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<?xml version="1.0" encoding="UTF-8"?>
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<html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en">
<head>
<title>KAutoSaveFile</title>
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<img alt ="" src="../common/top-kde.jpg"/>
KDE 4.9 PyKDE API Reference
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<li>KDE's Python API</li>
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<h1>KAutoSaveFile Class Reference</h1>
<code>from PyKDE4.kdecore import *</code>
<p>
Inherits: QFile → QIODevice → QObject<br />
<h2>Detailed Description</h2>
<p>\class KAutoSaveFile kautosavefile.h <KAutoSaveFile>
</p>
<p>
Creates and manages a temporary "auto-save" file.
Autosave files are temporary files that applications use to store
the unsaved data in a file they have open for
editing. KAutoSaveFile allows you to easily create and manage such
files, as well as to recover the unsaved data left over by a
crashed or otherwise gone process.
</p>
<p>
Each KAutoSaveFile object is associated with one specific file that
the application holds open. KAutoSaveFile is also a QObject, so it
can be reparented to the actual opened file object, so as to manage
the lifetime of the temporary file.
</p>
<p>
Typical use consists of:
- verifying whether stale autosave files exist for the opened file
- deciding whether to recover the old, autosaved data
- if not recovering, creating a KAutoSaveFile object for the opened file
- during normal execution of the program, periodically save unsaved
data into the KAutoSaveFile file.
</p>
<p>
KAutoSaveFile holds a lock on the autosave file, so it's safe to
delete the file and recreate it later. Because of that, disposing
of stale autosave files should be done with releaseLock(). No lock is
held on the managed file.
</p>
<p>
Examples:
Opening a new file:
<pre class="fragment">
void Document.open(const KUrl &url)
{
// check whether autosave files exist:
QList<KAutoSaveFile *> staleFiles = KAutoSaveFile.staleFiles(url);
if (!staleFiles.isEmpty()) {
if (KMessageBox.questionYesNo(parent,
"Auto-saved files exist. Do you want to recover them now?",
"File Recovery",
"Recover", "Don't recover") == KMessage.Yes) {
recoverFiles(staleFiles);
return;
} else {
// remove the stale files
foreach (KAutoSaveFile *stale, staleFiles) {
stale->open(QIODevice.ReadWrite);
delete stale;
}
}
}
// create new autosave object
m_autosave = new KAutoSaveFile(url, this);
// continue the process of opening file 'url'
...
}
</pre>
</p>
<p>
The function recoverFiles could loop over the list of files and do this:
<pre class="fragment">
foreach (KAutoSaveFile *stale, staleFiles) {
if (!stale->open(QIODevice.ReadWrite)) {
// show an error message; we could not steal the lockfile
// maybe another application got to the file before us?
delete stale;
continue;
}
Document *doc = new Document;
doc->m_autosave = stale;
stale->setParent(doc); // reparent
doc->setUrl(stale->managedFile());
doc->setContents(stale->readAll());
doc->setState(Document.Modified); // mark it as modified and unsaved
documentManager->addDocument(doc);
}
</pre>
</p>
<p>
If the file is unsaved, periodically write the contents to the save file:
<pre class="fragment">
if (!m_autosave->isOpen() && !m_autosave->open(QIODevice.ReadWrite)) {
// show error: could not open the autosave file
}
m_autosave->write(contents());
</pre>
</p>
<p>
When the user saves the file, the autosaved file is no longer
necessary and can be removed or emptied.
<pre class="fragment">
m_autosave->resize(0); // leaves the file open
</pre>
</p>
<p>
<pre class="fragment">
m_autosave->remove(); // closes the file
</pre>
</p>
<p>
<dl class="author" compact><dt><b>Author:</b></dt><dd> Jacob R Rideout <kde@jacobrideout.net> </dd></dl>
</p>
<table border="0" cellpadding="0" cellspacing="0"><tr><td colspan="2"><br><h2>Methods</h2></td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top"> </td><td class="memItemRight" valign="bottom"><a class="el" href="#KAutoSaveFile">__init__</a> (self, <a href="../kdecore/KUrl.html">KUrl</a> filename, QObject parent=0)</td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top"> </td><td class="memItemRight" valign="bottom"><a class="el" href="#KAutoSaveFile">__init__</a> (self, QObject parent=0)</td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top"> </td><td class="memItemRight" valign="bottom"><a class="el" href="#KAutoSaveFile">__init__</a> (self, <a href="../kdecore/KAutoSaveFile.html">KAutoSaveFile</a> a0)</td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top"><a href="../kdecore/KUrl.html">KUrl</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="#managedFile">managedFile</a> (self)</td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top">bool </td><td class="memItemRight" valign="bottom"><a class="el" href="#open">open</a> (self, QIODevice::OpenMode openmode)</td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top"> </td><td class="memItemRight" valign="bottom"><a class="el" href="#releaseLock">releaseLock</a> (self)</td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top"> </td><td class="memItemRight" valign="bottom"><a class="el" href="#setManagedFile">setManagedFile</a> (self, <a href="../kdecore/KUrl.html">KUrl</a> filename)</td></tr>
<tr><td colspan="2"><br><h2>Static Methods</h2></td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top">[<a href="../kdecore/KAutoSaveFile.html">KAutoSaveFile</a>] </td><td class="memItemRight" valign="bottom"><a class="el" href="#allStaleFiles">allStaleFiles</a> (QString applicationName=QString())</td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top">[<a href="../kdecore/KAutoSaveFile.html">KAutoSaveFile</a>] </td><td class="memItemRight" valign="bottom"><a class="el" href="#staleFiles">staleFiles</a> (<a href="../kdecore/KUrl.html">KUrl</a> filename, QString applicationName=QString())</td></tr>
</table>
<hr><h2>Method Documentation</h2><a class="anchor" name="KAutoSaveFile"></a>
<div class="memitem">
<div class="memproto">
<table class="memname"><tr>
<td class="memname">__init__</td>
<td>(</td>
<td class="paramtype"> <em>self</em>, </td>
<td class="paramname"></td>
</tr><tr>
<td class="memname"></td>
<td></td>
<td class="paramtype"><a href="../kdecore/KUrl.html">KUrl</a> </td>
<td class="paramname"><em>filename</em>, </td>
</tr>
<tr>
<td class="memname"></td>
<td></td>
<td class="paramtype">QObject </td>
<td class="paramname"><em>parent=0</em></td>
</tr>
<tr>
<td></td>
<td>)</td>
<td></td>
<td></td>
<td width="100%"> </td>
</tr></table>
</div>
<div class="memdoc"><p>Constructs a KAutoSaveFile for file <b>filename.</b> The temporary
file is not opened or created until actually needed. The file
<b>filename</b> does not have to exist for KAutoSaveFile to be
constructed (if it exists, it will not be touched).
</p>
<p>
</p><dl compact><dt><b>Parameters:</b></dt><dd>
<table border="0" cellspacing="2" cellpadding="0">
<tr><td></td><td valign="top"><em>filename</em> </td><td> the filename that this KAutoSaveFile refers to
<tr><td></td><td valign="top"><em>parent</em> </td><td> the parent object
</td></tr>
</table></dl>
<p>
</p></div></div><a class="anchor" name="KAutoSaveFile"></a>
<div class="memitem">
<div class="memproto">
<table class="memname"><tr>
<td class="memname">__init__</td>
<td>(</td>
<td class="paramtype"> <em>self</em>, </td>
<td class="paramname"></td>
</tr><tr>
<td class="memname"></td>
<td></td>
<td class="paramtype">QObject </td>
<td class="paramname"><em>parent=0</em></td>
</tr>
<tr>
<td></td>
<td>)</td>
<td></td>
<td></td>
<td width="100%"> </td>
</tr></table>
</div>
<div class="memdoc"><p>
Constructs a KAutoSaveFile object. Note that you need to call
setManagedFile() before calling open().
</p>
<p>
</p><dl compact><dt><b>Parameters:</b></dt><dd>
<table border="0" cellspacing="2" cellpadding="0">
<tr><td></td><td valign="top"><em>parent</em> </td><td> the parent object
</td></tr>
</table></dl>
<p>
</p></div></div><a class="anchor" name="KAutoSaveFile"></a>
<div class="memitem">
<div class="memproto">
<table class="memname"><tr>
<td class="memname">__init__</td>
<td>(</td>
<td class="paramtype"> <em>self</em>, </td>
<td class="paramname"></td>
</tr><tr>
<td class="memname"></td>
<td></td>
<td class="paramtype"><a href="../kdecore/KAutoSaveFile.html">KAutoSaveFile</a> </td>
<td class="paramname"><em>a0</em></td>
</tr>
<tr>
<td></td>
<td>)</td>
<td></td>
<td></td>
<td width="100%"> </td>
</tr></table>
</div>
<div class="memdoc"></div></div><a class="anchor" name="managedFile"></a>
<div class="memitem">
<div class="memproto">
<table class="memname"><tr>
<td class="memname"><a href="../kdecore/KUrl.html">KUrl</a> managedFile</td>
<td>(</td>
<td class="paramtype"> </td>
<td class="paramname"><em>self</em> )</td>
<td width="100%"> </td>
</tr>
</table>
</div>
<div class="memdoc"><p>Retrieves the URL of the file managed by KAutoSaveFile. This
is the same URL that was given to setManagedFile() or the
KAutoSaveFile constructor.
</p>
<p>
This is the name of the real file being edited by the
application. To get the name of the temporary file where data
can be saved, use fileName() (after you have called open()).
</p></div></div><a class="anchor" name="open"></a>
<div class="memitem">
<div class="memproto">
<table class="memname"><tr>
<td class="memname">bool open</td>
<td>(</td>
<td class="paramtype"> <em>self</em>, </td>
<td class="paramname"></td>
</tr><tr>
<td class="memname"></td>
<td></td>
<td class="paramtype">QIODevice::OpenMode </td>
<td class="paramname"><em>openmode</em></td>
</tr>
<tr>
<td></td>
<td>)</td>
<td></td>
<td></td>
<td width="100%"> </td>
</tr></table>
</div>
<div class="memdoc"><p>Opens the autosave file and locks it if it wasn't already
locked. The name of the temporary file where data can be saved
to will be set by this function and can be retrieved with
fileName(). It will not change unless releaseLock() is called. No
other application will attempt to edit such a file either while
the lock is held.
</p>
<p>
</p><dl compact><dt><b>Parameters:</b></dt><dd>
<table border="0" cellspacing="2" cellpadding="0">
<tr><td></td><td valign="top"><em>openmode</em> </td><td> the mode that should be used to open the file,
probably QIODevice.ReadWrite
</td></tr> </table></dl>
<p> <dl class="return" compact><dt><b>Returns:</b></dt><dd> true if the file could be opened (= locked and
created), false if the operation failed
</dd></dl>
</p></div></div><a class="anchor" name="releaseLock"></a>
<div class="memitem">
<div class="memproto">
<table class="memname"><tr>
<td class="memname"> releaseLock</td>
<td>(</td>
<td class="paramtype"> </td>
<td class="paramname"><em>self</em> )</td>
<td width="100%"> </td>
</tr>
</table>
</div>
<div class="memdoc"><p>Closes the autosave file resource and removes the lock
file. The file name returned by fileName() will no longer be
protected and can be overwritten by another application at any
time. To obtain a new lock, call open() again.
</p>
<p>
This function calls remove(), so the autosave temporary file
will be removed too.
</p></div></div><a class="anchor" name="setManagedFile"></a>
<div class="memitem">
<div class="memproto">
<table class="memname"><tr>
<td class="memname"> setManagedFile</td>
<td>(</td>
<td class="paramtype"> <em>self</em>, </td>
<td class="paramname"></td>
</tr><tr>
<td class="memname"></td>
<td></td>
<td class="paramtype"><a href="../kdecore/KUrl.html">KUrl</a> </td>
<td class="paramname"><em>filename</em></td>
</tr>
<tr>
<td></td>
<td>)</td>
<td></td>
<td></td>
<td width="100%"> </td>
</tr></table>
</div>
<div class="memdoc"><p>Sets the URL of the file managed by KAutoSaveFile. This should
be the name of the real file being edited by the application.
If the file was previously set, this function calls releaseLock().
</p>
<p>
</p><dl compact><dt><b>Parameters:</b></dt><dd>
<table border="0" cellspacing="2" cellpadding="0">
<tr><td></td><td valign="top"><em>filename</em> </td><td> the filename that this KAutoSaveFile refers to
</td></tr>
</table></dl>
<p>
</p></div></div><hr><h2>Static Method Documentation</h2><a class="anchor" name="allStaleFiles"></a>
<div class="memitem">
<div class="memproto">
<table class="memname"><tr>
<td class="memname">[<a href="../kdecore/KAutoSaveFile.html">KAutoSaveFile</a>] allStaleFiles</td>
<td>(</td>
<td class="paramtype">QString </td>
<td class="paramname"><em>applicationName=QString()</em></td>
</tr>
<tr>
<td></td>
<td>)</td>
<td></td>
<td></td>
<td width="100%"> </td>
</tr></table>
</div>
<div class="memdoc"><p>Returns all stale autosave files left behind by crashed or
otherwise gone instances of this application.
</p>
<p>
If not given, the application name is obtained from
QCoreApplication, so be sure to have set it correctly before
calling this function.
</p>
<p>
See staleFiles() for information on the returned objects.
</p></div></div><a class="anchor" name="staleFiles"></a>
<div class="memitem">
<div class="memproto">
<table class="memname"><tr>
<td class="memname">[<a href="../kdecore/KAutoSaveFile.html">KAutoSaveFile</a>] staleFiles</td>
<td>(</td>
<td class="paramtype"><a href="../kdecore/KUrl.html">KUrl</a> </td>
<td class="paramname"><em>filename</em>, </td>
</tr>
<tr>
<td class="memname"></td>
<td></td>
<td class="paramtype">QString </td>
<td class="paramname"><em>applicationName=QString()</em></td>
</tr>
<tr>
<td></td>
<td>)</td>
<td></td>
<td></td>
<td width="100%"> </td>
</tr></table>
</div>
<div class="memdoc"><p>Checks for stale autosave files for <b>filename.</b> Returns a list
of autosave files that contain autosaved data left behind by
other instances of the application, due to crashing or
otherwise uncleanly exiting.
</p>
<p>
It is the application's job to determine what to do with such
unsaved data. Generally, this is done by asking the user if he
wants to see the recovered data, and then allowing the user to
save if he wants to.
</p>
<p>
If not given, the application name is obtained from
QCoreApplication, so be sure to have set it correctly before
calling this function.
</p>
<p>
This function returns a list of unopened KAutoSaveFile
objects. By calling open() on them, the application will steal
the lock. Subsequent releaseLock() or deleting of the object will
then erase the stale autosave file.
</p></div></div>
</div>
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