wxFileSystem

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. It allows the user to access data stored in archives as if they were ordinary files. On-the-fly generated files that exist only in memory are also supported.

Classes

Three classes are used in order to provide virtual file systems mechanism:

Locations

Locations (aka filenames aka addresses) are constructed from four parts:

Combined Protocols

The left location precedes the protocol in the URL string. It is not used by global protocols like HTTP but it becomes handy when nesting protocols - for example you may want to access files in a ZIP archive:

file:archives/cpp_doc.zip#zip:reference/fopen.htm#syntax

In this example, the protocol is "zip", right location is "reference/fopen.htm", anchor is "syntax" and left location is "file:archives/cpp_doc.zip".

There are two protocols used in this example: "zip" and "file".

File Systems Included in wxHTML

The following virtual file system handlers are part of wxWidgets so far:

wxInternetFSHandler A handler for accessing documents via HTTP or FTP protocols. Include file is <wx/fs_inet.h>.
wxZipFSHandler A 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>. URL is prefixed with memory:, e.g. "memory:myfile.htm"

In addition, wxFileSystem itself can access local files.

Initializing file system handlers

Use wxFileSystem::AddHandler to initialize a handler, for example:

#include <wx/fs_mem.h>

...

bool MyApp::OnInit()
{
    wxFileSystem::AddHandler(new wxMemoryFSHandler);
...
}
ymasuda 平成17年11月19日