The wxHTML library uses a virtual file systems mechanism similar to the one used in Midnight Commander, Dos Navigator, FAR or almost any modern file manager. (Do you remember? You can press enter on ZIP file and its contents is displayed as if it were a local directory...)
Classes
Three classes are used in order to provide full VFS:
Locations
Locations (aka filenames aka addresses) are constructed from 4 parts:
Combined Protocols
Left location pretends protocol in URL string. It's not used by global protocols like HTTP but it's used by local ones - for example you can see this address:
file:archives/cpp_doc.zip#zip:reference/fopen.htm#syntax
In this example, protocol is "zip", left location is "reference/fopen.htm", anchor is "syntax" and right location is "file:archives/cpp_doc.zip". It is used by zip handler to determine in what file this particular zip VFS is stored.
In fact there are two protocols used in this example: zip and file. You can construct even more complicated addresses like this one:
http://www.archives.org/myarchive.zip#zip:local/docs/cpp/stdio.zip#zip:index.htm
In this example you access zip VFS stdio.zip stored in another zip (myarchive.zip) which is at WWW.
File Systems Included in wxHTML
Following VFS handlers are part of wxWindows so far:
wxInternetFSHandler | Handler for accessing documents via HTTP or FTP protocols. Include file is <wx/fs_inet.h>. |
wxZipFSHandler | Handler for ZIP archives. Include file is <wx/fs_zip.h>. URL is in form "archive.zip#zip:filename". |
wxMemoryFSHandler | This handler allows you to access data stored in memory (such as bitmaps) as if they were regular files. See wxMemoryFSHandler documentation for details. Include file is <wx/fs_mem.h>. UURL is prefixed with memory:, e.g. "memory:myfile.htm" |
In addition, wxFileSystem can access local files.
Use wxFileSystem::AddHandler to initialize a handler, for example:
#include <wx/fs_mem.h> ... bool MyApp::OnInit() { wxFileSystem::AddHandler(new wxMemoryFSHandler); ...