{
* This Source Code Form is subject to the terms of the Mozilla Public License,
* v. 2.0. If a copy of the MPL was not distributed with this file, You can
* obtain one at http://mozilla.org/MPL/2.0/
*
* Copyright (C) 2008-2012, Peter Johnson (www.delphidabbler.com).
*
* $Rev$
* $Date$
*
* Implements a static class that manages user's interaction with user database.
}
unit UUserDBMgr;
interface
uses
// Project
DB.UCategory, UBaseObjects, UView;
type
{
TUserDBMgr:
Static class that manages user's interaction with user database.
}
TUserDBMgr = class(TNoConstructObject)
strict private
class procedure CanOpenDialogClose(Sender: TObject; var CanClose: Boolean);
{OnClose event handler for open dialog box. Checks if dialog box can
close.
@param Sender [in] Reference to dialog box.
@param CanClose [in/out] Set to True to permit dialog to close or False
to inhibit closure.
}
class procedure CanSaveDialogClose(Sender: TObject; var CanClose: Boolean);
{OnClose event handler for save dialog box. Checks if dialog box can
close.
@param Sender [in] Reference to dialog box.
@param CanClose [in/out] Set to True to permit dialog to close or False
to inhibit closure.
}
class function CreateUserCatList(
const IncludeSpecial: Boolean): TCategoryList;
{Creates a list of user defined categories.
@param IncludeSpecial [in] Flag indicating whether list should include
special, non-deletable, categories.
@return Required category list. Caller must free.
}
public
class procedure AddSnippet;
{Adds a new user defined snippet to database.
}
class procedure EditSnippet(const SnippetName: string);
{Gets user to edit a named snippet using edit snippet dialog box.
@param SnippetName [in] Name of snippet to be edited. Must be user
defined.
}
/// <summary>Duplicates snippet in given view as a user defined snippet
/// with name specified by user.</summary>
class procedure DuplicateSnippet(ViewItem: IView);
class procedure DeleteSnippet(ViewItem: IView);
{Deletes a snippet from the database if possible.
@param ViewItem [in] View item containing snippet to be deleted. Must be
a user defined snippet.
}
/// <summary>Checks if given view item can be duplicated.</summary>
/// <remarks>To be duplicated view must be a snippet.</summary>
class function CanDuplicate(ViewItem: IView): Boolean;
class function CanEdit(ViewItem: IView): Boolean;
{Checks if a view item can be edited.
@param ViewItem [in] View item to check.
@return True if view item can be edited, i.e. if ViewItem is a snippet
and is user defined.
}
class procedure AddCategory;
{Adds a new category to user database.
}
class procedure DeleteACategory;
{Selects and deletes a category from database if possible.
}
class procedure RenameACategory;
{Selects and renames a category in database if possible.
}
class function CanRenameACategory: Boolean;
{Checks if it is possoble to rename any categories.
@return True if there are some user-defined categories, False if not.
}
class function CanDeleteACategory: Boolean;
{Checks if it is possoble to delete any categories.
@return True if there are some user-defined, deletable, categories,
False if not.
}
class procedure Save;
{Saves user database.
}
class function CanSave: Boolean;
{Checks if user database can be saved.
@return True if database can be saved, False if not.
}
class procedure BackupDatabase;
{Creates a backup of user database in a file specified by user.
}
class function RestoreDatabase: Boolean;
{Restores user database from a previously created backup file.
@return True if user OKs, False if not.
}
end;
implementation
uses
// Delphi
SysUtils, Dialogs, Windows {for inlining},
// Project
DB.UMain, DB.USnippet, FmAddCategoryDlg, FmDeleteCategoryDlg,
FmDuplicateSnippetDlg, FmRenameCategoryDlg, FmSnippetsEditorDlg, UConsts,
UExceptions, UIStringList, UMessageBox, UOpenDialogEx, UOpenDialogHelper,
UReservedCategories, USaveDialogEx, USnippetIDs, UUserDBBackup;
{ TUserDBMgr }
class procedure TUserDBMgr.AddCategory;
{Adds a new category to user database.
}
begin
// all work takes place in dialog box
TAddCategoryDlg.Execute(nil);
end;
class procedure TUserDBMgr.AddSnippet;
{Adds a new user defined snippet to database.
}
begin
// Display Add Snippet dialog box which performs update of database.
TSnippetsEditorDlg.AddNewSnippet(nil);
end;
class procedure TUserDBMgr.BackupDatabase;
{Creates a backup of user database in a file specified by user.
}
var
FileName: string; // name of backup file
SaveDlg: TSaveDialogEx; // save dialog box used to name backup file
UserDBBackup: TUserDBBackup; // object used to perform backup
resourcestring
// Dialog box caption
sCaption = 'Save Backup';
begin
// Get backup file name from user via standard save dialog box
SaveDlg := TSaveDialogEx.Create(nil);
try
SaveDlg.OnCanClose := CanSaveDialogClose;
SaveDlg.Title := sCaption;
SaveDlg.Options := [ofShowHelp, ofExtensionDifferent, ofPathMustExist,
ofNoTestFileCreate, ofEnableSizing];
SaveDlg.HelpKeyword := 'SaveBackupDlg';
if SaveDlg.Execute then
begin
// Perform backup
FileName := SaveDlg.FileName;
UserDBBackup := TUserDBBackup.Create(FileName);
try
UserDBBackup.Backup;
finally
UserDBBackup.Free;
end;
end;
finally
SaveDlg.Free;
end;
end;
class function TUserDBMgr.CanDeleteACategory: Boolean;
{Checks if it is possoble to delete any categories.
@return True if there are some user-defined, deletable, categories, False if
not.
}
var
CatList: TCategoryList; // list of user deletable categories
begin
CatList := CreateUserCatList(False); // builds list of deletable user cats
try
Result := CatList.Count > 0;
finally
CatList.Free;
end;
end;
class function TUserDBMgr.CanDuplicate(ViewItem: IView): Boolean;
begin
Result := Supports(ViewItem, ISnippetView);
end;
class function TUserDBMgr.CanEdit(ViewItem: IView): Boolean;
{Checks if a view item can be edited.
@param ViewItem [in] View item to check.
@return True if view item can be edited, i.e. if ViewItem is a snippet and
is user defined.
}
var
SnippetView: ISnippetView; // ViewItem as snippet view if supported
begin
Assert(Assigned(ViewItem), ClassName + '.CanEdit: ViewItem is nil');
Result := Assigned(ViewItem)
and Supports(ViewItem, ISnippetView, SnippetView)
and SnippetView.Snippet.UserDefined;
end;
class procedure TUserDBMgr.CanOpenDialogClose(Sender: TObject;
var CanClose: Boolean);
{OnClose event handler for open dialog box. Checks if dialog box can close.
@param Sender [in] Reference to dialog box.
@param CanClose [in/out] Set to True to permit dialog to close or False to
inhibit closure.
}
var
FileName: string; // name of file entered in dialog box
resourcestring
// Error message
sFileDoesNotExist = '"%s" does not exist.';
begin
CanClose := False;
FileName := FileOpenEditedFileName(Sender as TOpenDialogEx);
if not FileExists(FileName) then
begin
// Specified file doesn't exist: inhibit closure
TMessageBox.Error(
Sender as TOpenDialogEx,
Format(sFileDoesNotExist, [FileName])
);
Exit;
end;
// All OK: allow closure
CanClose := True;
end;
class function TUserDBMgr.CanRenameACategory: Boolean;
{Checks if it is possoble to rename any categories.
@return True if there are some user-defined categories, False if not.
}
var
CatList: TCategoryList; // list of user renamable categories
begin
CatList := CreateUserCatList(True); // build list of all user categories
try
Result := CatList.Count > 0;
finally
CatList.Free;
end;
end;
class function TUserDBMgr.CanSave: Boolean;
{Checks if user database can be saved.
@return True if database can be saved, False if not.
}
begin
// We can save database if it's been changed
Result := (Database as IDatabaseEdit).Updated;
end;
class procedure TUserDBMgr.CanSaveDialogClose(Sender: TObject;
var CanClose: Boolean);
{OnClose event handler for save dialog box. Checks if dialog box can close.
@param Sender [in] Reference to dialog box.
@param CanClose [in/out] Set to True to permit dialog to close or False to
inhibit closure.
}
var
FileName: string; // name of file entered in dialog box
resourcestring
// Error message
sOverwritePrompt = '"%s" already exists. OK to overwrite?';
begin
FileName := FileOpenEditedFileName(Sender as TSaveDialogEx);
if FileExists(FileName) then
// File exists: allow closure if user permits file to be overwritten
CanClose := TMessageBox.Confirm(
Sender as TSaveDialogEx,
Format(sOverwritePrompt, [FileName])
);
end;
class function TUserDBMgr.CreateUserCatList(
const IncludeSpecial: Boolean): TCategoryList;
{Creates a list of user defined categories.
@param IncludeSpecial [in] Flag indicating whether list should include
special, non-deletable, categories.
@return Required category list. Caller must free.
}
var
Cat: TCategory; // references each category in snippets database
begin
Result := TCategoryList.Create;
for Cat in Database.Categories do
if Cat.UserDefined and
(IncludeSpecial or not TReservedCategories.IsReserved(Cat)) then
Result.Add(Cat);
end;
class procedure TUserDBMgr.DeleteACategory;
{Selects and deletes a category from database if possible.
}
var
CatList: TCategoryList; // list of deletable categories
begin
CatList := CreateUserCatList(False);
try
// all work takes place in dialog box
TDeleteCategoryDlg.Execute(nil, CatList)
finally
CatList.Free;
end;
end;
class procedure TUserDBMgr.DeleteSnippet(ViewItem: IView);
{Deletes a snippet from the database if possible.
@param ViewItem [in] View item containing snippet to be deleted. Must be a
user defined snippet.
}
// ---------------------------------------------------------------------------
function SnippetNames(const IDList: ISnippetIDList): IStringList;
{Builds a list of snippet names from a snippet ID list.
@param IDList [in] List of snippet IDs.
@return List of snippet names.
}
var
ID: TSnippetID; // loops through all IDs in list
Snippet: TSnippet; // snippet corresponding to ID
begin
Result := TIStringList.Create;
for ID in IDList do
begin
Snippet := Database.Snippets.Find(ID);
Result.Add(Snippet.DisplayName);
end;
end;
// ---------------------------------------------------------------------------
var
Dependents: ISnippetIDList; // list of dependent snippet IDs
Referrers: ISnippetIDList; // list referring snippet IDs
ConfirmMsg: string; // message displayed to confirm deletion
Snippet: TSnippet; // snippet being deleted
resourcestring
// Prompts & error messages
sConfirmDelete = 'Please confirm you wish to delete %s';
sConfirmDeleteEx = 'Please confirm you wish to delete %0:s.' + EOL2
+ 'Deleting this snippet will also remove it from the cross reference list '
+ 'of the following snippets:' + EOL + ' %1:s';
sHasDependents = 'Sorry, this snippet can''t be deleted. It is required by '
+ 'the following snippets:' + EOL + ' %s';
begin
Assert(Supports(ViewItem, ISnippetView),
ClassName + '.Delete: Current view is not a snippet');
Snippet := (ViewItem as ISnippetView).Snippet;
Assert(Snippet.UserDefined,
ClassName + '.Delete: Snippet must be user defined');
// Check if snippet has dependents: don't allow deletion if so
Dependents := (Database as IDatabaseEdit).GetDependents(Snippet);
if Dependents.Count > 0 then
begin
TMessageBox.Error(
nil,
Format(
sHasDependents,
[SnippetNames(Dependents).GetText(',' + EOL + ' ', False)]
)
);
Exit;
end;
// Get permission to delete. If snippet has dependents list them in prompt
Referrers := (Database as IDatabaseEdit).GetReferrers(Snippet);
if Referrers.Count = 0 then
ConfirmMsg := Format(sConfirmDelete, [Snippet.DisplayName])
else
ConfirmMsg := Format(
sConfirmDeleteEx,
[
Snippet.DisplayName,
SnippetNames(Referrers).GetText(',' + EOL + ' ', False)
]
);
if TMessageBox.Confirm(nil, ConfirmMsg) then
(Database as IDatabaseEdit).DeleteSnippet(Snippet);
end;
class procedure TUserDBMgr.DuplicateSnippet(ViewItem: IView);
begin
Assert(CanDuplicate(ViewItem),
ClassName + '.DuplicateSnippet: ViewItem can''t be duplicated');
TDuplicateSnippetDlg.Execute(nil, (ViewItem as ISnippetView).Snippet);
end;
class procedure TUserDBMgr.EditSnippet(const SnippetName: string);
{Gets user to edit a named snippet using edit snippet dialog box.
@param SnippetName [in] Name of snippet to be edited. Must be user defined.
}
var
Snippet: TSnippet; // reference to snippet to be edited
begin
Snippet := Database.Snippets.Find(SnippetName, True);
if not Assigned(Snippet) then
raise EBug.Create(ClassName + '.EditSnippet: Snippet not in user database');
TSnippetsEditorDlg.EditSnippet(nil, Snippet);
end;
class procedure TUserDBMgr.RenameACategory;
{Selects and renames a category in database if possible.
}
var
CatList: TCategoryList; // list of user defined categories
begin
CatList := CreateUserCatList(True);
try
// all work takes place in dialog box
TRenameCategoryDlg.Execute(nil, CatList)
finally
CatList.Free;
end;
end;
class function TUserDBMgr.RestoreDatabase: Boolean;
{Restores user database from a previously created backup file.
@return True if user OKs, False if not.
}
var
FileName: string; // name of backup file
Dlg: TOpenDialogEx; // open dialog box used to select backup file
UserDBBackup: TUserDBBackup; // object used to perform restoration
resourcestring
sCaption = 'Open Backup File'; // dialog box caption
begin
// Get name of backup file from user via standard open dialog box
Dlg := TOpenDialogEx.Create(nil);
try
Dlg.OnCanClose := CanOpenDialogClose;
Dlg.Title := sCaption;
Dlg.Options := [ofShowHelp, ofPathMustExist, ofHideReadOnly,
ofEnableSizing];
Dlg.HelpKeyword := 'RestoreBackupDlg';
Result := Dlg.Execute;
if Result then
begin
// Perform restoration
FileName := Dlg.FileName;
UserDBBackup := TUserDBBackup.Create(FileName);
try
UserDBBackup.Restore;
finally
UserDBBackup.Free;
end;
end;
finally
Dlg.Free;
end;
end;
class procedure TUserDBMgr.Save;
{Saves user database.
}
begin
(Database as IDatabaseEdit).Save;
end;
end.
