22d6efa851
git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@3296 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
71 lines
2.6 KiB
TeX
71 lines
2.6 KiB
TeX
\section{File Systems}\label{fs}
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The wxHTML library uses a {\bf virtual file systems} mechanism
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similar to the one used in Midnight Commander, Dos Navigator,
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FAR or almost any modern file manager. (Do you remember? You can
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press enter on ZIP file and its contents is displayed as if it
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were a local directory...)
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\wxheading{Classes}
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Three classes are used in order to provide full VFS:
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\begin{itemize}\itemsep=0pt
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\item The \helpref{wxFSFile}{wxfsfile} class provides information
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on opened file (name, input stream, mime type and anchor).
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\item The \helpref{wxFileSystem}{wxfilesystem} class is the interface.
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Its main methods are ChangePathTo() and OpenFile(). This class
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is most often used by the end user.
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\item The \helpref{wxFileSystemHandler}{wxfilesystemhandler} is the core
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if VFS mechanism. You can derive your own handler and pass it to
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wxFileSystem's AddHandler() method. In the new handler you only need to
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overwrite OpenFile() and CanOpen() methods.
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\end{itemize}
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\wxheading{Locations}
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Locations (aka filenames aka addresses) are constructed from 4 parts:
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\begin{itemize}\itemsep=0pt
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\item {\bf protocol} - handler can recognize if it is able to open a
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file by checking its protocol. Examples are "http", "file" or "ftp".
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\item {\bf right location} - is the name of file within the protocol.
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In "http://www.wxwindows.org/index.html" the right location is "//www.wxwindows.org/index.html".
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\item {\bf anchor} - anchor is optional and is usually not present.
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In "index.htm\#chapter2" the anchor is "chapter2".
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\item {\bf left location} - this is usually an empty string.
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It is used by 'local' protocols such as ZIP.
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See Combined Protocols paragraph for details.
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\end{itemize}
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\wxheading{Combined Protocols}
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Left location pretends protocol in URL string.
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It's not used by global protocols like HTTP but it's used
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by local ones - for example you can see this address:
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file:archives/cpp\_doc.zip\#zip:reference/fopen.htm\#syntax
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In this example, protocol is "zip", left location is
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"reference/fopen.htm", anchor is "syntax" and right location
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is "file:archives/cpp_doc.zip". It is used by zip handler
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to determine in what file this particular zip VFS is stored.
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In fact there are two protocols used in this example: zip and file.
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You can construct even more complicated addresses like this one:
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http://www.archives.org/myarchive.zip\#zip:local/docs/cpp/stdio.zip\#zip:index.htm
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In this example you access zip VFS stdio.zip stored in another zip (myarchive.zip)
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which is at WWW.
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\wxheading{File Systems Included in wxHTML}
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\begin{enumerate}\itemsep=0pt
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\item Local files
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\item HTTP protocol
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\item FTP protocol
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\item .ZIP archives
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\end{enumerate}
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