* apt-pkg/deb/dpkgpm.cc:

  - apport integration added, this means that a apport
    report is written on dpkg failures
* merged from debian/unstable, remaining changes:
  - maintainer field changed

* merged the debian/experimental changes back
  into the debian/sid branch
* merged from Christian Perrier:
  * mr.po: New Marathi translation  Closes: #416806
  * zh_CN.po: Updated by Eric Pareja  Closes: #416822
  * tl.po: Updated by Eric Pareja   Closes: #416638
  * gl.po: Updated by Jacobo Tarrio
  * da.po: Updated by Claus Hindsgaul
  * fr.po: Remove a non-breakable space for usability
  * ru.po: Updated Russian translation. Closes: #405476
  * *.po: Unfuzzy after upstream typo corrections
* buildlib/archtable:
  - added support for sh3/sh4 (closes: #424870)
  - added support for m32r (closes: #394096)
* buildlib/systemtable:
  - added support for lpia
* configure.in:
  - check systemtable for architecture mapping too
* fix error in AutocleanInterval, closes: #319339
  (thanks to Israel G. Lugo for the patch)
* add "purge" commandline argument, closes: #133421)
  (thanks to Julien Danjou for the patch)
* add "purge" commandline argument, closes: #133421)
  (thanks to Julien Danjou for the patch)
* fix FTBFS with gcc 4.3, closes: #417090
  (thanks to Martin Michlmayr for the patch)
* add --dsc-only option, thanks to K. Richard Pixley
* Removed the more leftover #pragma interface/implementation
  closes: #306937 (thanks to Andreas Henriksson for the patch)

* ABI library name change because its build against
  new glibc
* implement SourceVer() in pkgRecords 
   (thanks to Daniel Burrows for the patch!)
* apt-pkg/algorithm.cc:
  - use clog for all debugging
  - only increase the score of installed applications if they 
    are not obsolete 
  - fix resolver bug on removal triggered by weak-dependencies 
    with or-groups
* methods/http.cc:
  - send apt version in User-Agent
* apt-pkg/deb/debrecords.cc:
  - fix SHA1Hash() return value
* apt-pkg/cdrom.cc:
  - only unmount if APT::CDROM::NoMount is false
* methods/cdrom.cc:  
  - only umount if it was mounted by the method before
  - if decompression of a index fails, delete the index 
  * vi.po: Updated to 515t. Closes: #426976
  * eu.po: Updated to 515t. Closes: #423766
  * pt.po: 515t. Closes: #423111
  * fr.po: Updated by Christian Perrier
  * Update all PO and the POT. Gives 513t2f for formerly
    complete translations
* Package that contains tall the new features
* Removed all #pragma interface/implementation
* Branch that contains tall the new features:
* translated package descriptions
* task install support
* automatic dependency removal (thanks to Daniel Burrows)
* merged support for the new dpkg "Breaks" field 
  (thanks to Ian Jackson)
* handle network failures more gracefully on "update"
* support for unattended-upgrades (via unattended-upgrades
  package)
* added apt-transport-https method
  - ca.po: Updated to 514t
  - be.po: Updated to 514t
  - it.po: Updated to 514t
  - hu.po: Updated to 514t
  - zh_TW.po: Updated to 514t
  - ar.po: Updated to 293t221u.
  - ru.po: Updated to 514t. Closes: #392466
  - nb.po: Updated to 514t. Closes: #392466
  - pt.po: Updated to 514t. Closes: #393199
  - fr.po: One spelling error corrected: s/accèder/accéder
  - km.po: Updated to 514t.
  - ko.po: Updated to 514t.
  - bg.po: Updated to 514t.
  - de.po: Updated to 514t.
  - en_GB.po: Updated to 514t.
* debian/control:
  - depend on debian-archive-keyring to offer clean upgrade path 
    (closes: #386800)
* merged "install-recommends" branch (ABI break): 
  - new "--install-recommends"
  - install new recommends on "upgrade" if --install-recommends is 
    given
  - new "--fix-policy" option to install all packages with unmet
    important dependencies (usefull with --install-recommends to
    see what not-installed recommends are on the system)
  - fix of recommended packages display (only show CandidateVersion
    fix or-group handling)
* merged "install-task" branch (use with "apt-get install taskname^")
* Applied patch from Daniel Schepler to make apt bin-NMU able.
* apt-pkg/acquire-item.cc:
  - fix reversed logic of the "Acquire::PDiffs" option
* apt-pkg/contrib/sha256.cc:
  - applied patch to fix unaligned access problem. Closes: #367417
    (thanks to David Mosberger)
* apt-pkg/contrib/sha256.{cc,h},hashes.{cc,h}: support for sha256 
  (thanks to Anthony Towns)
* ftparchive/cachedb.{cc,h},writer.{cc,h}: optimizations 
  (thanks to Anthony Towns)
* apt pdiff support from experimental merged
* apt-pkg/deb/dpkgpm.cc: wording fixes (thanks to Matt Zimmerman)
  - fix error in dpkg interaction (closes: #364513, thanks to Martin Dickopp)

1 files changed, 696 insertions, 31 deletions

diff --git a/apt-pkg/acquire-item.h b/apt-pkg/acquire-item.h
index 1885f7beb..233cbdda9 100644
--- a/apt-pkg/acquire-item.h
+++ b/apt-pkg/acquire-item.h
@@ -28,72 +28,503 @@
 #include <apt-pkg/indexrecords.h>
 
 
-// Item to acquire
+/** \addtogroup acquire
+ *  @{
+ *
+ *  \file acquire-item.h
+ */
+
+/** \brief Represents the process by which a pkgAcquire object should
+ *  retrieve a file or a collection of files.
+ *
+ *  By convention, Item subclasses should insert themselves into the
+ *  acquire queue when they are created by calling QueueURI(), and
+ *  remove themselves by calling Dequeue() when either Done() or
+ *  Failed() is invoked.  Item objects are also responsible for
+ *  notifying the download progress indicator (accessible via
+ *  #Owner->Log) of their status.
+ *
+ *  \see pkgAcquire
+ */
 class pkgAcquire::Item
 {  
    protected:
    
-   // Some private helper methods for registering URIs
+   /** \brief The acquire object with which this item is associated. */
    pkgAcquire *Owner;
+
+   /** \brief Insert this item into its owner's queue.
+    *
+    *  \param ItemDesc Metadata about this item (its URI and
+    *  description).
+    */
    inline void QueueURI(ItemDesc &Item)
                  {Owner->Enqueue(Item);};
+
+   /** \brief Remove this item from its owner's queue. */
    inline void Dequeue() {Owner->Dequeue(this);};
    
-   // Safe rename function with timestamp preservation
+   /** \brief Rename a file without modifying its timestamp.
+    *
+    *  Many item methods call this as their final action.
+    *
+    *  \param From The file to be renamed.
+    *
+    *  \param To The new name of #From.  If #To exists it will be
+    *  overwritten.
+    */
    void Rename(string From,string To);
    
    public:
 
-   // State of the item
-   enum {StatIdle, StatFetching, StatDone, StatError, 
-	 StatAuthError, StatTransientNetworkError} Status;
+   /** \brief The current status of this item. */
+   enum ItemState
+     {
+       /** \brief The item is waiting to be downloaded. */
+       StatIdle,
+
+       /** \brief The item is currently being downloaded. */
+       StatFetching,
+
+       /** \brief The item has been successfully downloaded. */
+       StatDone,
+
+       /** \brief An error was encountered while downloading this
+	*  item.
+	*/
+       StatError,
+
+       /** \brief The item was downloaded but its authenticity could
+	*  not be verified.
+	*/
+       StatAuthError,
+
+       /** \brief The item was could not be downloaded because of 
+	*  a transient network error (e.g. network down)
+	*/
+       StatTransientNetworkError
+     } Status;
+
+   /** \brief Contains a textual description of the error encountered
+    *  if #Status is #StatError or #StatAuthError.
+    */
    string ErrorText;
+
+   /** \brief The size of the object to fetch. */
    unsigned long FileSize;
-   unsigned long PartialSize;   
+
+   /** \brief How much of the object was already fetched. */
+   unsigned long PartialSize;
+
+   /** \brief If not \b NULL, contains the name of a subprocess that
+    *  is operating on this object (for instance, "gzip" or "gpgv").
+    */
    const char *Mode;
+
+   /** \brief A client-supplied unique identifier.
+    * 
+    *  This field is initalized to 0; it is meant to be filled in by
+    *  clients that wish to use it to uniquely identify items.
+    *
+    *  \todo it's unused in apt itself
+    */
    unsigned long ID;
+
+   /** \brief If \b true, the entire object has been successfully fetched.
+    *
+    *  Subclasses should set this to \b true when appropriate.
+    */
    bool Complete;
+
+   /** \brief If \b true, the URI of this object is "local".
+    *
+    *  The only effect of this field is to exclude the object from the
+    *  download progress indicator's overall statistics.
+    */
    bool Local;
    string UsedMirror;
 
-   // Number of queues we are inserted into
+   /** \brief The number of fetch queues into which this item has been
+    *  inserted.
+    *
+    *  There is one queue for each source from which an item could be
+    *  downloaded.
+    *
+    *  \sa pkgAcquire
+    */
    unsigned int QueueCounter;
    
-   // File to write the fetch into
+   /** \brief The name of the file into which the retrieved object
+    *  will be written.
+    */
    string DestFile;
 
-   // Action members invoked by the worker
+   /** \brief Invoked by the acquire worker when the object couldn't
+    *  be fetched.
+    *
+    *  This is a branch of the continuation of the fetch process.
+    *
+    *  \param Message An RFC822-formatted message from the acquire
+    *  method describing what went wrong.  Use LookupTag() to parse
+    *  it.
+    *
+    *  \param Cnf The method via which the worker tried to fetch this object.
+    *
+    *  \sa pkgAcqMethod
+    */
    virtual void Failed(string Message,pkgAcquire::MethodConfig *Cnf);
+
+   /** \brief Invoked by the acquire worker when the object was
+    *  fetched successfully.
+    *
+    *  Note that the object might \e not have been written to
+    *  DestFile; check for the presence of an Alt-Filename entry in
+    *  Message to find the file to which it was really written.
+    *
+    *  Done is often used to switch from one stage of the processing
+    *  to the next (e.g. fetching, unpacking, copying).  It is one
+    *  branch of the continuation of the fetch process.
+    *
+    *  \param Message Data from the acquire method.  Use LookupTag()
+    *  to parse it.
+    *  \param Size The size of the object that was fetched.
+    *  \param Md5Hash The MD5Sum of the object that was fetched.
+    *  \param Cnf The method via which the object was fetched.
+    *
+    *  \sa pkgAcqMethod
+    */
    virtual void Done(string Message,unsigned long Size,string Md5Hash,
 		     pkgAcquire::MethodConfig *Cnf);
+
+   /** \brief Invoked when the worker starts to fetch this object.
+    *
+    *  \param Message RFC822-formatted data from the worker process.
+    *  Use LookupTag() to parse it.
+    *
+    *  \param Size The size of the object being fetched.
+    *
+    *  \sa pkgAcqMethod
+    */
    virtual void Start(string Message,unsigned long Size);
+
+   /** \brief Custom headers to be sent to the fetch process.
+    *
+    *  \return a string containing RFC822-style headers that are to be
+    *  inserted into the 600 URI Acquire message sent to the fetch
+    *  subprocess.  The headers are inserted after a newline-less
+    *  line, so they should (if nonempty) have a leading newline and
+    *  no trailing newline.
+    */
    virtual string Custom600Headers() {return string();};
+
+   /** \brief A "descriptive" URI-like string.
+    *
+    *  \return a URI that should be used to describe what is being fetched.
+    */
    virtual string DescURI() = 0;
+   /** \brief Short item description.
+    *
+    *  \return a brief description of the object being fetched.
+    */
    virtual string ShortDesc() {return DescURI();}
+
+   /** \brief Invoked by the worker when the download is completely done. */
    virtual void Finished() {};
    
-   // Inquire functions
+   /** \brief MD5Sum.
+    *
+    *  \return the MD5Sum of this object, if applicable; otherwise, an
+    *  empty string.
+    */
    virtual string MD5Sum() {return string();};
+
+   /** \return the acquire process with which this item is associated. */
    pkgAcquire *GetOwner() {return Owner;};
+
+   /** \return \b true if this object is being fetched from a trusted source. */
    virtual bool IsTrusted() {return false;};
    
    // report mirror problems
+   /** \brief Report mirror problem
+    * 
+    *  This allows reporting mirror failures back to a centralized
+    *  server. The apt-report-mirror-failure script is called for this
+    * 
+    *  \param FailCode A short failure string that is send
+    */
    void ReportMirrorFailure(string FailCode);
 
+
+   /** \brief Initialize an item.
+    *
+    *  Adds the item to the list of items known to the acquire
+    *  process, but does not place it into any fetch queues (you must
+    *  manually invoke QueueURI() to do so).
+    *
+    *  Initializes all fields of the item other than Owner to 0,
+    *  false, or the empty string.
+    *
+    *  \param Owner The new owner of this item.
+    */
    Item(pkgAcquire *Owner);
+
+   /** \brief Remove this item from its owner's queue by invoking
+    *  pkgAcquire::Remove.
+    */
    virtual ~Item();
 };
 
-// Item class for index files
-class pkgAcqIndex : public pkgAcquire::Item
+/** \brief Information about an index patch (aka diff). */
+struct DiffInfo {
+   /** The filename of the diff. */
+   string file;
+
+   /** The sha1 hash of the diff. */
+   string sha1;
+
+   /** The size of the diff. */
+   unsigned long size;
+};
+
+/** \brief An item that is responsible for fetching an index file of
+ *  package list diffs and starting the package list's download.
+ *
+ *  This item downloads the Index file and parses it, then enqueues
+ *  additional downloads of either the individual patches (using
+ *  pkgAcqIndexDiffs) or the entire Packages file (using pkgAcqIndex).
+ *
+ *  \sa pkgAcqIndexDiffs, pkgAcqIndex
+ */
+class pkgAcqDiffIndex : public pkgAcquire::Item
+{
+ protected:
+   /** \brief If \b true, debugging information will be written to std::clog. */
+   bool Debug;
+
+   /** \brief The item that is currently being downloaded. */
+   pkgAcquire::ItemDesc Desc;
+
+   /** \brief The URI of the index file to recreate at our end (either
+    *  by downloading it or by applying partial patches).
+    */
+   string RealURI;
+
+   /** \brief The MD5Sum that the real index file should have after
+    *  all patches have been applied.
+    */
+   string ExpectedMD5;
+
+   /** \brief The index file which will be patched to generate the new
+    *  file.
+    */
+   string CurrentPackagesFile;
+
+   /** \brief A description of the Packages file (stored in
+    *  pkgAcquire::ItemDesc::Description).
+    */
+   string Description;
+
+ public:
+   // Specialized action members
+   virtual void Failed(string Message,pkgAcquire::MethodConfig *Cnf);
+   virtual void Done(string Message,unsigned long Size,string Md5Hash,
+		     pkgAcquire::MethodConfig *Cnf);
+   virtual string DescURI() {return RealURI + "Index";};
+   virtual string Custom600Headers();
+
+   /** \brief Parse the Index file for a set of Packages diffs.
+    *
+    *  Parses the Index file and creates additional download items as
+    *  necessary.
+    *
+    *  \param IndexDiffFile The name of the Index file.
+    *
+    *  \return \b true if the Index file was successfully parsed, \b
+    *  false otherwise.
+    */
+   bool ParseDiffIndex(string IndexDiffFile);
+   
+
+   /** \brief Create a new pkgAcqDiffIndex.
+    *
+    *  \param Owner The Acquire object that owns this item.
+    *
+    *  \param URI The URI of the list file to download.
+    *
+    *  \param URIDesc A long description of the list file to download.
+    *
+    *  \param ShortDesc A short description of the list file to download.
+    *
+    *  \param ExpectedMD5 The list file's MD5 signature.
+    */
+   pkgAcqDiffIndex(pkgAcquire *Owner,string URI,string URIDesc,
+		   string ShortDesc, string ExpectedMD5);
+};
+
+/** \brief An item that is responsible for fetching all the patches
+ *  that need to be applied to a given package index file.
+ *
+ *  After downloading and applying a single patch, this item will
+ *  enqueue a new pkgAcqIndexDiffs to download and apply the remaining
+ *  patches.  If no patch can be found that applies to an intermediate
+ *  file or if one of the patches cannot be downloaded, falls back to
+ *  downloading the entire package index file using pkgAcqIndex.
+ *
+ *  \sa pkgAcqDiffIndex, pkgAcqIndex
+ */
+class pkgAcqIndexDiffs : public pkgAcquire::Item
 {
+   private:
+
+   /** \brief Queue up the next diff download.
+    *
+    *  Search for the next available diff that applies to the file
+    *  that currently exists on disk, and enqueue it by calling
+    *  QueueURI().
+    *
+    *  \return \b true if an applicable diff was found, \b false
+    *  otherwise.
+    */
+   bool QueueNextDiff();
+
+   /** \brief Handle tasks that must be performed after the item
+    *  finishes downloading.
+    *
+    *  Dequeues the item and checks the resulting file's md5sum
+    *  against ExpectedMD5 after the last patch was applied.
+    *  There is no need to check the md5/sha1 after a "normal" 
+    *  patch because QueueNextDiff() will check the sha1 later.
+    *
+    *  \param allDone If \b true, the file was entirely reconstructed,
+    *  and its md5sum is verified. 
+    */
+   void Finish(bool allDone=false);
+
    protected:
+
+   /** \brief If \b true, debugging output will be written to
+    *  std::clog.
+    */
+   bool Debug;
+
+   /** \brief A description of the item that is currently being
+    *  downloaded.
+    */
+   pkgAcquire::ItemDesc Desc;
+
+   /** \brief The URI of the package index file that is being
+    *  reconstructed.
+    */
+   string RealURI;
+
+   /** \brief The MD5Sum of the package index file that is being
+    *  reconstructed.
+    */
+   string ExpectedMD5;
+
+   /** A description of the file being downloaded. */
+   string Description;
+
+   /** The patches that remain to be downloaded, including the patch
+    *  being downloaded right now.  This list should be ordered so
+    *  that each diff appears before any diff that depends on it.
+    *
+    *  \todo These are indexed by sha1sum; why not use some sort of
+    *  dictionary instead of relying on ordering and stripping them
+    *  off the front?
+    */
+   vector<DiffInfo> available_patches;
+   /** The current status of this patch. */
+   enum DiffState
+     {
+	/** \brief The diff is in an unknown state. */
+	 StateFetchUnkown,
+
+	 /** \brief The diff is currently being fetched. */
+	 StateFetchDiff,
+	 
+	 /** \brief The diff is currently being uncompressed. */
+	 StateUnzipDiff,
+
+	 /** \brief The diff is currently being applied. */
+	 StateApplyDiff
+   } State;
+
+   public:
    
+   /** \brief Called when the patch file failed to be downloaded.
+    *
+    *  This method will fall back to downloading the whole index file
+    *  outright; its arguments are ignored.
+    */
+   virtual void Failed(string Message,pkgAcquire::MethodConfig *Cnf);
+
+   virtual void Done(string Message,unsigned long Size,string Md5Hash,
+		     pkgAcquire::MethodConfig *Cnf);
+   virtual string DescURI() {return RealURI + "Index";};
+
+   /** \brief Create an index diff item.
+    *
+    *  After filling in its basic fields, this invokes Finish(true) if
+    *  #diffs is empty, or QueueNextDiff() otherwise.
+    *
+    *  \param Owner The pkgAcquire object that owns this item.
+    *
+    *  \param URI The URI of the package index file being
+    *  reconstructed.
+    *
+    *  \param URIDesc A long description of this item.
+    *
+    *  \param ShortDesc A brief description of this item.
+    *
+    *  \param ExpectedMD5 The expected md5sum of the completely
+    *  reconstructed package index file; the index file will be tested
+    *  against this value when it is entirely reconstructed.
+    *
+    *  \param diffs The remaining diffs from the index of diffs.  They
+    *  should be ordered so that each diff appears before any diff
+    *  that depends on it.
+    */
+   pkgAcqIndexDiffs(pkgAcquire *Owner,string URI,string URIDesc,
+		    string ShortDesc, string ExpectedMD5,
+		    vector<DiffInfo> diffs=vector<DiffInfo>());
+};
+
+/** \brief An acquire item that is responsible for fetching an index
+ *  file (e.g., Packages or Sources).
+ *
+ *  \sa pkgAcqDiffIndex, pkgAcqIndexDiffs, pkgAcqIndexTrans
+ *
+ *  \todo Why does pkgAcqIndex have protected members?
+ */
+class pkgAcqIndex : public pkgAcquire::Item
+{
+   protected:
+
+   /** \brief If \b true, the index file has been decompressed. */
    bool Decompression;
+
+   /** \brief If \b true, the partially downloaded file will be
+    *  removed when the download completes.
+    */
    bool Erase;
+
+   /** \brief The download request that is currently being
+    *   processed.
+    */
    pkgAcquire::ItemDesc Desc;
+
+   /** \brief The object that is actually being fetched (minus any
+    *  compression-related extensions).
+    */
    string RealURI;
+
+   /** \brief The expected md5sum of the decompressed index file. */
    string ExpectedMD5;
+
+   /** \brief The compression-related file extension that is being
+    *  added to the downloaded file (e.g., ".gz" or ".bz2").
+    */
    string CompressionExtension;
 
    public:
@@ -105,36 +536,120 @@ class pkgAcqIndex : public pkgAcquire::Item
    virtual string Custom600Headers();
    virtual string DescURI() {return RealURI + CompressionExtension;};
 
+   /** \brief Create a pkgAcqIndex.
+    *
+    *  \param Owner The pkgAcquire object with which this item is
+    *  associated.
+    *
+    *  \param URI The URI of the index file that is to be downloaded.
+    *
+    *  \param URIDesc A "URI-style" description of this index file.
+    *
+    *  \param ShortDesc A brief description of this index file.
+    *
+    *  \param ExpectedMD5 The expected md5sum of this index file.
+    *
+    *  \param compressExt The compression-related extension with which
+    *  this index file should be downloaded, or "" to autodetect
+    *  (".bz2" is used if bzip2 is installed, ".gz" otherwise).
+    */
    pkgAcqIndex(pkgAcquire *Owner,string URI,string URIDesc,
 	       string ShortDesct, string ExpectedMD5, string compressExt="");
 };
 
-// Item class for translated package index files
+/** \brief An acquire item that is responsible for fetching a
+ *  translated index file.
+ *
+ *  The only difference from pkgAcqIndex is that transient failures
+ *  are suppressed: no error occurs if the translated index file is
+ *  missing.
+ */
 class pkgAcqIndexTrans : public pkgAcqIndex
 {
    public:
   
    virtual void Failed(string Message,pkgAcquire::MethodConfig *Cnf);
+
+   /** \brief Create a pkgAcqIndexTrans.
+    *
+    *  \param Owner The pkgAcquire object with which this item is
+    *  associated.
+    *
+    *  \param URI The URI of the index file that is to be downloaded.
+    *
+    *  \param URIDesc A "URI-style" description of this index file.
+    *
+    *  \param ShortDesc A brief description of this index file.
+    *
+    *  \param ExpectedMD5 The expected md5sum of this index file.
+    *
+    *  \param compressExt The compression-related extension with which
+    *  this index file should be downloaded, or "" to autodetect
+    *  (".bz2" is used if bzip2 is installed, ".gz" otherwise).
+    */
    pkgAcqIndexTrans(pkgAcquire *Owner,string URI,string URIDesc,
-		    string ShortDesct);
+		    string ShortDesc);
 };
 
+/** \brief Information about an index file. */
 struct IndexTarget
 {
+   /** \brief A URI from which the index file can be downloaded. */
    string URI;
+
+   /** \brief A description of the index file. */
    string Description;
+
+   /** \brief A shorter description of the index file. */
    string ShortDesc;
+
+   /** \brief The key by which this index file should be
+    *  looked up within the meta signature file.
+    */
    string MetaKey;
 };
 
-// Item class for index signatures
+/** \brief An acquire item that downloads the detached signature
+ *  of a meta-index (Release) file, then queues up the release
+ *  file itself.
+ *
+ *  \todo Why protected members?
+ *
+ *  \sa pkgAcqMetaIndex
+ */
 class pkgAcqMetaSig : public pkgAcquire::Item
 {
    protected:
-   
+   /** \brief The fetch request that is currently being processed. */
    pkgAcquire::ItemDesc Desc;
-   string RealURI,MetaIndexURI,MetaIndexURIDesc,MetaIndexShortDesc;
+
+   /** \brief The URI of the signature file.  Unlike Desc.URI, this is
+    *  never modified; it is used to determine the file that is being
+    *  downloaded.
+    */
+   string RealURI;
+
+   /** \brief The URI of the meta-index file to be fetched after the signature. */
+   string MetaIndexURI;
+
+   /** \brief A "URI-style" description of the meta-index file to be
+    *  fetched after the signature.
+    */
+   string MetaIndexURIDesc;
+
+   /** \brief A brief description of the meta-index file to be fetched
+    *  after the signature.
+    */
+   string MetaIndexShortDesc;
+
+   /** \brief A package-system-specific parser for the meta-index file. */
    indexRecords* MetaIndexParser;
+
+   /** \brief The index files which should be looked up in the meta-index
+    *  and then downloaded.
+    *
+    *  \todo Why a list of pointers instead of a list of structs?
+    */
    const vector<struct IndexTarget*>* IndexTargets;
 
    public:
@@ -146,29 +661,90 @@ class pkgAcqMetaSig : public pkgAcquire::Item
    virtual string Custom600Headers();
    virtual string DescURI() {return RealURI; };
 
+   /** \brief Create a new pkgAcqMetaSig. */
    pkgAcqMetaSig(pkgAcquire *Owner,string URI,string URIDesc, string ShortDesc,
 		 string MetaIndexURI, string MetaIndexURIDesc, string MetaIndexShortDesc,
 		 const vector<struct IndexTarget*>* IndexTargets,
 		 indexRecords* MetaIndexParser);
 };
 
-// Item class for index signatures
+/** \brief An item that is responsible for downloading the meta-index
+ *  file (i.e., Release) itself and verifying its signature.
+ *
+ *  Once the download and verification are complete, the downloads of
+ *  the individual index files are queued up using pkgAcqDiffIndex.
+ *  If the meta-index file had a valid signature, the expected md5sums
+ *  of the index files will be the md5sums listed in the meta-index;
+ *  otherwise, the expected md5sums will be "" (causing the
+ *  authentication of the index files to be bypassed).
+ */
 class pkgAcqMetaIndex : public pkgAcquire::Item
 {
    protected:
-   
+   /** \brief The fetch command that is currently being processed. */
    pkgAcquire::ItemDesc Desc;
-   string RealURI; // FIXME: is this redundant w/ Desc.URI?
+
+   /** \brief The URI that is actually being downloaded; never
+    *  modified by pkgAcqMetaIndex.
+    */
+   string RealURI;
+
+   /** \brief The file in which the signature for this index was stored.
+    *
+    *  If empty, the signature and the md5sums of the individual
+    *  indices will not be checked.
+    */
    string SigFile;
+
+   /** \brief The index files to download. */
    const vector<struct IndexTarget*>* IndexTargets;
+
+   /** \brief The parser for the meta-index file. */
    indexRecords* MetaIndexParser;
+
+   /** \brief If \b true, the index's signature is currently being verified.
+    */
    bool AuthPass;
    // required to deal gracefully with problems caused by incorrect ims hits
    bool IMSHit; 
 
+   /** \brief Check that the release file is a release file for the
+    *  correct distribution.
+    *
+    *  \return \b true if no fatal errors were encountered.
+    */
    bool VerifyVendor(string Message);
+
+   /** \brief Called when a file is finished being retrieved.
+    *
+    *  If the file was not downloaded to DestFile, a copy process is
+    *  set up to copy it to DestFile; otherwise, Complete is set to \b
+    *  true and the file is moved to its final location.
+    *
+    *  \param Message The message block received from the fetch
+    *  subprocess.
+    */
    void RetrievalDone(string Message);
+
+   /** \brief Called when authentication succeeded.
+    *
+    *  Sanity-checks the authenticated file, queues up the individual
+    *  index files for download, and saves the signature in the lists
+    *  directory next to the authenticated list file.
+    *
+    *  \param Message The message block received from the fetch
+    *  subprocess.
+    */
    void AuthDone(string Message);
+
+   /** \brief Starts downloading the individual index files.
+    *
+    *  \param verify If \b true, only indices whose expected md5sum
+    *  can be determined from the meta-index will be downloaded, and
+    *  the md5sums of indices will be checked (reporting
+    *  #StatAuthError if there is a mismatch).  If verify is \b false,
+    *  no md5sum checking will be performed.
+    */
    void QueueIndexes(bool verify);
    
    public:
@@ -180,6 +756,7 @@ class pkgAcqMetaIndex : public pkgAcquire::Item
    virtual string Custom600Headers();
    virtual string DescURI() {return RealURI; };
 
+   /** \brief Create a new pkgAcqMetaIndex. */
    pkgAcqMetaIndex(pkgAcquire *Owner,
 		   string URI,string URIDesc, string ShortDesc,
 		   string SigFile,
@@ -187,28 +764,58 @@ class pkgAcqMetaIndex : public pkgAcquire::Item
 		   indexRecords* MetaIndexParser);
 };
 
-// Item class for archive files
+/** \brief An item that is responsible for fetching a package file.
+ *
+ *  If the package file already exists in the cache, nothing will be
+ *  done.
+ */
 class pkgAcqArchive : public pkgAcquire::Item
 {
    protected:
-   
-   // State information for the retry mechanism
+   /** \brief The package version being fetched. */
    pkgCache::VerIterator Version;
+
+   /** \brief The fetch command that is currently being processed. */
    pkgAcquire::ItemDesc Desc;
+
+   /** \brief The list of sources from which to pick archives to
+    *  download this package from.
+    */
    pkgSourceList *Sources;
+
+   /** \brief A package records object, used to look up the file
+    *  corresponding to each version of the package.
+    */
    pkgRecords *Recs;
+
+   /** \brief The md5sum of this package. */
    string MD5;
+
+   /** \brief A location in which the actual filename of the package
+    *  should be stored.
+    */
    string &StoreFilename;
+
+   /** \brief The next file for this version to try to download. */
    pkgCache::VerFileIterator Vf;
+
+   /** \brief How many (more) times to try to find a new source from
+    *  which to download this package version if it fails.
+    *
+    *  Set from Acquire::Retries.
+    */
    unsigned int Retries;
+
+   /** \brief \b true if this version file is being downloaded from a
+    *  trusted source.
+    */
    bool Trusted; 
 
-   // Queue the next available file for download.
+   /** \brief Queue up the next available file for this version. */
    bool QueueNext();
    
    public:
    
-   // Specialized action members
    virtual void Failed(string Message,pkgAcquire::MethodConfig *Cnf);
    virtual void Done(string Message,unsigned long Size,string Md5Hash,
 		     pkgAcquire::MethodConfig *Cnf);
@@ -216,18 +823,49 @@ class pkgAcqArchive : public pkgAcquire::Item
    virtual string DescURI() {return Desc.URI;};
    virtual string ShortDesc() {return Desc.ShortDesc;};
    virtual void Finished();
+
    virtual bool IsTrusted();
    
+   /** \brief Create a new pkgAcqArchive.
+    *
+    *  \param Owner The pkgAcquire object with which this item is
+    *  associated.
+    *
+    *  \param Sources The sources from which to download version
+    *  files.
+    *
+    *  \param Recs A package records object, used to look up the file
+    *  corresponding to each version of the package.
+    *
+    *  \param Version The package version to download.
+    *
+    *  \param StoreFilename A location in which the actual filename of
+    *  the package should be stored.  It will be set to a guessed
+    *  basename in the constructor, and filled in with a fully
+    *  qualified filename once the download finishes.
+    */
    pkgAcqArchive(pkgAcquire *Owner,pkgSourceList *Sources,
 		 pkgRecords *Recs,pkgCache::VerIterator const &Version,
 		 string &StoreFilename);
 };
 
-// Fetch a generic file to the current directory
+/** \brief Retrieve an arbitrary file to the current directory.
+ *
+ *  The file is retrieved even if it is accessed via a URL type that
+ *  normally is a NOP, such as "file".  If the download fails, the
+ *  partial file is renamed to get a ".FAILED" extension.
+ */
 class pkgAcqFile : public pkgAcquire::Item
 {
+   /** \brief The currently active download process. */
    pkgAcquire::ItemDesc Desc;
+
+   /** \brief The md5sum of the file to download, if it is known. */
    string Md5Hash;
+
+   /** \brief How many times to retry the download, set from
+    *  Acquire::Retries.
+    */
    unsigned int Retries;
    
    public:
@@ -239,13 +877,40 @@ class pkgAcqFile : public pkgAcquire::Item
    virtual string MD5Sum() {return Md5Hash;};
    virtual string DescURI() {return Desc.URI;};
 
-   // If DestFilename is empty, download to DestDir/<basename> if
-   // DestDir is non-empty, $CWD/<basename> otherwise.  If
-   // DestFilename is NOT empty, DestDir is ignored and DestFilename
-   // is the absolute name to which the file should be downloaded.
+   /** \brief Create a new pkgAcqFile object.
+    *
+    *  \param Owner The pkgAcquire object with which this object is
+    *  associated.
+    *
+    *  \param URI The URI to download.
+    *
+    *  \param MD5 The md5sum of the file to download, if it is known;
+    *  otherwise "".
+    *
+    *  \param Size The size of the file to download, if it is known;
+    *  otherwise 0.
+    *
+    *  \param Desc A description of the file being downloaded.
+    *
+    *  \param ShortDesc A brief description of the file being
+    *  downloaded.
+    *
+    *  \param DestDir The directory the file should be downloaded into.
+    *
+    *  \param DestFilename The filename+path the file is downloaded to.
+    *
+    *
+    * If DestFilename is empty, download to DestDir/<basename> if
+    * DestDir is non-empty, $CWD/<basename> otherwise.  If
+    * DestFilename is NOT empty, DestDir is ignored and DestFilename
+    * is the absolute name to which the file should be downloaded.
+    */
+
    pkgAcqFile(pkgAcquire *Owner, string URI, string MD5, unsigned long Size,
 	      string Desc, string ShortDesc,
 	      const string &DestDir="", const string &DestFilename="");
 };
 
+/** @} */
+
 #endif