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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-15 18:07:41 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-15 18:07:41 +0000
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Adding upstream version 2.7.6.upstream/2.7.6
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
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+:mod:`apt.cache` --- The Cache class
+=====================================
+.. automodule:: apt.cache
+
+The Cache class
+---------------
+
+.. autoclass:: Cache
+ :members:
+ :undoc-members:
+
+ .. describe:: cache[pkgname]
+
+ Return a :class:`Package()` for the package with the name *pkgname*.
+
+Example
+^^^^^^^
+
+The following example shows how to load the cache, update it, and upgrade
+all the packages on the system::
+
+ import apt
+ import apt.progress
+
+ # First of all, open the cache
+ cache = apt.Cache()
+ # Now, lets update the package list
+ cache.update()
+ # We need to re-open the cache because it needs to read the package list
+ cache.open(None)
+ # Now we can do the same as 'apt-get upgrade' does
+ cache.upgrade()
+ # or we can play 'apt-get dist-upgrade'
+ cache.upgrade(True)
+ # Q: Why does nothing happen?
+ # A: You forgot to call commit()!
+ cache.commit(apt.progress.TextFetchProgress(),
+ apt.progress.InstallProgress())
+
+
+
+Working with Filters
+--------------------
+.. autoclass:: Filter
+ :members:
+ :inherited-members:
+ :undoc-members:
+
+.. autoclass:: MarkedChangesFilter
+ :members:
+ :inherited-members:
+ :undoc-members:
+
+.. autoclass:: FilteredCache
+ :members:
+ :inherited-members:
+ :undoc-members:
+
+
+Example
+^^^^^^^
+
+This is an example for a filtered cache, which only allows access to the
+packages whose state has been changed, eg. packages marked for installation::
+
+ >>> from apt.cache import FilteredCache, Cache, MarkedChangesFilter
+ >>> cache = apt.Cache()
+ >>> changed = apt.FilteredCache(cache)
+ >>> changed.set_filter(MarkedChangesFilter())
+ >>> print(len(changed) == len(cache.get_changes())) # Both need to have same length
+ True
+
+The ProblemResolver class
+--------------------------
+
+.. autoclass:: ProblemResolver
+ :members:
+
+Exceptions
+----------
+.. autoexception:: FetchCancelledException
+.. autoexception:: FetchFailedException
+.. autoexception:: LockFailedException