fpc/fcl/xml/xmlcfg.pp

{
    $Id$
    This file is part of the Free Pascal run time library.
    Copyright (c)  1999 Sebastian Guenther, sguenther@gmx.de

    Implementation of TXMLConfig class
    
    See the file COPYING.FPC, included in this distribution,
    for details about the copyright.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

 **********************************************************************}

{
  TXMLConfig enables applications to use XML files for storing their
  configuration data
}

{$MODE objfpc}

unit xmlcfg;

interface
uses DOM, xmlread, xmlwrite;

type

  {"APath" is the path and name of a value: A XML configuration file is
   hierarchical. "/" is the path delimiter, the part after the last "/"
   is the name of the value. The path components will be mapped to XML
   elements, the name will be an element attribute.}

  TXMLConfig = class
  protected
    doc: TXMLDocument;
    FileName: String;
  public
    constructor Create(AFileName: String);
    destructor Destroy; override;
    procedure Flush;    // Writes the XML file
    function  GetValue(APath, ADefault: String): String;
    function  GetValue(APath: String; ADefault: Integer): Integer;
    function  GetValue(APath: String; ADefault: Boolean): Boolean;
    procedure SetValue(APath, AValue: String);
    procedure SetValue(APath: String; AValue: Integer);
    procedure SetValue(APath: String; AValue: Boolean);
  end;


// =======================================================

implementation

uses sysutils;


constructor TXMLConfig.Create(AFileName: String);
var
  f: File;
  cfg: TDOMElement;
begin
  FileName := AFileName;
  Assign(f, AFileName);
  {$I-}
  Reset(f, 1);
  {$I+}
  if IOResult = 0 then begin
    try
      ReadXMLFile(doc, f);
    except
      on e: EXMLReadError do
        WriteLn(StdErr, 'Warning: XML config parsing error: ', e.Message);
    end;
    Close(f);
  end;

  if doc = nil then
    doc := TXMLDocument.Create;

  cfg :=TDOMElement(doc.FindNode('CONFIG'));
  if cfg = nil then begin
    cfg := doc.CreateElement('CONFIG');
    doc.AppendChild(cfg);
  end;
  doc.SetDocumentElement(cfg);
end;

destructor TXMLConfig.Destroy;
begin
  Flush;
  inherited Destroy;
end;

procedure TXMLConfig.Flush;
var
  f: Text;
begin
  Assign(f, FileName);
  Rewrite(f);
  WriteXMLFile(doc, f);
  Close(f);
end;

function TXMLConfig.GetValue(APath, ADefault: String): String;
var
  node, subnode, attr: TDOMNode;
  i: Integer;
  name: String;
begin
  node := doc.DocumentElement;
  while True do begin
    i := Pos('/', APath);
    if i = 0 then break;
    name := Copy(APath, 1, i - 1);
    APath := Copy(APath, i + 1, Length(APath));
    subnode := node.FindNode(name);
    if subnode = nil then begin
      Result := ADefault;
      exit;
    end;
    node := subnode;
  end;
  attr := node.Attributes.GetNamedItem(APath);
  if attr = nil then
    Result := ADefault
  else
    Result := attr.NodeValue;
end;

function TXMLConfig.GetValue(APath: String; ADefault: Integer): Integer;
begin
  Result := StrToInt(GetValue(APath, IntToStr(ADefault)));
end;

function TXMLConfig.GetValue(APath: String; ADefault: Boolean): Boolean;
var
  s: String;
begin
  if ADefault then s := 'True'
  else s := 'False';
  s := GetValue(APath, s);
  if UpperCase(s) = 'TRUE' then Result := True
  else if UpperCase(s) = 'FALSE' then Result := False
  else Result := ADefault;
end;

procedure TXMLConfig.SetValue(APath, AValue: String);
var
  node, subnode, attr: TDOMNode;
  i: Integer;
  name: String;
begin
  node := doc.DocumentElement;
  while True do begin
    i := Pos('/', APath);
    if i = 0 then break;
    name := Copy(APath, 1, i - 1);
    APath := Copy(APath, i + 1, Length(APath));
    subnode := node.FindNode(name);
    if subnode = nil then begin
      subnode := doc.CreateElement(name);
      node.AppendChild(subnode);
    end;
    node := subnode;
  end;
  attr := node.Attributes.GetNamedItem(APath);
  if attr = nil then begin
    attr := doc.CreateAttribute(APath);
    node.Attributes.SetNamedItem(attr);
  end;
  attr.NodeValue := AValue;
end;

procedure TXMLConfig.SetValue(APath: String; AValue: Integer);
begin
  SetValue(APath, IntToStr(AValue));
end;

procedure TXMLConfig.SetValue(APath: String; AValue: Boolean);
begin
  if AValue then SetValue(APath, 'True')
  else SetValue(APath, 'False');
end;


end.


{
  $Log$
  Revision 1.3  1999-07-25 16:24:13  michael
  + Fixes from Sebastiam Guenther - more error-proof

  Revision 1.2  1999/07/09 21:05:50  michael
  + fixes from Guenther Sebastian

  Revision 1.1  1999/07/09 08:35:09  michael
  + Initial implementation by Sebastian Guenther

}