issue about Memory VFS already contains file xxx when re-enable a plugin

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issue about Memory VFS already contains file xxx when re-enable a plugin

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ollydbg:
When I debug the code we discussed in Re: Allowing Plugin Interdependency and Improving Plugin Management, I notice an error message box from wx, here is the call stack:

--- Code: ---[debug]> bt 30
[debug]#0 wxMemoryFSHandlerBase::CheckDoesntExist (filename=L"codecompletion.zip") at F:\wx\wxWidgets_trunk\src\common\fs_mem.cpp:175
[debug]#1 0x01970787 in wxMemoryFSHandlerBase::AddFileWithMimeType (filename=L"codecompletion.zip", binarydata=0x11671dc0, size=7580, mimetype=L"") at F:\wx\wxWidgets_trunk\src\common\fs_mem.cpp:199
[debug]#2 0x01970889 in wxMemoryFSHandlerBase::AddFile (filename=L"codecompletion.zip", binarydata=0x11671dc0, size=7580) at F:\wx\wxWidgets_trunk\src\common\fs_mem.cpp:217
[debug]#3 0x694ec051 in wxMemoryFSHandler::AddFile (filename=L"codecompletion.zip", binarydata=0x11671dc0, size=7580) at F:\wx\wxWidgets_trunk\include\wx\fs_mem.h:97
[debug]#4 0x6933518e in Manager::LoadResource (file=L"codecompletion.zip") at F:\jens-codeblocks-mirror\codeblocks.git\src\sdk\manager.cpp:533
[debug]#5 0x619586df in CodeCompletion::CodeCompletion (this=0x11699070) at F:\jens-codeblocks-mirror\codeblocks.git\src\plugins\codecompletion\codecompletion.cpp:498
[debug]#6 0x619d6325 in PluginRegistrant<CodeCompletion>::CreatePlugin () at F:\jens-codeblocks-mirror\codeblocks.git\src\include\cbplugin.h:1115
[debug]#7 0x69346aa0 in PluginManager::LoadPlugin (this=0x115b74d8, pluginName=L"F:\\jens-codeblocks-mirror\\codeblocks.git\\src\\devel30\\share\\codeblocks\\plugins\\codecompletion.dll", plugElem0=0x115bc9d8) at F:\jens-codeblocks-mirror\codeblocks.git\src\sdk\pluginmanager.cpp:1098
[debug]#8 0x6934aa9b in PluginsConfigurationDlg::OnToggle (this=0x22f170, event=...) at F:\jens-codeblocks-mirror\codeblocks.git\src\sdk\pluginsconfigurationdlg.cpp:217
...

--- End code ---

It sounds like in our code, we need to release the in memory files?

--- Code: ---bool Manager::LoadResource(const wxString& file)
{
wxString resourceFile = ConfigManager::LocateDataFile(file, sdDataGlobal | sdDataUser);
wxString memoryFile = _T("memory:") + file;

if (wxFile::Access(resourceFile, wxFile::read) == false)
{
Get()->GetLogManager()->LogError(_("Manager failed to access XRC resource '") + resourceFile + _("'."));
return false;
}

// The code below forces a reload of the resource
// Currently unused...

// {
// wxMemoryFSHandler::RemoveFile(file);
// }
//#if wxABI_VERSION > 20601
// // unload old resources with the same name
// wxXmlResource::Get()->Unload(memoryFile);
//#endif

wxFile f(resourceFile, wxFile::read);
char *buf = nullptr;

try
{
size_t len = f.Length();
buf = new char[len];
f.Read(buf, len);
{
wxMemoryFSHandler::AddFile(file, buf, len);
}
if ( !wxXmlResource::Get()->Load(memoryFile) )
Get()->GetLogManager()->LogError(_("Manager failed to load XRC resource '") + resourceFile + _("'."));
delete[] buf;
return true;
}
catch (...)
{
delete[] buf;
Get()->GetLogManager()->LogError(_("Manager hardly failed to load XRC resource '") + resourceFile + _("'."));
return false;
}
}

--- End code ---

Any ideas?

ollydbg:
Enable the commented code snippets, I see that

--- Quote ---08:58:25: Trying to remove file 'resources.zip' from memory VFS, but it is not loaded!
08:58:25: Trying to remove file 'manager_resources.zip' from memory VFS, but it is not loaded!
08:58:27: Trying to remove file 'autosave.zip' from memory VFS, but it is not loaded!
08:58:28: Trying to remove file 'codecompletion.zip' from memory VFS, but it is not loaded!
08:58:29: Trying to remove file 'occurrenceshighlighting.zip' from memory VFS, but it is not loaded!
...

--- End quote ---
like messages happens.

So, we need to check whether those zip files were exists in VFS system, but I don't see which method I can use...
wxWidgets: wxFileSystemHandler Class Reference

ollydbg:
This is wx's source:

--- Code: ---// ----------------------------------------------------------------------------
// wxMemoryFSHandlerBase
// ----------------------------------------------------------------------------

class WXDLLIMPEXP_BASE wxMemoryFSHandlerBase : public wxFileSystemHandler
{
public:
wxMemoryFSHandlerBase();
virtual ~wxMemoryFSHandlerBase();

// Add file to list of files stored in memory. Stored data (bitmap, text or
// raw data) will be copied into private memory stream and available under
// name "memory:" + filename
static void AddFile(const wxString& filename, const wxString& textdata);
static void AddFile(const wxString& filename, const void *binarydata, size_t size);
static void AddFileWithMimeType(const wxString& filename,
const wxString& textdata,
const wxString& mimetype);
static void AddFileWithMimeType(const wxString& filename,
const void *binarydata, size_t size,
const wxString& mimetype);

// Remove file from memory FS and free occupied memory
static void RemoveFile(const wxString& filename);

virtual bool CanOpen(const wxString& location) wxOVERRIDE;
virtual wxFSFile* OpenFile(wxFileSystem& fs, const wxString& location) wxOVERRIDE;
virtual wxString FindFirst(const wxString& spec, int flags = 0) wxOVERRIDE;
virtual wxString FindNext() wxOVERRIDE;

protected:
// check that the given file is not already present in m_Hash; logs an
// error and returns false if it does exist
static bool CheckDoesntExist(const wxString& filename);

// the hash map indexed by the names of the files stored in the memory FS
static wxMemoryFSHash m_Hash;

// the file name currently being searched for, i.e. the argument of the
// last FindFirst() call or empty string if FindFirst() hasn't been called
// yet or FindNext() didn't find anything
wxString m_findArgument;

// iterator into m_Hash used by FindFirst/Next(), possibly m_Hash.end() or
// even invalid (can only be used when m_findArgument is not empty)
wxMemoryFSHash::const_iterator m_findIter;
};

// ----------------------------------------------------------------------------
// wxMemoryFSHandler
// ----------------------------------------------------------------------------

#if wxUSE_GUI

// add GUI-only operations to the base class
class WXDLLIMPEXP_CORE wxMemoryFSHandler : public wxMemoryFSHandlerBase
{
public:
// bring the base class versions into the scope, otherwise they would be
// inaccessible in wxMemoryFSHandler
// (unfortunately "using" can't be used as gcc 2.95 doesn't have it...)
static void AddFile(const wxString& filename, const wxString& textdata)
{
wxMemoryFSHandlerBase::AddFile(filename, textdata);
}

static void AddFile(const wxString& filename,
const void *binarydata,
size_t size)
{
wxMemoryFSHandlerBase::AddFile(filename, binarydata, size);
}
static void AddFileWithMimeType(const wxString& filename,
const wxString& textdata,
const wxString& mimetype)
{
wxMemoryFSHandlerBase::AddFileWithMimeType(filename,
textdata,
mimetype);
}
static void AddFileWithMimeType(const wxString& filename,
const void *binarydata, size_t size,
const wxString& mimetype)
{
wxMemoryFSHandlerBase::AddFileWithMimeType(filename,
binarydata, size,
mimetype);
}

#if wxUSE_IMAGE
static void AddFile(const wxString& filename,
const wxImage& image,
wxBitmapType type);

static void AddFile(const wxString& filename,
const wxBitmap& bitmap,
wxBitmapType type);
#endif // wxUSE_IMAGE

};

#else // !wxUSE_GUI

// just the same thing as the base class in wxBase
class WXDLLIMPEXP_BASE wxMemoryFSHandler : public wxMemoryFSHandlerBase
{
};

#endif // wxUSE_GUI/!wxUSE_GUI

--- End code ---

Note that the function

--- Code: ---static bool CheckDoesntExist(const wxString& filename);
--- End code ---

But this function is protected, so we can't access it, this gives the dilemma：

1, if we try to remove a file which does not exists in the system, we get a log message from wx.
2, if we try to add a file which the same file already exists in the system, we also get a log message from wx.

So, how can we handle this? Do we need to always remove the file when a plugin is unloaded?

ollydbg:
We have a bool Manager::LoadResource(const wxString& file) function, but do we need to have a function UnloadResource() which we need to call from the destructor of a plugin?

--- Code: ---ProjectsImporter::ProjectsImporter()
{
//ctor
if (!Manager::LoadResource(_T("projectsimporter.zip")))
NotifyMissingFile(_T("projectsimporter.zip"));
}

ProjectsImporter::~ProjectsImporter()
{
//dtor
Manager::UnloadResource(...);
}

--- End code ---

MortenMacFly:

--- Quote from: ollydbg on February 17, 2016, 02:18:32 am ---But this function is protected, so we can't access it, this gives the dilemma：

--- End quote ---
Except if we make our own class cbMemoryFSHandlerBase and derive from it... if that's feasible in this context.

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