ChmHelp: Improve LHelp and related packages. Issue #24743, patch from Reinier Olislagers

git-svn-id: trunk@42270 -

components/chmhelp/lhelp/chmcontentprovider.pas

@@ -5,9 +5,6 @@ unit chmcontentprovider;
 {$Note Compiling lhelp with search support}
 {$DEFINE CHM_SEARCH}
 
-//{$else}
-//{$Note Compiling lhelp *without* search support since your fpc version is not new enough}
-//{$endif}
 {$if (fpc_version=2) and (fpc_release>4)}
 {$Note Compiling lhelp *with* binary index and toc support}
 {$DEFINE CHM_BINARY_INDEX_TOC}
@@ -15,7 +12,7 @@ unit chmcontentprovider;
 
 
 {off $DEFINE CHM_DEBUG_TIME}
-{off $DEFINE CHM_SEARCH}
+
 
 interface
 
@@ -540,11 +537,9 @@ begin
   fStatusBar.SimpleText:= '';
 
   {$IFDEF CHM_DEBUG_TIME}
-  writeln('Eind: ',FormatDateTime('hh:nn:ss.zzz', Now));
+  writeln('End: ',FormatDateTime('hh:nn:ss.zzz', Now));
   {$ENDIF}
 
-
-
   {$IFDEF CHM_SEARCH}
   i := 0;
   while (HasSearchIndex = False) and (i < fChms.Count) do

components/chmhelp/lhelp/lhelp.lpi

@@ -1,4 +1,4 @@
-<?xml version="1.0"?>
+<?xml version="1.0" encoding="UTF-8"?>
 <CONFIG>
   <ProjectOptions>
     <Version Value="9"/>

components/chmhelp/lhelp/lhelp.lpr

@@ -1,5 +1,7 @@
 { Copyright (C) <2005> <Andrew Haines> lhelp.lpr
 
+  Lhelp CHM help viewer application
+
   This source is free software; you can redistribute it and/or modify it under
   the terms of the GNU General Public License as published by the Free
   Software Foundation; either version 2 of the License, or (at your option)
@@ -21,12 +23,8 @@ program lhelp;
 
 uses
   Interfaces, // this includes the LCL widgetset
-  SysUtils,
+  SysUtils, Classes, Controls, Dialogs, Forms,
-  Classes,
+  SimpleIPC, TurboPowerIPro, chmpopup, lhelpcontrolpkg, lhelpcore;
-  Controls,
-  Dialogs,
-  Forms
-  { add your units here }, SimpleIPC, TurboPowerIPro, chmpopup, lhelpcontrolpkg, lhelpcore;
 
 var
  X: Integer;
@@ -40,14 +38,15 @@ begin
     if LowerCase(ParamStr(X)) = '--help' then 
     begin
       S := TStringList.Create;
-      S.Add('  LHelp Options:');
+      S.Add('  LHelp options:');
       S.Add('');
-      S.Add('    Usage: lhelp [[filename] [--context id] [--ipcname lhelp-myapp]]');
+      S.Add('    Usage: lhelp [[filename] [--context id] [--hide] [--ipcname lhelp-myapp]]');
       S.Add('');
       S.Add('    --help     :  Show this information');
+      S.Add('    --hide     :  Start hidden but accept communications via IPC');
       S.Add('    --context  :  Show the help information related');
       S.Add('                  to this context');
-      S.Add('    --ipcname  :  The name of the ipc server to listen on for');
+      S.Add('    --ipcname  :  The name of the IPC server to listen on for');
       S.Add('                  programs who wish to control the viewer');
 
       if TextRec(Output).Mode = fmClosed then
@@ -60,15 +59,22 @@ begin
     end;
   Application.CreateForm(THelpForm, HelpForm);
   Application.CreateForm(THelpPopupForm, HelpPopupForm);
+
   try
   Application.Run;
   except
-    // try to remove stale names pipes so that a new instance can use them
+    // try to remove stale named pipes so that a new instance can use them
     if IPCServer <> nil then
     try
     FreeAndNil(IPCServer);
     except
     end;
+
+    if IPCClient <> nil then
+    try
+    FreeAndNil(IPCClient);
+    except
+    end;
   end;
 end.
 

components/chmhelp/lhelp/lhelpcore.lfm

@@ -5,7 +5,7 @@ object HelpForm: THelpForm
   Width = 758
   ActiveControl = Panel1
   Caption = 'LHelp'
-  ClientHeight = 515
+  ClientHeight = 516
   ClientWidth = 758
   Icon.Data = {
     7E04000000000100010010100000010020006804000016000000280000001000
@@ -52,7 +52,7 @@ object HelpForm: THelpForm
   OnKeyUp = FormKeyUp
   OnShow = FormShow
   Position = poScreenCenter
-  LCLVersion = '0.9.31'
+  LCLVersion = '1.1'
   Visible = True
   object Panel1: TPanel
     Left = 0
@@ -105,7 +105,6 @@ object HelpForm: THelpForm
         8B000000000000000000B07522006780280037221A005E392A00683B2C009129
         1B000000000038AB3E000000000068BC74000000000000000000
       }
-      NumGlyphs = 0
       OnClick = ForwardToolBtnClick
     end
     object BackBttn: TSpeedButton
@@ -150,7 +149,6 @@ object HelpForm: THelpForm
         8B00000000000000000053575500535755005659580000000000000000000000
         0000000000000000000000000000000000000000000000000000
       }
-      NumGlyphs = 0
       OnClick = BackToolBtnClick
     end
     object HomeBttn: TSpeedButton
@@ -235,13 +233,12 @@ object HelpForm: THelpForm
         EA00E4E7EA00E4E7EA00E4E7EA00E4E7EA00E4E7EA00E4E7EA00E4E7EA00E4E7
         EA00E4E7EA00E4E7EA00E4E7EA00E4E7EA00E4E7EA00E4E7EA00
       }
-      NumGlyphs = 0
       OnClick = HomeToolBtnClick
     end
   end
   object PageControl: TPageControl
     Left = 0
-    Height = 483
+    Height = 484
     Top = 32
     Width = 758
     Align = alClient

components/chmhelp/lhelp/lhelpcore.pas

@@ -1,4 +1,6 @@
-{ Copyright (C) 2005  Andrew Haines
+{ Copyright (C) 2005-2013  Andrew Haines, Lazarus contributors
+
+  Main form for lhelp. Includes processing/data communication.
 
   This source is free software; you can redistribute it and/or modify it under
   the terms of the GNU General Public License as published by the Free
@@ -95,27 +97,46 @@ type
   private
     { private declarations }
     fServerName: String;
+    // Receives commands from IDE
     fInputIPC: TSimpleIPCServer;
+    // Sends responses back to IDE
+    // only used if lhelp started with --ipcname to indicate
+    // IPC communication method should be used
     fOutputIPC: TSimpleIPCClient;
     fServerTimer: TTimer;
     fContext: LongInt; // used once when we are started on the command line with --context
     fConfig: TXMLConfig;
     FHasShowed: Boolean;
+    fHide: boolean; //If yes, start with content hidden. Otherwise start normally
+    // Load preferences; separate preferences per coupled server/IDE
     procedure LoadPreferences(AIPCName: String);
-    procedure SavePreferences({%H-}AIPCName: String);
+    // Saves preferences. Uses existing config loaded by LoadPreferences
+    procedure SavePreferences;
     procedure AddRecentFile(AFileName: String);
     procedure ContentTitleChange({%H-}sender: TObject);
     procedure OpenRecentItemClick(Sender: TObject);
+    // Send response back to server (IDE)
+    // Used to acknowledge commands from the server
     procedure SendResponse(Response: DWord);
+    // Wait for message from server (IDE) and process
     procedure ServerMessage(Sender: TObject);
+    // Parse any given command line options
     procedure ReadCommandLineOptions;
-    procedure StartServer(ServerName: String);
+    // Start simple IPC server/client
-    procedure StopServer;
+    // ServerName can be the variable passed to --ipcname
-    function  OpenURL(const AURL: String; AContext: THelpContext=-1): DWord;
+    // It is used both for starting up the local server and to ID the remote server
+    procedure StartComms(ServerName: String);
+    // Stop simple IPC server/client
+    procedure StopComms;
+    // Open specified URL in viewer window
+    function OpenURL(const AURL: String; AContext: THelpContext=-1): DWord;
+    // Open specified URL - presumably used to queue URLs for delayed opening
     procedure LateOpenURL(Url: PStringItem);
     function ActivePage: TContentTab;
+    // Update UI visibility
     procedure RefreshState;
     procedure ShowError(AError: String);
+    // Set keyup handler for control (and any child controls)
     procedure SetKeyUp(AControl: TControl);
   public
     { public declarations }
@@ -124,8 +145,12 @@ type
 
 var
   HelpForm: THelpForm;
+  IPCClient: TSimpleIPCClient;
   IPCServer: TSimpleIPCServer;
-const INVALID_FILE_TYPE = 1;
+
+const
+  INVALID_FILE_TYPE = 1;
+  VERSION_STAMP = '2013-07-31'; //used in displaying about form etc
 
 implementation
 
@@ -160,14 +185,15 @@ begin
     f.BorderStyle := bsDialog;
     f.Position := poMainFormCenter;
     f.Constraints.MinWidth := 150;
-    f.Constraints.MaxWidth := 250;
+    f.Constraints.MaxWidth := 350;
     l := TLabel.Create(f);
     l.Parent := f;;
     l.Align := alTop;
     l.BorderSpacing.Around := 6;
     l.Caption := 'LHelp (CHM file viewer)' + LineEnding +
-      'Ver. 2009.06.08' + LineEnding +
+      'Version ' + VERSION_STAMP + LineEnding +
-      'Copyright (C) Andrew Haines';
+      'Copyright (C) Andrew Haines, ' + LineEnding +
+      'Lazarus contributors';
     l.AutoSize := True;
     l.WordWrap := True;
     b := TButton.Create(f);
@@ -236,7 +262,7 @@ begin
   URLSAllowed := Trim(URLSALLowed);
 
   fRes:='';
-  if InputQuery('Please Enter a URL', 'Supported URL type(s): (' +URLSAllowed+ ')', fRes) then
+  if InputQuery('Please enter a URL', 'Supported URL type(s): (' +URLSAllowed+ ')', fRes) then
   begin
     if OpenURL(fRes) = ord(srSuccess) then
       AddRecentFile(fRes);
@@ -249,17 +275,19 @@ begin
   Visible:= False;
   Application.ProcessMessages;
   FileMenuCloseItemClick(Sender);
-  StopServer;
+  StopComms;
-  SavePreferences(fServerName);
+  SavePreferences;
 end;
 
 procedure THelpForm.FormCreate(Sender: TObject);
 begin
   fContext := -1;
+  fHide := false;
   ReadCommandLineOptions;
   LoadPreferences(fServerName);
+  // Only start IPC if server name passed in --ipcname
   if fServerName <> '' then begin
-    StartServer(fServerName);
+    StartComms(fServerName);
   end;
   RefreshState;
   SetKeyUp(Self);
@@ -279,7 +307,6 @@ begin
   if FHasShowed then
     Exit;
   FHasShowed := True;
-
 end;
 
 procedure THelpForm.ForwardToolBtnClick(Sender: TObject);
@@ -319,11 +346,16 @@ procedure THelpForm.LoadPreferences(AIPCName: String);
 var
   PrefFile: String;
   RecentCount: Integer;
+  ServerPart: String;
   i: Integer;
 begin
   PrefFile := GetAppConfigDirUTF8(False);
   ForceDirectoriesUTF8(PrefFile);
-  PrefFile:=Format('%slhelp-%s.conf',[IncludeTrailingPathDelimiter(PrefFile), AIPCName]);
+  // --ipcname passes a server ID that consists of a
+  // a server-dependent constant together with a process ID.
+  // Strip out the process ID to get fixed config file names for one server
+  ServerPart := Copy(AIPCName, 1, length(AIPCName)-5); //strip out PID
+  PrefFile:=Format('%slhelp-%s.conf',[IncludeTrailingPathDelimiter(PrefFile), ServerPart]);
 
   fConfig := TXMLConfig.Create(Self);
   fConfig.Filename:=PrefFile;
@@ -333,6 +365,9 @@ begin
   Width  := fConfig.GetValue('Position/Width/Value',  Width);
   Height := fConfig.GetValue('Position/Height/Value', Height);
 
+  if fConfig.GetValue('Position/Maximized',false)=true then
+    Windowstate:=wsMaximized;
+
   OpenDialog1.FileName := fConfig.GetValue('LastFileOpen/Value', OpenDialog1.FileName);
 
   RecentCount:= fConfig.GetValue('Recent/ItemCount/Value', 0);
@@ -341,7 +376,7 @@ begin
     AddRecentFile(fConfig.GetValue('Recent/Item'+IntToStr(i)+'/Value',''));
 end;
 
-procedure THelpForm.SavePreferences(AIPCName: String);
+procedure THelpForm.SavePreferences;
 var
   i: Integer;
 begin
@@ -351,6 +386,10 @@ begin
     fConfig.SetValue('Position/Top/Value',    Top);
     fConfig.SetValue('Position/Width/Value',  Width);
     fConfig.SetValue('Position/Height/Value', Height);
+  end
+  else
+  begin
+    fConfig.SetValue('Position/Maximized', true);
   end;
 
   fConfig.SetValue('LastFileOpen/Value', OpenDialog1.FileName);
@@ -412,31 +451,27 @@ procedure THelpForm.SendResponse(Response: DWord);
 var
   Stream: TMemoryStream;
 begin
-  fOutputIPC := TSimpleIPCClient.Create(nil);
-  fOutputIPC.ServerID := fServerName+'client';
-  if fOutputIPC.ServerRunning {$IFDEF STALE_PIPE_WORKAROUND} and not IPCPipeIsStale(fOutputIPC){$ENDIF}
-  then
-    fOutputIPC.Active := True;
-
   Stream := TMemoryStream.Create;
-  Stream.WriteDWord(Response);
+  try
+    Stream.WriteDWord(Response);
 
-  if fOutputIPC.Active then
+    if assigned(fOutputIPC) and fOutputIPC.Active then
-    fOutputIPC.SendMessage(mtUnknown, Stream);
+      fOutputIPC.SendMessage(mtUnknown, Stream);
-
+  finally
-  if fOutputIPC.Active then
+    Stream.Free;
-    fOutputIPC.Active := False;
+  end;
-  FreeAndNil(fOutputIPC);
 end;
 
 procedure THelpForm.ServerMessage(Sender: TObject);
 var
   UrlReq: TUrlRequest;
-  FileReq:TFileRequest;
+  FileReq: TFileRequest;
   ConReq: TContextRequest;
+  MiscReq: TMiscRequest;
+  MustClose: boolean=false;
   Stream: TStream;
   Res: LongWord;
-  Url: String;
+  Url: String='';
 begin
   if fInputIPC.PeekMessage(5, True) then begin
     Stream := fInputIPC.MsgData;
@@ -470,13 +505,48 @@ begin
                     Url := 'file://'+FileReq.FileName;
                     Res := OpenURL(Url, ConReq.HelpContext);
                   end;
+      rtMisc    : begin
+                    Stream.Position := 0;
+                    FillByte(MiscReq{%H-},SizeOf(MiscReq),0);
+                    Stream.Read(MiscReq, SizeOf(MiscReq));
+                    case MiscReq.RequestID of
+                      mrClose:
+                      begin
+                        MustClose:=true;
+                        Res:= ord(srSuccess);
+                      end;
+                      mrShow:
+                      begin
+                        fHide := false;
+                        PageControl.Visible:=true;
+                        Res := ord(srSuccess);
+                      end;
+                      mrVersion:
+                      begin
+                        //Protocol version encoded in the filename
+                        // Verify what we support
+                        if strtointdef(FileReq.FileName,0)=strtointdef(PROTOCOL_VERSION,0) then
+                          Res := ord(srSuccess)
+                        else
+                          Res := ord(srError); //version not supported
+                      end
+                      else {Unknown}
+                        Res := ord(srUnknown);
+                    end;
+                  end;
     end;
-    if Res = Ord(srSuccess) then
+    if (URL<>'') and (Res = Ord(srSuccess)) then
       AddRecentFile(Url);
     SendResponse(Res);
-    Self.SendToBack;
+    if MustClose then
-    Self.BringToFront;
+      Application.Terminate;
-    Self.ShowOnTop;
+
+    if (MustClose=false) and (fHide=false) then
+    begin
+      Self.SendToBack;
+      Self.BringToFront;
+      Self.ShowOnTop;
+    end;
   end;
 end;
 
@@ -499,7 +569,7 @@ begin
         IsHandled[X] := True;
         inc(X);
       end;
-    end else  if LowerCase(ParamStrUTF8(X)) = '--context' then begin
+    end else if LowerCase(ParamStrUTF8(X)) = '--context' then begin
       IsHandled[X] := True;
       inc(X);
       if (X <= ParamCount) then
@@ -507,11 +577,16 @@ begin
           IsHandled[X] := True;
           inc(X);
         end;
+    end else if LowerCase(ParamStrUTF8(X)) = '--hide' then begin
+      IsHandled[X] := True;
+      inc(X);
+      fHide:=true;
     end else begin
       IsHandled[X]:=copy(ParamStrUTF8(X),1,1)='-'; // ignore other parameters
       inc(X);
     end;
   end;
+
   // Loop through a second time for the url
   for X := 1 to ParamCount do
     if not IsHandled[X] then begin
@@ -535,9 +610,13 @@ begin
     end;
 end;
 
-procedure THelpForm.StartServer(ServerName: String);
+procedure THelpForm.StartComms(ServerName: String);
-begin
+// Starts IPC server and client for two-way communication with
+// controlling program (e.g. Lazarus IDE).
 
+// Only useful if IPC serverID is passed through the --ipcname
+// command.
+begin
   fInputIPC := TSimpleIPCServer.Create(nil);
   fInputIPC.ServerID := ServerName;
   fInputIPC.Global := True;
@@ -550,20 +629,38 @@ begin
   fServerTimer.Enabled := True;
   ServerMessage(nil);
 
-
+  fOutputIPC := TSimpleIPCClient.Create(nil);
+  fOutputIPC.ServerID := ServerName+'client';
+  try
+    if fOutputIPC.ServerRunning {$IFDEF STALE_PIPE_WORKAROUND} and not IPCPipeIsStale(fOutputIPC){$ENDIF}
+    then
+      fOutputIPC.Active := True;
+  except
+    fOutputIPC.Active := False;
+  end;
+  IPCClient := fOutputIPC;
 end;
 
-procedure THelpForm.StopServer;
+procedure THelpForm.StopComms;
 begin
-   if fInputIPC = nil then
+   if fInputIPC <> nil then
-     exit;
+   begin
+     if fInputIPC.Active then
+       fInputIPC.Active := False;
 
-   if fInputIPC.Active then
+     FreeAndNil(fInputIPC);
-     fInputIPC.Active := False;
+     IPCServer := nil;
+     FreeAndNil(fServerTimer);
+   end;
 
-   FreeAndNil(fInputIPC);
+   if fOutputIPC <> nil then
-   IPCServer := nil;
+   begin
-   FreeAndNil(fServerTimer);
+     if fOutputIPC.Active then
+       fOutputIPC.Active := False;
+
+     FreeAndNil(fOutputIPC);
+     IPCClient := nil;
+   end;
 end;
 
 function THelpForm.OpenURL(const AURL: String; AContext: THelpContext): DWord;
@@ -598,7 +695,6 @@ begin
    Exit;
  end;
 
- 
  for I := 0 to PageControl.PageCount-1 do begin
    if fRealContentProvider.ClassName = TContentTab(PageControl.Pages[I]).ContentProvider.ClassName then begin
      fPage := TContentTab(PageControl.Pages[I]);
@@ -615,7 +711,7 @@ begin
 
  if fPage = nil then
  begin
-   //no page was found already to handle this content so create one
+   //no existing page that can handle this content, so create one
    fPage := TContentTab.Create(PageControl);
    fPage.ContentProvider := fRealContentProvider.Create(fPage, ImageList1);
    fPAge.ContentProvider.OnTitleChange:=@ContentTitleChange;
@@ -634,7 +730,8 @@ begin
  else
    Result := Ord(srInvalidFile);
 
- ShowOnTop;
+ if not fHide then
+   ShowOnTop;
 end;
 
 
@@ -659,7 +756,25 @@ procedure THelpForm.RefreshState;
 var
   en: Boolean;
 begin
-  en := Assigned(ActivePage);
+  if fHide then
+  begin
+    en := false;
+    // Hide content page
+    // todo: even though this code perhaps will hide the content window,
+    // starting laz+pressing f1 will show content while loading all chms
+    if Assigned(ActivePage) then
+      with TChmContentProvider(ActivePage.ContentProvider) do
+      begin
+        ActivePage.Visible:=false;
+        Visible:=false;
+        //todo: are these necessary
+        TabsControl.Visible := false;
+        Splitter.Visible := false;
+      end;
+  end
+  else
+    en := Assigned(ActivePage);
+
   BackBttn.Enabled := en;
   ForwardBttn.Enabled := en;
   HomeBttn.Enabled := en;
@@ -685,7 +800,7 @@ begin
   if (AControl = nil) or not (AControl.InheritsFrom(TWinControl)) then
     Exit;
   for i := 0 to WCont.ControlCount-1 do
-      SetKeyUp(WCont.Controls[i]);
+    SetKeyUp(WCont.Controls[i]);
   WCont.OnKeyUp:=@FormKeyUp;
 end;
 
@@ -705,6 +820,7 @@ end;
 finalization
   if IPCServer <> nil then
     FreeAndNil(IPCServer);
-
+  if IPCClient <> nil then
+    FreeAndNil(IPCClient);
 end.
 

components/chmhelp/packages/help/lazhelpchm.pas

@@ -7,7 +7,7 @@
   Author: Mattias Gaertner
 
   Abstract:
-    Methods and types for simple CHM help using chm viewer "lhelp".
+    Methods and types for CHM help using chm viewer "lhelp".
 }
 unit LazHelpCHM;
 

components/chmhelp/packages/help/lhelpcontrol.pas

@@ -4,8 +4,7 @@ unit LHelpControl;
 Starts, stops and controls external help viewer via IPC.
 This is used to display context-sensitive help in Lazarus, and could be used in applications to do the same.
 
-This unit serves as reference implementation and documentation of the protocol used to communicate with help viewers.
+Also contains definitions used by both Lazarus IDE and help viewers.
-
 Currently, the only help viewer that supports this protocol is the lhelp CHM help viewer.
 }
 
@@ -25,12 +24,16 @@ uses
   {$ENDIF}
   Classes, SysUtils, FileUtil, LazLogger, SimpleIPC, process, UTF8Process;
 
+const
+  PROTOCOL_VERSION='1'; //IDE<>LHelp communication protocol version. Please update when breaking compatibility
 type
-  TRequestType = (rtFile, rtUrl, rtContext);
+  TRequestType = (rtFile, rtUrl, rtContext, rtMisc {window handling etc});
+  TMiscRequests = (mrShow, mrVersion, mrClose);
 
-  TLHelpResponse = (srNoAnswer, srUnknown, srSuccess, srInvalidFile, srInvalidURL, srInvalidContext);
+  TLHelpResponse = (srError, srNoAnswer, srUnknown, srSuccess, srInvalidFile, srInvalidURL, srInvalidContext);
 
   TFileRequest = record
+    // Opening files
     RequestType: TRequestType;
     FileName: array[0..512] of char;
   end;
@@ -42,6 +45,11 @@ type
     FileRequest: TFileRequest;
     HelpContext: THelpContext;
   end;
+  TMiscRequest = record
+    // In this record, the FileName array may have a meaning specific to the request ID.
+    FileRequest: TFileRequest;
+    RequestID: TMiscRequests;
+  end;
 
   TProcedureOfObject = procedure of object;
   
@@ -52,22 +60,26 @@ type
     FProcessWhileWaiting: TProcedureOfObject;
     fServerOut: TSimpleIPCClient; // sends messages to lhelp
     fServerIn:  TSimpleIPCServer; // recieves messages from lhelp
+    // Wait for help viewer to respond in a reasonable timeframe and return the response
     function  WaitForMsgResponse: TLHelpResponse;
+    // Send a message to the help viewer
     function  SendMessage(Stream: TStream): TLHelpResponse;
   public
     constructor Create;
     destructor Destroy; override;
     // Checks whether the server is running using SimpleIPC
     function ServerRunning: Boolean;
-    // Starts server
+    // Starts remote server (help viewer); if Hide specified, asks the help server to hide itself/run minimized while starting
     // Server must support a switch --ipcname that accepts the NameForServer argument to identify it for SimpleIPC
-    function StartHelpServer(NameForServer: String; ServerEXE: String = ''): Boolean;
+    function StartHelpServer(NameForServer: String; ServerEXE: String = '';Hide: boolean=false): Boolean;
     // Shows URL in the HelpFileName file by sending a TUrlRequest
     function OpenURL(HelpFileName: String; Url: String): TLHelpResponse;
     // Shows help for Context in the HelpFileName file by sending a TContextRequest request
     function OpenContext(HelpFileName: String; Context: THelpContext): TLHelpResponse;
     // Opens HelpFileName by sending a TContextRequest
     function OpenFile(HelpFileName: String): TLHelpResponse;
+    // Requests to run command on viewer by sending a TMiscrequest
+    function RunMiscCommand(CommandID: TMiscRequests): TLHelpResponse;
     property ProcessWhileWaiting: TProcedureOfObject read FProcessWhileWaiting write FProcessWhileWaiting;
   end;
 
@@ -169,7 +181,7 @@ begin
 end;
 
 function TLHelpConnection.StartHelpServer(NameForServer: String;
-  ServerEXE: String): Boolean;
+  ServerEXE: String; Hide: boolean=false): Boolean;
 var
   X: Integer;
   Cmd: String;
@@ -184,7 +196,8 @@ begin
   fServerOut.Active := False;
   fServerOut.ServerID := NameForServer;
   if not ServerRunning then begin
-    Cmd:= ServerExe + ' --ipcname ' + NameForServer;
+    Cmd := ServerExe + ' --ipcname ' + NameForServer;
+    if Hide then Cmd := Cmd + ' --hide';
     {$IFDEF darwin}
     if DirectoryExistsUTF8(ServerEXE+'.app') then
       ServerEXE+='.app';
@@ -265,5 +278,29 @@ begin
   end;
 end;
 
+function TLHelpConnection.RunMiscCommand(CommandID: TMiscRequests): TLHelpResponse;
+var
+  MiscRequest : TMiscRequest;
+  Stream: TMemoryStream;
+begin
+  Stream := TMemoryStream.Create;
+  try
+    MiscRequest.FileRequest.RequestType := rtMisc;
+    MiscRequest.FileRequest.FileName := ''+#0; //i
+    //CommandID is ord(TMiscRequests)
+    MiscRequest.RequestID:=CommandID;
+    case CommandID of
+      mrClose: ; //do nothing
+      mrShow: ;  //do nothing
+      mrVersion:
+        MiscRequest.FileRequest.FileName := PROTOCOL_VERSION+#0;
+    end;
+    Stream.Write(MiscRequest, SizeOf(MiscRequest));
+    Result := SendMessage(Stream);
+  finally
+    Stream.Free;
+  end;
+end;
+
 end.
 

components/chmhelp/packages/idehelp/lazchmhelp.pas

@@ -1,4 +1,8 @@
-{ Copyright (C) <2005> <Andrew Haines> lazchmhelp.pas
+{ Copyright (C) <2005-2013> <Andrew Haines>, Lazarus contributors
+
+  lazchmhelp.pas
+
+  Lazarus IDE support for lhelp/chm help files. Can start and control lhelp application.
 
   This source is free software; you can redistribute it and/or modify it under
   the terms of the GNU General Public License as published by the Free
@@ -41,7 +45,7 @@ type
   TChmHelpViewer = class(THelpViewer)
   private
     fHelpExe: String;
-    fHelpLabel: String;
+    fHelpLabel: String; //ID used for SimpleIPC identification
     fHelpConnection: TLHelpConnection;
     fCHMSearchPath: String;
     fHelpExeParams: String;
@@ -77,6 +81,7 @@ type
     function GetHelpFilesPath: String; // macros resolved, see property HelpFilesPath
   published
     property HelpEXE: String read fHelpEXE write SetHelpEXE; // with macros, see GetHelpEXE
+    // ID used for SimpleIPC communication with the help viewer
     property HelpLabel: String read GetHelpLabel write SetHelpLabel;
     property HelpFilesPath: String read fCHMSearchPath write SetChmsFilePath; // directories separated with semicolon, with macros, see GetHelpFilesPath
     property HelpExeParams: String read fHelpExeParams write fHelpExeParams;
@@ -115,8 +120,12 @@ end;
 
 function TChmHelpViewer.GetHelpLabel: String;
 begin
+  // fHelpLable is used for SimpleIPC server id;
+  // lhelp protocol specifies server-dependent constant string
+  // followed by string representation of last 5 digits of the processID
+  // padded with 00000 at the right
   if Length(fHelpLabel) = 0 then
-    fHelpLabel := 'lazhelp';
+    fHelpLabel := 'lazhelp'+copy(inttostr(GetProcessID)+'00000',1,5);
   Result := fHelpLabel;
 end;
 
@@ -418,6 +427,7 @@ end;
 
 procedure TChmHelpViewer.ShowAllHelp(Sender: TObject);
 var
+  Response: TLHelpResponse;
   SearchPath: String; //; delimited list of directories
   HelpExeFileName: String;
 begin
@@ -434,13 +444,27 @@ begin
   end;
 
   SearchPath := GetHelpFilesPath;
-  // Start up server if needed
+  // Start up help viewer if needed - and tell it to hide
   if not(fHelpConnection.ServerRunning) then
   begin
-    fHelpConnection.StartHelpServer(HelpLabel, HelpExeFileName);
+    fHelpConnection.StartHelpServer(HelpLabel, HelpExeFileName, true);
+    Response:=fHelpConnection.RunMiscCommand(mrVersion);
+    if Response<>srSuccess then
+    begin
+      debugln('Help viewer does not support our protocol version.');
+    end
+    else
+    begin
+      // Open all chm files after it has started, while still hidden
+      OpenAllCHMsInSearchPath(SearchPath);
+      // Instruct viewer to show its GUI
+      Response:=fHelpConnection.RunMiscCommand(mrShow);
+      if Response<>srSuccess then
+      begin
+        debugln('Help viewer failed to respond to mrShow command.');
+      end;
+    end;
   end;
-  // Open all chm files after it has started
-  OpenAllCHMsInSearchPath(SearchPath);
 end;
 
 function TChmHelpViewer.ShowNode(Node: THelpNode; var ErrMsg: string
@@ -569,7 +593,7 @@ procedure TChmHelpViewer.Load(Storage: TConfigStorage);
 begin
   HelpEXE:=Storage.GetValue('CHMHelp/Exe','');
   HelpExeParams := Storage.GetValue('CHMHelp/ExeParams','');
-  HelpLabel:=Storage.GetValue('CHMHelp/Name','lazhelp');
+  HelpLabel:=Storage.GetValue('CHMHelp/Name','lazhelp')+inttostr(GetProcessID);
   HelpFilesPath := Storage.GetValue('CHMHelp/FilesPath','');
 end;