchiver := GetArchiverClass.Create;
  Result.FFileArchiver.Connection := Result.FConnection;
  Result.FFileArchiver.FileName := AFileName;
  try
    if not Result.FFileArchiver.OpenFile then
    begin
      FreeAndNil(Result);
      Exit;
    end;
  except
    Result := nil;
    MessageError(0, Format('无法打开文件[%s]！', [AFilename]));
  end;
  if Result <> nil then
  begin
    FConnections.Add(Result);
    Result.FID := GetNewID + 1;
    Inc(Result.FRefCount);
  end;
end;

function TScFileProvider.Close(AFileName: string): Boolean;
var
  Con: TScConnection;
begin
  Result := True;
  Con := FindConnection(AFileName);
  if Con <> nil then
  begin
    if Con.RefCount > 1 then
      Dec(Con.FRefCount)
    else
    begin
      FConnections.Remove(Con);
      Con.FileArchiver.CloseFile;
      Con.Connection.Connected := False;
      Con.Connection.Free;
      Con.FileArchiver.Free;
      Con.Free;
    end;
  end;
end;

function TScFileProvider.Close(AID: Integer): Boolean;
var
  Con: TScConnection;
begin
  Result := True;
  Con := Connection[AID];
  if Con <> nil then
  begin
    if Con.RefCount > 1 then
      Dec(Con.FRefCount)
    else
    begin
      FConnections.Remove(Con);
      Con.FileArchiver.CloseFile;
      Con.Connection.Connected := False;
      Con.Connection.Free;
      Con.FileArchiver.Free;
      Con.Free;
    end;
  end;
end;

constructor TScFileProvider.Create;
begin
  FConnections := TList.Create;
end;

destructor TScFileProvider.Destroy;
begin
  Clear;
  FConnections.Free;
  inherited;
end;

function TScFileProvider.FindConnection(AFileName: string): TScConnection;
var
  I: Integer;
begin
  Result := nil;
  for I := 0 to FConnections.Count - 1 do
  begin
    if SameText(AFileName, TScConnection(FConnections[I]).FileName) then
    begin
      Result := TScConnection(FConnections[I]);
      Break;
    end;
  end;
end;

function TScFileProvider.GetConnection(ID: Integer): TScConnection;
var
  I: Integer;
begin
  Result := nil;
  for I := 0 to FConnections.Count - 1 do
  begin
    if ID = TScConnection(FConnections[I]).FID then
    begin
      Result := TScConnection(FConnections[I]);
      Break;
    end;
  end;
end;
// 这方法不行，如果某个文件被关闭了，会从List中删除，这时会有错误。
{begin
  Result := nil;
  if (ID >= 0) and (ID < FConnections.Count) then
  begin
    Result := TScConnection(FConnections.Items[ID]);
    if not (Result is TScConnection) then
      Result := nil;
  end
  else
    Result := nil;
end;}

function TScFileProvider.Open(AFileName: string): Integer;
var
  Con: TScConnection;
begin
  Result := -1;
  Con := FindConnection(AFileName);
  if Con = nil then
  begin
    Con := AddConnection(AFileName);
    if Con = nil then
    begin
      Result := -1;
      Exit;
    end;
    Con.Connection.LoginPrompt := False;
    Con.Connection.Connected := True;
  end
  else
    Inc(Con.FRefCount);
  Result := Con.ID;
end;

function TScFileProvider.Save(AFileName: string): Boolean;
var
  Con: TScConnection;
begin
  Result := False;
  Con := FindConnection(AFileName);
  if Con <> nil then
  begin
    Result := Con.FileArchiver.Save;
  end;
end;

function TScFileProvider.Save(AID: Integer): Boolean;
var
  Con: TScConnection;
begin
  Result := False;
  Con := Connection[AID];
  if Con <> nil then
  begin
    Result := Con.FileArchiver.Save;
  end;
end;

function TScFileProvider.SaveAs(AFileName: string;
  ANewFileName: string): Boolean;
var
  Con: TScConnection;
begin
  Result := False;
  Con := FindConnection(AFileName);
  if Con <> nil then
  begin
    Result := Con.FileArchiver.SaveTo(ANewFileName);
  end;
end;

function TScFileProvider.SaveAs(AID: Integer;
  ANewFileName: string): Boolean;
var
  Con: TScConnection;
begin
  Result := False;
  Con := Connection[AID];
  if Con <> nil then
  begin
    Result := Con.FileArchiver.SaveTo(ANewFileName);
  end;
end;

procedure TScFileProvider.SetFileType(const Value: TScFileType);
begin
  FFileType := Value;
end;

function TScFileProvider.GetArchiverClass: TScArchiverClass;
begin
  Result := TScMDBArchiver;
  case FFileType of
    ftProject:
      Result := TScProjectFileArchiver;
    ftRationLib:
      Result := TScRationLibArchiver;
    ftFeeRate:
      Result := TScFeeRateFileArchiver;
    ftUnitPrice:
      Result := TScUnitPriceFileArchiver;
  end;
end;

function TScFileProvider.New: Integer;
var
  Con: TScConnection;
begin
  Result := -1;
  if not FileExists(FTemplateFileName) then
  begin
    raise EScFileProvider.Create('文件系统故障，无法创建新文件！');
  end;
  Con := AddConnection(FTemplateFileName);
  Con.Connection.LoginPrompt := False;
  Con.Connection.Connected := True;
  Result := Con.ID;
end;

procedure TScFileProvider.SetTemplateFileName(const Value: string);
begin
  FTemplateFileName := Value;
end;

procedure TScFileProvider.Clear;
var
  I: Integer;
  Con: TScConnection;
begin
  for I := 0 to FConnections.Count - 1 do
  begin
    Con := TScConnection(FConnections[I]);
    if Con <> nil then
    begin
      Con.FileArchiver.CloseFile;
      Con.Connection.Connected := False;
      Con.Connection.Free;
      Con.FileArchiver.Free;
      Con.Free;
    end;
  end;
  FConnections.Clear;
end;

function TScFileProvider.IndexByName(AFileName: string): TScConnection;
begin
  Result := FindConnection(AFileName);
end;

function TScFileProvider.Refresh(AID: Integer): Boolean;
var
  Con: TScConnection;
begin
  Result := False;
  Con := Connection[AID];
  if Con <> nil then
  begin
    Result := Con.FileArchiver.Refresh;
  end;
end;

function TScFileProvider.Refresh(AFileName: string): Boolean;
var
  Con: TScConnection;
begin
  Result := False;
  Con := FindConnection(AFileName);
  if Con <> nil then
  begin
    Result := Con.FileArchiver.Refresh;
  end;
end;

function TScFileProvider.GetNewID: Integer;
var
  I, iMaxID: Integer;
begin
  iMaxID := 0;
  for I := 0 to FConnections.Count - 1 do
  begin
    if iMaxID < TScConnection(FConnections[I]).ID then
      iMaxID := TScConnection(FConnections[I]).ID;
  end;
  Result := iMaxID;
end;

initialization
  ProjProvider := TScFileProvider.Create;
  ProjProvider.FFileType := ftProject;
//  这里ConfigInfo还没有加载，不行
//  ProjProvider.TemplateFileName := ConfigInfo.ProjFileTemplate;//ExtractFilePath(Application.ExeName) + 'Data\MainTemplate.dat';

  FeeRateProvider := TScFileProvider.Create;
  FeeRateProvider.FFileType := ftFeeRate;

  UnitPriceProvider := TScFileProvider.Create;
  UnitPriceProvider.FFileType := ftUnitPrice;

finalization
  ProjProvider.Free;
  FeeRateProvider.Free;
  UnitPriceProvider.Free;

end.