BorlandTalk.com Borland discussion newsgroups   Archives   FAQ   Search   Memberlist   Usergroups   Register   Profile   Log in to check your private messages   Log in  DBX3 driver raises AV when loaded by DynaLink DBX 4          BorlandTalk.com Forum Index -> Delphi Databases (dbExpress) View previous topic :: View next topic   Author Message Martijn Tonies Guest Posted: Wed Apr 11, 2007 4:30 pm    Post subject: DBX3 driver raises AV when loaded by DynaLink DBX 4 Hi, I'm working on making our driver DBX3 compatible. So far so good, I'd say. D2006 loads the driver without problems and displays data. However, when trying to use the driver with D2007, the DBXDynalink thingy tries to load it and the driver raises an error. It happens here: function TDBXDynalinkDriverCommonLoader.Load(DriverDef: TDBXDriverDef): TDBXDriver; .... ErrorResult := FMethodTable.FDBXLoader_GetDriver(Count, Names, Values, TDBXWideStringBuilder(ErrorMessageBuilder), FDriverHandle); .... I have no idea whatsoever what's going on. I cannot debug the driver from the D2007 IDE, cause it cannot compile it (due to missing dbExpress interfaces, as those are deprecated). How are we supposed to compile DBX3 drivers with D2007?? Got any clue with regard to the driver? -- Martijn Tonies Database Workbench - tool for InterBase, Firebird, MySQL, NexusDB, Oracle & MS SQL Server Upscene Productions http://www.upscene.com My thoughts: http://blog.upscene.com/martijn/ Database development questions? Check the forum! http://www.databasedevelopmentforum.com Back to top Martijn Tonies Guest Posted: Wed Apr 11, 2007 7:13 pm    Post subject: Re: DBX3 driver raises AV when loaded by DynaLink DBX 4 Quote: I have no idea whatsoever what's going on. I cannot debug the driver from the D2007 IDE, cause it cannot compile it (due to missing dbExpress interfaces, as those are deprecated). You should be able to use the D2006 PAS or DCU files for these in D2007. Right, that worked. It fails here: ISQLDriver(Obj) := DriverInstance; Where "Obj" is defined as: function getSQLDriverFB(sVendorLib : PChar; sResourceFile : PChar; out Obj): SQLResult; stdcall; This works fine in D2006, but somehow fails inside the dynalink loader... -- Martijn Tonies Database Workbench - tool for InterBase, Firebird, MySQL, NexusDB, Oracle & MS SQL Server Upscene Productions http://www.upscene.com My thoughts: http://blog.upscene.com/martijn/ Database development questions? Check the forum! http://www.databasedevelopmentforum.com Back to top Martijn Tonies Guest Posted: Wed Apr 11, 2007 7:34 pm    Post subject: Re: DBX3 driver raises AV when loaded by DynaLink DBX 4 Quote: function getSQLDriverFB(sVendorLib : PChar; sResourceFile : PChar; out Obj): SQLResult; stdcall; Is this CodeGear's code or yours? I don't know much about dbExpress innards, but returning an interface as an untyped argument is odd to say the least. That is my function. Here's how Borland (BDS 2006 and before) defined the "get driver func": type TGetDriverFunc = function(SVendorLib, SResourceFile: PChar; out Obj): SQLResult; stdcall; So, this is what I was doing. And it worked in D6, D7 and D2006... :-/ The dbExpress interfaces don't have GUIDs, so "Supports" or "as" don't work. -- Martijn Tonies Database Workbench - tool for InterBase, Firebird, MySQL, NexusDB, Oracle & MS SQL Server Upscene Productions http://www.upscene.com My thoughts: http://blog.upscene.com/martijn/ Database development questions? Check the forum! http://www.databasedevelopmentforum.com Back to top Craig Stuntz [TeamB] Guest Posted: Wed Apr 11, 2007 7:44 pm    Post subject: Re: DBX3 driver raises AV when loaded by DynaLink DBX 4 Martijn Tonies wrote: Quote: I have no idea whatsoever what's going on. I cannot debug the driver from the D2007 IDE, cause it cannot compile it (due to missing dbExpress interfaces, as those are deprecated). You should be able to use the D2006 PAS or DCU files for these in D2007. -- Craig Stuntz [TeamB] · Vertex Systems Corp. · Columbus, OH Delphi/InterBase Weblog : http://blogs.teamb.com/craigstuntz Everything You Need to Know About InterBase Character Sets: http://blogs.teamb.com/craigstuntz/articles/403.aspx Back to top Craig Stuntz [TeamB] Guest Posted: Wed Apr 11, 2007 8:28 pm    Post subject: Re: DBX3 driver raises AV when loaded by DynaLink DBX 4 Martijn Tonies wrote: Quote: function getSQLDriverFB(sVendorLib : PChar; sResourceFile : PChar; out Obj): SQLResult; stdcall; Is this CodeGear's code or yours? I don't know much about dbExpress innards, but returning an interface as an untyped argument is odd to say the least. -- Craig Stuntz [TeamB] · Vertex Systems Corp. · Columbus, OH Delphi/InterBase Weblog : http://blogs.teamb.com/craigstuntz Everything You Need to Know About InterBase Character Sets: http://blogs.teamb.com/craigstuntz/articles/403.aspx Back to top Martijn Tonies Guest Posted: Wed Apr 11, 2007 8:30 pm    Post subject: Re: DBX3 driver raises AV when loaded by DynaLink DBX 4 Quote: So, this is what I was doing. And it worked in D6, D7 and D2006... :-/ The dbExpress interfaces don't have GUIDs, so "Supports" or "as" don't work. Right, you'd have to do the hard cast. That's not really the question, though; it's the untyped argument which I found odd. But yes you'd have to conform to the type of TGetDriverFunc. Is it this assignment: ISQLDriver(Obj) := DriverInstance; ...itself which raises the AV? If so then it may be failing in trying to dereference DriverInstance. You can test this with a dummy assignment to a typed variable: var Foo: ISQLDriver; begin [...] Foo := DriverInstance; // does it fail here? This works. Quote: ISQLDriver(Obj) := DriverInstance; // or only here? This fails with the AV (read of address 00000001A). -- Martijn Tonies Database Workbench - tool for InterBase, Firebird, MySQL, NexusDB, Oracle & MS SQL Server Upscene Productions http://www.upscene.com My thoughts: http://blog.upscene.com/martijn/ Database development questions? Check the forum! http://www.databasedevelopmentforum.com Back to top Craig Stuntz [TeamB] Guest Posted: Wed Apr 11, 2007 9:10 pm    Post subject: Re: DBX3 driver raises AV when loaded by DynaLink DBX 4 Martijn Tonies wrote: Quote: So, this is what I was doing. And it worked in D6, D7 and D2006... :-/ The dbExpress interfaces don't have GUIDs, so "Supports" or "as" don't work. Right, you'd have to do the hard cast. That's not really the question, though; it's the untyped argument which I found odd. But yes you'd have to conform to the type of TGetDriverFunc. Is it this assignment: ISQLDriver(Obj) := DriverInstance; ...itself which raises the AV? If so then it may be failing in trying to dereference DriverInstance. You can test this with a dummy assignment to a typed variable: var Foo: ISQLDriver; begin [...] Foo := DriverInstance; // does it fail here? ISQLDriver(Obj) := DriverInstance; // or only here? -Craig -- Craig Stuntz [TeamB] · Vertex Systems Corp. · Columbus, OH Delphi/InterBase Weblog : http://blogs.teamb.com/craigstuntz Everything You Need to Know About InterBase Character Sets: http://blogs.teamb.com/craigstuntz/articles/403.aspx Back to top Martijn Tonies Guest Posted: Wed Apr 11, 2007 9:18 pm    Post subject: Re: DBX3 driver raises AV when loaded by DynaLink DBX 4 Quote: ISQLDriver(Obj) := DriverInstance; // or only here? This fails with the AV (read of address 00000001A). Hmmm... I'd suggest rebuilding with debug DCUs and trace into the assignment to see if you can get any closer to the error. procedure _IntfCopy(var Dest: IInterface; const Source: IInterface); {$IFDEF PUREPASCAL} var P: Pointer; begin P := Pointer(Dest); if Source <> nil then Source._AddRef; Pointer(Dest) := Pointer(Source); if P <> nil then IInterface(P)._Release; end; {$ELSE} asm { The most common case is the single assignment of a non-nil interface to a nil interface. So we streamline that case here. After this, we give essentially equal weight to other outcomes. The semantics are: The source intf must be addrefed *before* it is assigned to the destination. The old intf must be released after the new intf is addrefed to support self assignment (I := I). Either intf can be nil. The first requirement is really to make an error case function a little better, and to improve the behaviour of multithreaded applications - if the addref throws an exception, you don't want the interface to have been assigned here, and if the assignment is made to a global and another thread references it, again you don't want the intf to be available until the reference count is bumped. } TEST EDX,EDX // is source nil? JE @@NilSource PUSH EDX // save source PUSH EAX // save dest MOV EAX,[EDX] // get source vmt PUSH EDX // source as arg CALL DWORD PTR [EAX] + VMTOFFSET IInterface._AddRef POP EAX // retrieve dest MOV ECX, [EAX] // get current value POP [EAX] // set dest in place TEST ECX, ECX // is current value nil? JNE @@ReleaseDest // no, release it It jumps to ReleaseDest (current value <> nil). RET // most common case, we return here @@ReleaseDest: MOV EAX,[ECX] // get current value vmt PUSH ECX // current value as arg CALL DWORD PTR [EAX] + VMTOFFSET IInterface._Release Here, it fails with the AV. Would this mean the "Out" parameter isn't NIL? Even if so, why should it? Isn't it "Out" only? RET -- Martijn Tonies Database Workbench - tool for InterBase, Firebird, MySQL, NexusDB, Oracle & MS SQL Server Upscene Productions http://www.upscene.com My thoughts: http://blog.upscene.com/martijn/ Database development questions? Check the forum! http://www.databasedevelopmentforum.com Back to top Martijn Tonies Guest Posted: Wed Apr 11, 2007 9:27 pm    Post subject: Re: DBX3 driver raises AV when loaded by DynaLink DBX 4 Quote: ISQLDriver(Obj) := DriverInstance; // or only here? This fails with the AV (read of address 00000001A). This seems to work: Pointer(Obj) := nil; ISQLDriver(Obj) := DriverInstance; -- Martijn Tonies Database Workbench - tool for InterBase, Firebird, MySQL, NexusDB, Oracle & MS SQL Server Upscene Productions http://www.upscene.com My thoughts: http://blog.upscene.com/martijn/ Database development questions? Check the forum! http://www.databasedevelopmentforum.com Back to top Martijn Tonies Guest Posted: Wed Apr 11, 2007 9:45 pm    Post subject: Re: DBX3 driver raises AV when loaded by DynaLink DBX 4 Quote: Would this mean the "Out" parameter isn't NIL? Even if so, why should it? Isn't it "Out" only? Yes and no. "out" is the same as "var". "out" params *should* be used as out only, but the compiler doesn't enforce it. Yes, it means the out is non-nil. Calling _Release on a non-nil and not-pointing-to-any-allocated-object-implementing-an-interface can indeed raise an AV, since _Release is virtual. Your workaround seems correct to me. So I thought. I'm a bit puzzled as why this used to work before though. All this being said, I'm now getting another weird error in the DynalinkNative when FDBXConnection_GetIsolation is being used. Off to the debugger. -- Martijn Tonies Database Workbench - tool for InterBase, Firebird, MySQL, NexusDB, Oracle & MS SQL Server Upscene Productions http://www.upscene.com My thoughts: http://blog.upscene.com/martijn/ Database development questions? Check the forum! http://www.databasedevelopmentforum.com Back to top Craig Stuntz [TeamB] Guest Posted: Wed Apr 11, 2007 10:03 pm    Post subject: Re: DBX3 driver raises AV when loaded by DynaLink DBX 4 Martijn Tonies wrote: Quote: ISQLDriver(Obj) := DriverInstance; // or only here? This fails with the AV (read of address 00000001A). Hmmm... I'd suggest rebuilding with debug DCUs and trace into the assignment to see if you can get any closer to the error. -- Craig Stuntz [TeamB] · Vertex Systems Corp. · Columbus, OH Delphi/InterBase Weblog : http://blogs.teamb.com/craigstuntz Please read and follow Borland's rules for the user of their server: http://support.borland.com/entry.jspa?externalID=293 Back to top Craig Stuntz [TeamB] Guest Posted: Wed Apr 11, 2007 10:38 pm    Post subject: Re: DBX3 driver raises AV when loaded by DynaLink DBX 4 Martijn Tonies wrote: Quote: Would this mean the "Out" parameter isn't NIL? Even if so, why should it? Isn't it "Out" only? Yes and no. "out" is the same as "var". "out" params *should* be used as out only, but the compiler doesn't enforce it. Yes, it means the out is non-nil. Calling _Release on a non-nil and not-pointing-to-any-allocated-object-implementing-an-interface can indeed raise an AV, since _Release is virtual. Your workaround seems correct to me. -- Craig Stuntz [TeamB] · Vertex Systems Corp. · Columbus, OH Delphi/InterBase Weblog : http://blogs.teamb.com/craigstuntz IB 6 versions prior to 6.0.1.6 are pre-release and may corrupt your DBs! Open Edition users, get 6.0.1.6 from http://mers.com Back to top Peter Sawatzki Guest Posted: Fri Apr 13, 2007 11:50 pm    Post subject: Re: DBX3 driver raises AV when loaded by DynaLink DBX 4 Martijn, this is a bug in dbxadapter30 because the C++ definitions of ISQLCommand30.execute, ISQLCommand30.executeImmediate and ISQLCommand30.getNextCursor define their parameters as OUT while the Pascal definition is VAR. I filed a bug report on this earlier (QC #41784) already and this should be fixed for the RTM release, it is marked as fixed for build 2620 (RTM= 2627). I'm wondering why you are still seeing this. In my own driver I circumvented the crash by explicitly assigning nil to the variable casted to a pointer. from the QC: "Original definition for ISQLCommand30.execute from BDS2006 is: function execute(var Cursor: ISQLCursor30): SQLResult; stdcall; if an old style Pascal written dbx3 driver implements/derives from ISQLCommand30, the first assignment to Cursor in the driver will crash, as dbxadapter30.dll is passing a non-nil value for Cursor (and in a sense dbxadapter is correctly doing so, it assumes Cursor is an out parameter). Of course the driver could be modified by changing the definition to "out Cursor: ISQLCursor30" or the driver writer could do a "Pointer(Cursor):= nil" as the first thing in the implementing method, but this is probably not the case for most drivers. So I suggest to modify dbxadapter30.dll to initialize all (incorrectly defined) parameters it expects to receive. I think the following calls need to be modified: before calling ISQLCommand30.execute, set Pointer(Cursor):= nil; before calling ISQLCommand30.executeImmediate, set Pointer(Cursor):= nil; before calling ISQLCommand30.getNextCursor, set Pointer(Cursor):= nil;" Peter Martijn Tonies wrote: Quote: Hi, I'm working on making our driver DBX3 compatible. So far so good, I'd say. D2006 loads the driver without problems and displays data. However, when trying to use the driver with D2007, the DBXDynalink thingy tries to load it and the driver raises an error. It happens here: function TDBXDynalinkDriverCommonLoader.Load(DriverDef: TDBXDriverDef): TDBXDriver; ... ErrorResult := FMethodTable.FDBXLoader_GetDriver(Count, Names, Values, TDBXWideStringBuilder(ErrorMessageBuilder), FDriverHandle); ... I have no idea whatsoever what's going on. I cannot debug the driver from the D2007 IDE, cause it cannot compile it (due to missing dbExpress interfaces, as those are deprecated). How are we supposed to compile DBX3 drivers with D2007?? Got any clue with regard to the driver? -- Back to top Peter Sawatzki Guest Posted: Fri Apr 13, 2007 11:55 pm    Post subject: Re: DBX3 driver raises AV when loaded by DynaLink DBX 4 Craig, the bug is in dbxadapter30 and the fact that the Pascal definions of Cursor in ISQLCommand30.execute, ISQLCommand30.executeImmediate and ISQLCommand30.getNextCursor are VAR and the C++ definions are OUT. As soon as the Pascal code assigns something to Cursor the "Cursor" is freed before the assignment. See my QC # 41784 which is marked as fixed for build 2620. Peter Craig Stuntz [TeamB] wrote: Quote: Martijn Tonies wrote: function getSQLDriverFB(sVendorLib : PChar; sResourceFile : PChar; out Obj): SQLResult; stdcall; Is this CodeGear's code or yours? I don't know much about dbExpress innards, but returning an interface as an untyped argument is odd to say the least. -- Back to top Martijn Tonies Guest Posted: Sat Apr 14, 2007 12:24 am    Post subject: Re: DBX3 driver raises AV when loaded by DynaLink DBX 4 Hello Peter, In the end, I figured this out, or at least, for ISQLDriver. I've got another problem with the adapter now, the Dynalink.DerivedOpen fails, please see my other post in the dbExpress newsgroup. -- Martijn Tonies Database Workbench - tool for InterBase, Firebird, MySQL, NexusDB, Oracle & MS SQL Server Upscene Productions http://www.upscene.com My thoughts: http://blog.upscene.com/martijn/ Database development questions? Check the forum! http://www.databasedevelopmentforum.com If you can't dazzle em with brilliance, baffle em with bullshit Quote: this is a bug in dbxadapter30 because the C++ definitions of ISQLCommand30.execute, ISQLCommand30.executeImmediate and ISQLCommand30.getNextCursor define their parameters as OUT while the Pascal definition is VAR. I filed a bug report on this earlier (QC #41784) already and this should be fixed for the RTM release, it is marked as fixed for build 2620 (RTM= 2627). I'm wondering why you are still seeing this. In my own driver I circumvented the crash by explicitly assigning nil to the variable casted to a pointer. from the QC: "Original definition for ISQLCommand30.execute from BDS2006 is: function execute(var Cursor: ISQLCursor30): SQLResult; stdcall; if an old style Pascal written dbx3 driver implements/derives from ISQLCommand30, the first assignment to Cursor in the driver will crash, as dbxadapter30.dll is passing a non-nil value for Cursor (and in a sense dbxadapter is correctly doing so, it assumes Cursor is an out parameter). Of course the driver could be modified by changing the definition to "out Cursor: ISQLCursor30" or the driver writer could do a "Pointer(Cursor):= nil" as the first thing in the implementing method, but this is probably not the case for most drivers. So I suggest to modify dbxadapter30.dll to initialize all (incorrectly defined) parameters it expects to receive. I think the following calls need to be modified: before calling ISQLCommand30.execute, set Pointer(Cursor):= nil; before calling ISQLCommand30.executeImmediate, set Pointer(Cursor):= nil; before calling ISQLCommand30.getNextCursor, set Pointer(Cursor):= nil;" Peter Martijn Tonies wrote: Hi, I'm working on making our driver DBX3 compatible. So far so good, I'd say. D2006 loads the driver without problems and displays data. However, when trying to use the driver with D2007, the DBXDynalink thingy tries to load it and the driver raises an error. It happens here: function TDBXDynalinkDriverCommonLoader.Load(DriverDef: TDBXDriverDef): TDBXDriver; ... ErrorResult := FMethodTable.FDBXLoader_GetDriver(Count, Names, Values, TDBXWideStringBuilder(ErrorMessageBuilder), FDriverHandle); ... I have no idea whatsoever what's going on. I cannot debug the driver from the D2007 IDE, cause it cannot compile it (due to missing dbExpress interfaces, as those are deprecated). How are we supposed to compile DBX3 drivers with D2007?? Got any clue with regard to the driver? -- Back to top Display posts from previous: All Posts1 Day7 Days2 Weeks1 Month3 Months6 Months1 Year Oldest FirstNewest First         BorlandTalk.com Forum Index -> Delphi Databases (dbExpress) All times are GMT Page 1 of 1   Jump to: Select a forum C++ Builder Newsgroups----------------C++ BuilderC++ Builder (ActiveX)C++ Builder (Announcements)C++ Builder (Command Line Tools)C++ Builder DatabasesC++ Builder Databases (ADO)C++ Builder Databases (Desktop)C++ Builder Databases (InterBase Express)C++ Builder Databases (Multi-Tier)C++ Builder Databases (SQL Servers)C++ Builder (Graphics)C++ Builder (IDE)C++ Builder (Internet)C++ Builder (Internet Socket)C++ Builder (Internet Web)C++ Builder (Jobs)C++ Builder (Language)C++ Builder (Language C++)C++ Builder (Compatibility with MFC)C++ Builder (Native API)C++ Builder (Non-Technical)C++ Builder (Students)C++ Builder (Third Party Tools)C++ Builder (Upgrade)C++ Builder (VCL)C++ Builder (VCL Components Usage)C++ Builder (VCL Components Development)C++ Builder (VCL Usage)C++ Builder (WinAPI)C++ Builder Installation Delphi Newsgroups----------------Delphi (General)Delphi ActiveX Controls UsageDelphi ActiveX Controls DevelopmentDelphi As400Delphi DatabasesDelphi Databases (ADO)Delphi Databases (dbExpress)Delphi Databases (Desktop)Delphi Databases (InterBase Express)Delphi Databases (Multi-Tier)Delphi Databases (SQL Servers)Delphi DeploymentDelphi GraphicsDelphi IDEDelphi InternationalizationDelphi InternetDelphi Internet Isapi-WebBrokerDelphi Internet WebSnapDelphi Internet WinsockDelphi JobsDelphi Language BASMDelphi Language ObjectPascalDelphi Model Driven Architecture (General)Delphi Model Driven Architecture (Third Party)Delphi MultimediaDelphi Native APIDelphi Non-TechnicalDelphi ObjectPascalDelphi OLE AutomationDelphi OO designDelphi OpenToolsAPIDelphi Reporting-ChartingDelphi RTLDelphi StudentsDelphi TeamSourceDelphi Thirdparty ToolsDelphi Thirdparty Tools (General)Delphi Thirdparty Tools (IntraWeb)Delphi Thirdparty Tools (RaveReports)Delphi UpgradeDelphi VCLDelphi VCL ComponentsDelphi VCL Components UsingDelphi VCL Components WritingDelphi WebServices SOAPDelphi WinAPIDelphi XMLDelphi Installationcomp.lang.pascal.delphi.components.misccomp.lang.pascal.delphi.components.usagecomp.lang.pascal.delphi.components.writingcomp.lang.pascal.delphi.databasescomp.lang.pascal.delphi.misccomp.sources.delphi JBuilder Newsgroups----------------JBuilderJBuilder AnnouncementsJBuilder Applet IssuesJBuilder As400JBuilder CompilerJBuilder CORBA/RMIJBuilder DatabasesJBuilder DB SwingJBuilder DebuggerJBuilder DeploymentJBuilder DocumentationJBuilder EnterpriseJBuilder HandheldJBuilder IDEJBuilder JavaJBuilder JavaAPIJBuilder Java LanguageJBuilder Java SwingJBuilder Java BeansJBuilder Java Beans UsageJBuilder Java Beans DevelopmentJBuilder JBCLJBuilder JDataStoreJBuilder JobsJBuilder LinuxJBuilder MacintoshJBuilder & MobileSetJBuilder MultiLingual AppsJBuilder Non-TechnicalJBuilder OpenToolsJBuilder Servlets (JSP)JBuilder StudentsJBuilder Team DevelopmentJBuilder Thirdparty ToolsJBuilder UpgradeJBuilder Installation InterBase Newsgroups----------------InterBaseInterBase Bug DiscussionInterBase GeneralInterBase IBConsoleInterBase OpenSourceInterBase ReplicationInterBase SQLInterBase ThirdpartyInterBase Installation Miscellaneous Borland Newsgroups----------------AppCenterAppServerEnteraVisiBroker  You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot vote in polls in this forum Powered by phpBB © 2001, 2006 phpBB Group SEO toolkit © 2004-2006 webmedic.