Query(): Fix _nmlib -> nmlib type & clarify docs a bit

[notmuch] / cnotmuch / database.py

diff --git a/cnotmuch/database.py b/cnotmuch/database.py
index 2b51e5ea34a9fd0a0291f3eac57b3b6260c704fd..6a118bdfe78b8d5fa134dbfc43c1f9b1253318ae 100644 (file)
--- a/cnotmuch/database.py
+++ b/cnotmuch/database.py
@@ -1,5 +1,5 @@
-import ctypes
-from ctypes import c_int, c_char_p, c_void_p, c_uint64
+import ctypes, os
+from ctypes import c_int, c_char_p, c_void_p, c_uint, c_uint64, c_bool

 from cnotmuch.globals import nmlib, STATUS, NotmuchError, Enum
 import logging
 from datetime import date
 from cnotmuch.globals import nmlib, STATUS, NotmuchError, Enum
 import logging
 from datetime import date


@@ -13,16 +13,20 @@ class Database(object):
            as well. Accessing these objects will lead to segfaults and
            other unexpected behavior. See above for more details.
     """
            as well. Accessing these objects will lead to segfaults and
            other unexpected behavior. See above for more details.
     """

-    MODE = Enum(['READ_ONLY','READ_WRITE'])
-    """Constants: Mode in which to open the database"""
-

     _std_db_path = None
     """Class attribute to cache user's default database"""
 
     _std_db_path = None
     """Class attribute to cache user's default database"""
 

+    MODE = Enum(['READ_ONLY','READ_WRITE'])
+    """Constants: Mode in which to open the database"""
+

     """notmuch_database_get_path (notmuch_database_t *database)"""
     _get_path = nmlib.notmuch_database_get_path
     _get_path.restype = c_char_p
 
     """notmuch_database_get_path (notmuch_database_t *database)"""
     _get_path = nmlib.notmuch_database_get_path
     _get_path.restype = c_char_p
 

+    """notmuch_database_get_version"""
+    _get_version = nmlib.notmuch_database_get_version
+    _get_version.restype = c_uint
+

     """notmuch_database_open (const char *path, notmuch_database_mode_t mode)"""
     _open = nmlib.notmuch_database_open 
     _open.restype = c_void_p
     """notmuch_database_open (const char *path, notmuch_database_mode_t mode)"""
     _open = nmlib.notmuch_database_open 
     _open.restype = c_void_p


@@ -39,19 +43,22 @@ class Database(object):
     _create = nmlib.notmuch_database_create
     _create.restype = c_void_p
 
     _create = nmlib.notmuch_database_create
     _create.restype = c_void_p
 

-    def __init__(self, path=None, create=False, mode= MODE.READ_ONLY):
-        """If *path* is *None*, we will try to read a users notmuch
-        configuration and use his default database. If *create* is `True`,
-        the database will always be created in
-        :attr:`MODE`.READ_WRITE mode.
+    def __init__(self, path=None, create=False, mode= 0):
+        """If *path* is *None*, we will try to read a users notmuch 
+        configuration and use his configured database. The location of the 
+        configuration file can be specified through the environment variable
+        *NOTMUCH_CONFIG*, falling back to the default `~/.notmuch-config`.
+
+        If *create* is `True`, the database will always be created in
+        :attr:`MODE`.READ_WRITE mode. Default mode for opening is READ_ONLY.

 
         :param path:   Directory to open/create the database in (see
                        above for behavior if `None`)
         :type path:    `str` or `None`
 
         :param path:   Directory to open/create the database in (see
                        above for behavior if `None`)
         :type path:    `str` or `None`

-        :param create: False to open an existing, True to create a new
+        :param create: Pass `False` to open an existing, `True` to create a new

                        database.  
         :type create:  bool
                        database.  
         :type create:  bool

-        :param mode:   Mode to open a database in. Always 
+        :param mode:   Mode to open a database in. Is always 

                        :attr:`MODE`.READ_WRITE when creating a new one.
         :type mode:    :attr:`MODE`
         :returns:      Nothing
                        :attr:`MODE`.READ_WRITE when creating a new one.
         :type mode:    :attr:`MODE`
         :returns:      Nothing


@@ -73,7 +80,7 @@ class Database(object):
     def create(self, path):
         """Creates a new notmuch database
 
     def create(self, path):
         """Creates a new notmuch database
 

-        This function is used by __init__() usually does not need
+        This function is used by __init__() and usually does not need

         to be called directly. It wraps the underlying
         *notmuch_database_create* function and creates a new notmuch
         database at *path*. It will always return a database in
         to be called directly. It wraps the underlying
         *notmuch_database_create* function and creates a new notmuch
         database at *path*. It will always return a database in


@@ -90,24 +97,24 @@ class Database(object):
             raise NotmuchError(
             message="Cannot create db, this Database() already has an open one.")
 
             raise NotmuchError(
             message="Cannot create db, this Database() already has an open one.")
 

-        res = Database._create(path, MODE.READ_WRITE)
+        res = Database._create(path, Database.MODE.READ_WRITE)

 
         if res is None:
             raise NotmuchError(
                 message="Could not create the specified database")
         self._db = res
 
 
         if res is None:
             raise NotmuchError(
                 message="Could not create the specified database")
         self._db = res
 

-    def open(self, path, mode= MODE.READ_ONLY): 
+    def open(self, path, mode= 0): 

         """Opens an existing database
 
         """Opens an existing database
 

-        This function is used by __init__() usually does not need
+        This function is used by __init__() and usually does not need

         to be called directly. It wraps the underlying
         *notmuch_database_open* function.
 
         :param status: Open the database in read-only or read-write mode
         :type status:  :attr:`MODE` 
         :returns: Nothing
         to be called directly. It wraps the underlying
         *notmuch_database_open* function.
 
         :param status: Open the database in read-only or read-write mode
         :type status:  :attr:`MODE` 
         :returns: Nothing

-        :exception: Raises :exc:`notmuch.NotmuchError` in case
+        :exception: Raises :exc:`NotmuchError` in case

                     of any failure (after printing an error message on stderr).
         """
 
                     of any failure (after printing an error message on stderr).
         """
 


@@ -124,12 +131,41 @@ class Database(object):
         Wraps notmuch_database_get_path"""
         return Database._get_path(self._db)
 
         Wraps notmuch_database_get_path"""
         return Database._get_path(self._db)
 

+    def get_version(self):
+        """Returns the database format version
+
+        :returns: The database version as positive integer
+        :exception: :exc:`NotmuchError` with STATUS.NOT_INITIALIZED if
+                    the database was not intitialized.
+        """
+        if self._db is None:
+            raise NotmuchError(STATUS.NOT_INITIALIZED)
+
+        return Database._get_version (self._db)
+
+    def needs_upgrade(self):
+        """Does this database need to be upgraded before writing to it?
+
+        If this function returns True then no functions that modify the
+        database (:meth:`add_message`, :meth:`add_tag`,
+        :meth:`Directory.set_mtime`, etc.) will work unless :meth:`upgrade` 
+        is called successfully first.
+
+        :returns: `True` or `False`
+        :exception: :exc:`NotmuchError` with STATUS.NOT_INITIALIZED if
+                    the database was not intitialized.
+        """
+        if self._db is None:
+            raise NotmuchError(STATUS.NOT_INITIALIZED)
+
+        return notmuch_database_needs_upgrade(self.db) 
+

     def find_message(self, msgid):
         """Returns a :class:`Message` as identified by its message ID
 
     def find_message(self, msgid):
         """Returns a :class:`Message` as identified by its message ID
 

-        wraps *notmuch_database_find_message*
+        Wraps the underlying *notmuch_database_find_message* function.

 
 

-        :param msgid: The message id
+        :param msgid: The message ID

         :type msgid: string
         :returns: :class:`Message` or `None` if no message is found or if an
                   out-of-memory situation occurs.
         :type msgid: string
         :returns: :class:`Message` or `None` if no message is found or if an
                   out-of-memory situation occurs.


@@ -146,8 +182,8 @@ class Database(object):
     def get_all_tags(self):
         """Returns :class:`Tags` with a list of all tags found in the database
 
     def get_all_tags(self):
         """Returns :class:`Tags` with a list of all tags found in the database
 

-        :returns: :class:`Tags` object or raises :exc:`NotmuchError` with 
-                  STATUS.NULL_POINTER on error
+        :returns: :class:`Tags`
+        :execption: :exc:`NotmuchError` with STATUS.NULL_POINTER on error

         """
         if self._db is None:
             raise NotmuchError(STATUS.NOT_INITIALIZED)
         """
         if self._db is None:
             raise NotmuchError(STATUS.NOT_INITIALIZED)


@@ -171,9 +207,10 @@ class Database(object):
 
         Throws a NotmuchError if it cannot find it"""
         from ConfigParser import SafeConfigParser
 
         Throws a NotmuchError if it cannot find it"""
         from ConfigParser import SafeConfigParser

-        import os.path

         config = SafeConfigParser()
         config = SafeConfigParser()

-        config.read(os.path.expanduser('~/.notmuch-config'))
+        conf_f = os.getenv('NOTMUCH_CONFIG',
+                           os.path.expanduser('~/.notmuch-config'))
+        config.read(conf_f)

         if not config.has_option('database','path'):
             raise NotmuchError(message=
                                "No DB path specified and no user default found")
         if not config.has_option('database','path'):
             raise NotmuchError(message=
                                "No DB path specified and no user default found")


@@ -181,22 +218,29 @@ class Database(object):
 
     @property
     def db_p(self):
 
     @property
     def db_p(self):

-        """Property returning a pointer to the notmuch_database_t or `None`.
+        """Property returning a pointer to the notmuch_database_t or `None`

 
         This should normally not be needed by a user."""
         return self._db
 
 #------------------------------------------------------------------------------
 class Query(object):
 
         This should normally not be needed by a user."""
         return self._db
 
 #------------------------------------------------------------------------------
 class Query(object):

-    """ Wrapper around a notmuch_query_t
+    """ Represents a search query on an opened :class:`Database`.
+
+    A query selects and filters a subset of messages from the notmuch
+    database we derive from.

 
 

-    Do note that as soon as we tear down this object, all derived
-    threads, and messages will be freed as well.
+    Technically, it wraps the underlying *notmuch_query_t* struct.
+
+    .. note:: Do remember that as soon as we tear down this object,
+           all underlying derived objects such as threads,
+           messages, tags etc will be freed by the underlying library
+           as well. Accessing these objects will lead to segfaults and
+           other unexpected behavior. See above for more details.

     """
     # constants
     """
     # constants

-    SORT_OLDEST_FIRST = 0
-    SORT_NEWEST_FIRST = 1
-    SORT_MESSAGE_ID = 2
+    SORT = Enum(['OLDEST_FIRST','NEWEST_FIRST','MESSAGE_ID'])
+    """Constants: Sort order in which to return results"""

 
     """notmuch_query_create"""
     _create = nmlib.notmuch_query_create
 
     """notmuch_query_create"""
     _create = nmlib.notmuch_query_create


@@ -206,17 +250,38 @@ class Query(object):
     _search_messages = nmlib.notmuch_query_search_messages
     _search_messages.restype = c_void_p
 
     _search_messages = nmlib.notmuch_query_search_messages
     _search_messages.restype = c_void_p
 

+
+    """notmuch_query_count_messages"""
+    _count_messages = nmlib.notmuch_query_count_messages
+    _count_messages.restype = c_uint
+

     def __init__(self, db, querystr):
     def __init__(self, db, querystr):

-        """TODO: document"""
+        """
+        :param db: An open database which we derive the Query from.
+        :type db: :class:`Database`
+        :param querystr: The query string for the message.
+        :type querystr: str
+        """

         self._db = None
         self._query = None
         self.create(db, querystr)
 
     def create(self, db, querystr):
         self._db = None
         self._query = None
         self.create(db, querystr)
 
     def create(self, db, querystr):

-        """db is a Database() and querystr a string
+        """Creates a new query derived from a Database.
+
+        This function is utilized by __init__() and usually does not need to 
+        be called directly.
+
+        :param db: Database to create the query from.
+        :type db: :class:`Database`
+        :param querystr: The query string
+        :type querystr: str
+        :returns: Nothing
+        :exception: :exc:`NotmuchError`

 
 

-        raises NotmuchError STATUS.NOT_INITIALIZED if db is not inited and
-        STATUS.NULL_POINTER if the query creation failed (too little memory)
+                      * STATUS.NOT_INITIALIZED if db is not inited
+                      * STATUS.NULL_POINTER if the query creation failed 
+                        (too little memory)

         """
         if db.db_p is None:
             raise NotmuchError(STATUS.NOT_INITIALIZED)            
         """
         if db.db_p is None:
             raise NotmuchError(STATUS.NOT_INITIALIZED)            


@@ -230,10 +295,14 @@ class Query(object):
         self._query = query_p
 
     def set_sort(self, sort):
         self._query = query_p
 
     def set_sort(self, sort):

-        """notmuch_query_set_sort
+        """Set the sort order future results will be delivered in

 
 

-        :param sort: one of Query.SORT_OLDEST_FIRST|SORT_NEWEST_FIRST|SORT_MESSAGE_ID
-        :returns: Nothing, but raises NotmuchError if query is not inited
+        Wraps the underlying *notmuch_query_set_sort* function.
+
+        :param sort: Sort order (see :attr:`Query.SORT`)
+        :returns: Nothing
+        :exception: :exc:`NotmuchError` STATUS.NOT_INITIALIZED if query has not 
+                    been initialized.

         """
         if self._query is None:
             raise NotmuchError(STATUS.NOT_INITIALIZED)
         """
         if self._query is None:
             raise NotmuchError(STATUS.NOT_INITIALIZED)


@@ -241,8 +310,17 @@ class Query(object):
         nmlib.notmuch_query_set_sort(self._query, sort)
 
     def search_messages(self):
         nmlib.notmuch_query_set_sort(self._query, sort)
 
     def search_messages(self):

-        """notmuch_query_search_messages
-        Returns Messages() or a raises a NotmuchError()
+        """Filter messages according to the query and return
+        :class:`Messages` in the defined sort order
+
+        Technically, it wraps the underlying
+        *notmuch_query_search_messages* function.
+
+        :returns: :class:`Messages`
+        :exception: :exc:`NotmuchError`
+
+                      * STATUS.NOT_INITIALIZED if query is not inited
+                      * STATUS.NULL_POINTER if search_messages failed 

         """
         if self._query is None:
             raise NotmuchError(STATUS.NOT_INITIALIZED)            
         """
         if self._query is None:
             raise NotmuchError(STATUS.NOT_INITIALIZED)            


@@ -254,6 +332,25 @@ class Query(object):
 
         return Messages(msgs_p,self)
 
 
         return Messages(msgs_p,self)
 

+    def count_messages(self):
+        """Estimate the number of messages matching the query
+
+        This function performs a search and returns Xapian's best
+        guess as to the number of matching messages. It is much faster
+        than performing :meth:`search_messages` and counting the
+        result with `len()` (although it always returned the same
+        result in my tests). Technically, it wraps the underlying
+        *notmuch_query_count_messages* function.
+
+        :returns: :class:`Messages`
+        :exception: :exc:`NotmuchError`
+
+                      * STATUS.NOT_INITIALIZED if query is not inited
+        """
+        if self._query is None:
+            raise NotmuchError(STATUS.NOT_INITIALIZED)            
+
+        return Query._count_messages(self._query)

 
     def __del__(self):
         """Close and free the Query"""
 
     def __del__(self):
         """Close and free the Query"""


@@ -263,7 +360,30 @@ class Query(object):
 
 #------------------------------------------------------------------------------
 class Tags(object):
 
 #------------------------------------------------------------------------------
 class Tags(object):

-    """Wrapper around notmuch_tags_t"""
+    """Represents a list of notmuch tags
+
+    This object provides an iterator over a list of notmuch tags. Do
+    note that the underlying library only provides a one-time iterator
+    (it cannot reset the iterator to the start). Thus iterating over
+    the function will "exhaust" the list of tags, and a subsequent
+    iteration attempt will raise a :exc:`NotmuchError`
+    STATUS.NOT_INITIALIZED. Also note, that any function that uses
+    iteration (nearly all) will also exhaust the tags. So both::
+
+      for tag in tags: print tag 
+
+    as well as::
+
+       number_of_tags = len(tags)
+
+    and even a simple::
+
+       #str() iterates over all tags to construct a space separated list
+       print(str(tags))
+
+    will "exhaust" the Tags. If you need to re-iterate over a list of
+    tags you will need to retrieve a new :class:`Tags` object.
+    """

 
     #notmuch_tags_get
     _get = nmlib.notmuch_tags_get
 
     #notmuch_tags_get
     _get = nmlib.notmuch_tags_get


@@ -271,18 +391,20 @@ class Tags(object):
 
     def __init__(self, tags_p, parent=None):
         """
 
     def __init__(self, tags_p, parent=None):
         """

-        msg_p is a pointer to an notmuch_message_t Structure. If it is None,
-        we will raise an NotmuchError(STATUS.NULL_POINTER).
-
-        Is passed the parent these tags are derived from, and saves a
-        reference to it, so we can automatically delete the db object
-        once all derived objects are dead.
-
-        Tags() provides an iterator over all contained tags. However, you will
-        only be able to iterate over the Tags once, because the underlying C
-        function only allows iterating once.
-        #TODO: make the iterator work more than once and cache the tags in 
-               the Python object.
+        :param tags_p: A pointer to an underlying *notmuch_tags_t*
+             structure. These are not publically exposed, so a user
+             will almost never instantiate a :class:`Tags` object
+             herself. They are usually handed back as a result,
+             e.g. in :meth:`Database.get_all_tags`.  *tags_p* must be
+             valid, we will raise an :exc:`NotmuchError`
+             (STATUS.NULL_POINTER) if it is `None`.
+        :type tags_p: :class:`ctypes.c_void_p`
+        :param parent: The parent object (ie :class:`Database` or 
+             :class:`Message` these tags are derived from, and saves a
+             reference to it, so we can automatically delete the db object
+             once all derived objects are dead.
+        :TODO: Make the iterator optionally work more than once by
+               cache the tags in the Python object(?)

         """
         if tags_p is None:
             NotmuchError(STATUS.NULL_POINTER)
         """
         if tags_p is None:
             NotmuchError(STATUS.NULL_POINTER)


@@ -308,10 +430,33 @@ class Tags(object):
         nmlib.notmuch_tags_move_to_next(self._tags)
         return tag
 
         nmlib.notmuch_tags_move_to_next(self._tags)
         return tag
 

+    def __len__(self):
+        """len(:class:`Tags`) returns the number of contained tags
+
+        .. note:: As this iterates over the tags, we will not be able
+               to iterate over them again (as in retrieve them)! If
+               the tags have been exhausted already, this will raise a
+               :exc:`NotmuchError` STATUS.NOT_INITIALIZED on
+               subsequent attempts.
+        """
+        if self._tags is None:
+            raise NotmuchError(STATUS.NOT_INITIALIZED)
+
+        i=0
+        while nmlib.notmuch_tags_valid(self._msgs):
+            nmlib.notmuch_tags_move_to_next(self._msgs)
+            i += 1
+        self._tags = None
+        return i
+

     def __str__(self):
     def __str__(self):

-        """str() of Tags() is a space separated list of tags
+        """The str() representation of Tags() is a space separated list of tags

 
 

-        This iterates over the list of Tags and will therefore 'exhaust' Tags()
+        .. note:: As this iterates over the tags, we will not be able
+               to iterate over them again (as in retrieve them)! If
+               the tags have been exhausted already, this will raise a
+               :exc:`NotmuchError` STATUS.NOT_INITIALIZED on
+               subsequent attempts.

         """
         return " ".join(self)
 
         """
         return " ".join(self)
 


@@ -324,7 +469,52 @@ class Tags(object):
 
 #------------------------------------------------------------------------------
 class Messages(object):
 
 #------------------------------------------------------------------------------
 class Messages(object):

-    """Wrapper around notmuch_messages_t"""
+    """Represents a list of notmuch messages
+
+    This object provides an iterator over a list of notmuch messages
+    (Technically, it provides a wrapper for the underlying
+    *notmuch_messages_t* structure). Do note that the underlying
+    library only provides a one-time iterator (it cannot reset the
+    iterator to the start). Thus iterating over the function will
+    "exhaust" the list of messages, and a subsequent iteration attempt
+    will raise a :exc:`NotmuchError` STATUS.NOT_INITIALIZED. Also
+    note, that any function that uses iteration will also
+    exhaust the messages. So both::
+
+      for msg in msgs: print msg 
+
+    as well as::
+
+       number_of_msgs = len(msgs)
+
+    will "exhaust" the Messages. If you need to re-iterate over a list of
+    messages you will need to retrieve a new :class:`Messages` object.
+
+    Things are not as bad as it seems though, you can store and reuse
+    the single Message objects as often as you want as long as you
+    keep the parent Messages object around. (Recall that due to
+    hierarchical memory allocation, all derived Message objects will
+    be invalid when we delete the parent Messages() object, even if it
+    was already "exhausted".) So this works::
+
+      db   = Database()
+      msgs = Query(db,'').search_messages() #get a Messages() object
+      msglist = []
+      for m in msgs:
+         msglist.append(m)
+
+      # msgs is "exhausted" now and even len(msgs) will raise an exception.
+      # However it will be kept around until all retrieved Message() objects are
+      # also deleted. If you did e.g. an explicit del(msgs) here, the 
+      # following lines would fail.
+      
+      # You can reiterate over *msglist* however as often as you want. 
+      # It is simply a list with Message objects.
+
+      print (msglist[0].get_filename())
+      print (msglist[1].get_filename())
+      print (msglist[0].get_message_id())
+    """

 
     #notmuch_tags_get
     _get = nmlib.notmuch_messages_get
 
     #notmuch_tags_get
     _get = nmlib.notmuch_messages_get


@@ -335,18 +525,20 @@ class Messages(object):
 
     def __init__(self, msgs_p, parent=None):
         """
 
     def __init__(self, msgs_p, parent=None):
         """

-        msg_p is a pointer to an notmuch_messages_t Structure. If it is None,
-        we will raise an NotmuchError(STATUS.NULL_POINTER).
-
-        If passed the parent query this Messages() is derived from, it saves a
-        reference to it, so we can automatically delete the parent query object
-        once all derived objects are dead.
-
-        Messages() provides an iterator over all contained Message()s.
-        However, you will only be able to iterate over it once,
-        because the underlying C function only allows iterating once.
-        #TODO: make the iterator work more than once and cache the tags in 
-               the Python object.
+        :param msgs_p:  A pointer to an underlying *notmuch_messages_t*
+             structure. These are not publically exposed, so a user
+             will almost never instantiate a :class:`Messages` object
+             herself. They are usually handed back as a result,
+             e.g. in :meth:`Query.search_messages`.  *msgs_p* must be
+             valid, we will raise an :exc:`NotmuchError`
+             (STATUS.NULL_POINTER) if it is `None`.
+        :type msgs_p: :class:`ctypes.c_void_p`
+        :param parent: The parent object
+             (ie :class:`Query`) these tags are derived from. It saves
+             a reference to it, so we can automatically delete the db
+             object once all derived objects are dead.
+        :TODO: Make the iterator work more than once and cache the tags in 
+               the Python object.(?)

         """
         if msgs_p is None:
             NotmuchError(STATUS.NULL_POINTER)
         """
         if msgs_p is None:
             NotmuchError(STATUS.NULL_POINTER)


@@ -357,11 +549,13 @@ class Messages(object):
         logging.debug("Inited Messages derived from %s" %(str(parent)))
 
     def collect_tags(self):
         logging.debug("Inited Messages derived from %s" %(str(parent)))
 
     def collect_tags(self):

-        """ return the Tags() belonging to the messages
-        
-        Do note that collect_tags will iterate over the messages and
-        therefore will not allow further iterationsl
-        Raises NotmuchError(STATUS.NOT_INITIALIZED) if not inited
+        """Return the unique :class:`Tags` in the contained messages
+
+        :returns: :class:`Tags`
+        :exceptions: :exc:`NotmuchError` STATUS.NOT_INITIALIZED if not inited
+
+        .. note:: :meth:`collect_tags` will iterate over the messages and
+          therefore will not allow further iterations.

         """
         if self._msgs is None:
             raise NotmuchError(STATUS.NOT_INITIALIZED)
         """
         if self._msgs is None:
             raise NotmuchError(STATUS.NOT_INITIALIZED)


@@ -392,9 +586,9 @@ class Messages(object):
         return msg
 
     def __len__(self):
         return msg
 
     def __len__(self):

-        """ Returns the number of contained messages
+        """len(:class:`Messages`) returns the number of contained messages

 
 

-        :note: As this iterates over the messages, we will not be able to 
+        .. note:: As this iterates over the messages, we will not be able to 

                iterate over them again (as in retrieve them)!
         """
         if self._msgs is None:
                iterate over them again (as in retrieve them)!
         """
         if self._msgs is None:


@@ -418,7 +612,10 @@ class Messages(object):
 
 #------------------------------------------------------------------------------
 class Message(object):
 
 #------------------------------------------------------------------------------
 class Message(object):

-    """Wrapper around notmuch_message_t"""
+    """Represents a single Email message
+
+    Technically, this wraps the underlying *notmuch_message_t* structure.
+    """

 
     """notmuch_message_get_filename (notmuch_message_t *message)"""
     _get_filename = nmlib.notmuch_message_get_filename
 
     """notmuch_message_get_filename (notmuch_message_t *message)"""
     _get_filename = nmlib.notmuch_message_get_filename


@@ -439,12 +636,13 @@ class Message(object):
 
     def __init__(self, msg_p, parent=None):
         """
 
     def __init__(self, msg_p, parent=None):
         """

-        msg_p is a pointer to an notmuch_message_t Structure. If it is None,
-        we will raise an NotmuchError(STATUS.NULL_POINTER).
-
-        Is a 'parent' object is passed which this message is derived from,
-        we save a reference to it, so we can automatically delete the parent
-        object once all derived objects are dead.
+        :param msg_p: A pointer to an internal notmuch_message_t
+            Structure.  If it is `None`, we will raise an :exc:`NotmuchError`
+            STATUS.NULL_POINTER.
+        :param parent: A 'parent' object is passed which this message is
+              derived from. We save a reference to it, so we can
+              automatically delete the parent object once all derived
+              objects are dead.

         """
         if msg_p is None:
             NotmuchError(STATUS.NULL_POINTER)
         """
         if msg_p is None:
             NotmuchError(STATUS.NULL_POINTER)


@@ -455,28 +653,50 @@ class Message(object):
 
 
     def get_message_id(self):
 
 
     def get_message_id(self):

-        """ return the msg id
+        """Return the message ID

         
         

-        Raises NotmuchError(STATUS.NOT_INITIALIZED) if not inited
+        :returns: String with a message ID
+        :exception: :exc:`NotmuchError` STATUS.NOT_INITIALIZED if the message 
+                    is not initialized.

         """
         if self._msg is None:
             raise NotmuchError(STATUS.NOT_INITIALIZED)
         return Message._get_message_id(self._msg)
 
     def get_date(self):
         """
         if self._msg is None:
             raise NotmuchError(STATUS.NOT_INITIALIZED)
         return Message._get_message_id(self._msg)
 
     def get_date(self):

-        """returns time_t of the message date
+        """Returns time_t of the message date

 
         For the original textual representation of the Date header from the
         message call notmuch_message_get_header() with a header value of
         "date".
 
         For the original textual representation of the Date header from the
         message call notmuch_message_get_header() with a header value of
         "date".

-        Raises NotmuchError(STATUS.NOT_INITIALIZED) if not inited
+
+        :returns: a time_t timestamp
+        :rtype: c_unit64
+        :exception: :exc:`NotmuchError` STATUS.NOT_INITIALIZED if the message 
+                    is not initialized.

         """
         if self._msg is None:
             raise NotmuchError(STATUS.NOT_INITIALIZED)
         return Message._get_date(self._msg)
 
     def get_header(self, header):
         """
         if self._msg is None:
             raise NotmuchError(STATUS.NOT_INITIALIZED)
         return Message._get_date(self._msg)
 
     def get_header(self, header):

-        """ TODO document me"""
+        """Returns a message header
+        
+        This returns any message header that is stored in the notmuch database.
+        This is only a selected subset of headers, which is currently:
+
+          TODO: add stored headers
+
+        :param header: The name of the header to be retrieved.
+                       It is not case-sensitive (TODO: confirm).
+        :type header: str
+        :returns: The header value as string
+        :exception: :exc:`NotmuchError`
+
+                    * STATUS.NOT_INITIALIZED if the message 
+                      is not initialized.
+                    * STATUS.NULL_POINTER, if no header was found
+        """

         if self._msg is None:
             raise NotmuchError(STATUS.NOT_INITIALIZED)
 
         if self._msg is None:
             raise NotmuchError(STATUS.NOT_INITIALIZED)
 


@@ -487,19 +707,26 @@ class Message(object):
         return header
 
     def get_filename(self):
         return header
 
     def get_filename(self):

-        """ return the msg filename
-        
-        Raises NotmuchError(STATUS.NOT_INITIALIZED) if not inited
+        """Return the file path of the message file
+
+        :returns: Absolute file path & name of the message file
+        :exception: :exc:`NotmuchError` STATUS.NOT_INITIALIZED if the message 
+              is not initialized.

         """
         if self._msg is None:
             raise NotmuchError(STATUS.NOT_INITIALIZED)
         return Message._get_filename(self._msg)
 
     def get_tags(self):
         """
         if self._msg is None:
             raise NotmuchError(STATUS.NOT_INITIALIZED)
         return Message._get_filename(self._msg)
 
     def get_tags(self):

-        """ return the msg tags
-        
-        Raises NotmuchError(STATUS.NOT_INITIALIZED) if not inited
-        Raises NotmuchError(STATUS.NULL_POINTER) on error.
+        """ Return the message tags
+
+        :returns: Message tags
+        :rtype: :class:`Tags`
+        :exception: :exc:`NotmuchError`
+
+                      * STATUS.NOT_INITIALIZED if the message 
+                        is not initialized.
+                      * STATUS.NULL_POINTER, on error

         """
         if self._msg is None:
             raise NotmuchError(STATUS.NOT_INITIALIZED)
         """
         if self._msg is None:
             raise NotmuchError(STATUS.NOT_INITIALIZED)


@@ -509,6 +736,187 @@ class Message(object):
             raise NotmuchError(STATUS.NULL_POINTER)
         return Tags(tags_p, self)
 
             raise NotmuchError(STATUS.NULL_POINTER)
         return Tags(tags_p, self)
 

+    def add_tag(self, tag):
+        """Add a tag to the given message
+
+        Adds a tag to the current message. The maximal tag length is defined in
+        the notmuch library and is currently 200 bytes.
+
+        :param tag: String with a 'tag' to be added.
+        :returns: STATUS.SUCCESS if the tag was successfully added.
+                  Raises an exception otherwise.
+        :exception: :exc:`NotmuchError`. They have the following meaning:
+
+                  STATUS.NULL_POINTER
+                    The 'tag' argument is NULL
+                  STATUS.TAG_TOO_LONG
+                    The length of 'tag' is too long 
+                    (exceeds Message.NOTMUCH_TAG_MAX)
+                  STATUS.READ_ONLY_DATABASE
+                    Database was opened in read-only mode so message cannot be 
+                    modified.
+                  STATUS.NOT_INITIALIZED
+                     The message has not been initialized.
+       """
+        if self._msg is None:
+            raise NotmuchError(STATUS.NOT_INITIALIZED)
+
+        status = nmlib.notmuch_message_add_tag (self._msg, tag)
+
+        if STATUS.SUCCESS == status:
+            # return on success
+            return status
+
+        raise NotmuchError(status)
+
+    def remove_tag(self, tag):
+        """Removes a tag from the given message
+
+        If the message has no such tag, this is a non-operation and
+        will report success anyway.
+
+        :param tag: String with a 'tag' to be removed.
+        :returns: STATUS.SUCCESS if the tag was successfully removed or if 
+                  the message had no such tag.
+                  Raises an exception otherwise.
+        :exception: :exc:`NotmuchError`. They have the following meaning:
+
+                   STATUS.NULL_POINTER
+                     The 'tag' argument is NULL
+                   STATUS.TAG_TOO_LONG
+                     The length of 'tag' is too long
+                     (exceeds NOTMUCH_TAG_MAX)
+                   STATUS.READ_ONLY_DATABASE
+                     Database was opened in read-only mode so message cannot 
+                     be modified.
+                   STATUS.NOT_INITIALIZED
+                     The message has not been initialized.
+        """
+        if self._msg is None:
+            raise NotmuchError(STATUS.NOT_INITIALIZED)
+
+        status = nmlib.notmuch_message_remove_tag(self._msg, tag)
+
+        if STATUS.SUCCESS == status:
+            # return on success
+            return status
+
+        raise NotmuchError(status)
+
+    def remove_all_tags(self):
+        """Removes all tags from the given message.
+
+        See :meth:`freeze` for an example showing how to safely
+        replace tag values.
+
+        :returns: STATUS.SUCCESS if the tags were successfully removed.
+                  Raises an exception otherwise.
+        :exception: :exc:`NotmuchError`. They have the following meaning:
+
+                   STATUS.READ_ONLY_DATABASE
+                     Database was opened in read-only mode so message cannot 
+                     be modified.
+                   STATUS.NOT_INITIALIZED
+                     The message has not been initialized.
+        """
+        if self._msg is None:
+            raise NotmuchError(STATUS.NOT_INITIALIZED)
+ 
+        status = nmlib.notmuch_message_remove_all_tags(self._msg)
+
+        if STATUS.SUCCESS == status:
+            # return on success
+            return status
+
+        raise NotmuchError(status)
+
+    def freeze(self):
+        """Freezes the current state of 'message' within the database
+
+        This means that changes to the message state, (via :meth:`add_tag`, 
+        :meth:`remove_tag`, and :meth:`remove_all_tags`), will not be 
+        committed to the database until the message is :meth:`thaw`ed.
+
+        Multiple calls to freeze/thaw are valid and these calls will
+        "stack". That is there must be as many calls to thaw as to freeze
+        before a message is actually thawed.
+
+        The ability to do freeze/thaw allows for safe transactions to
+        change tag values. For example, explicitly setting a message to
+        have a given set of tags might look like this::
+
+          msg.freeze()
+          msg.remove_all_tags()
+          for tag in new_tags:
+              msg.add_tag(tag)
+          msg.thaw()
+
+        With freeze/thaw used like this, the message in the database is
+        guaranteed to have either the full set of original tag values, or
+        the full set of new tag values, but nothing in between.
+
+        Imagine the example above without freeze/thaw and the operation
+        somehow getting interrupted. This could result in the message being
+        left with no tags if the interruption happened after
+        :meth:`remove_all_tags` but before :meth:`add_tag`.
+
+        :returns: STATUS.SUCCESS if the message was successfully frozen.
+                  Raises an exception otherwise.
+        :exception: :exc:`NotmuchError`. They have the following meaning:
+
+                   STATUS.READ_ONLY_DATABASE
+                     Database was opened in read-only mode so message cannot 
+                     be modified.
+                   STATUS.NOT_INITIALIZED
+                     The message has not been initialized.
+        """
+        if self._msg is None:
+            raise NotmuchError(STATUS.NOT_INITIALIZED)
+ 
+        status = nmlib.notmuch_message_freeze(self._msg)
+
+        if STATUS.SUCCESS == status:
+            # return on success
+            return status
+
+        raise NotmuchError(status)
+
+    def thaw(self):
+        """Thaws the current 'message'
+
+        Thaw the current 'message', synchronizing any changes that may have 
+        occurred while 'message' was frozen into the notmuch database.
+
+        See :meth:`freeze` for an example of how to use this
+        function to safely provide tag changes.
+
+        Multiple calls to freeze/thaw are valid and these calls with
+        "stack". That is there must be as many calls to thaw as to freeze
+        before a message is actually thawed.
+
+        :returns: STATUS.SUCCESS if the message was successfully frozen.
+                  Raises an exception otherwise.
+        :exception: :exc:`NotmuchError`. They have the following meaning:
+
+                   STATUS.UNBALANCED_FREEZE_THAW
+                     An attempt was made to thaw an unfrozen message. 
+                     That is, there have been an unbalanced number of calls 
+                     to :meth:`freeze` and :meth:`thaw`.
+                   STATUS.NOT_INITIALIZED
+                     The message has not been initialized.
+        """
+        if self._msg is None:
+            raise NotmuchError(STATUS.NOT_INITIALIZED)
+ 
+        status = nmlib.notmuch_message_thaw(self._msg)
+
+        if STATUS.SUCCESS == status:
+            # return on success
+            return status
+
+        raise NotmuchError(status)
+
+    

     def __str__(self):
         """A message() is represented by a 1-line summary"""
         msg = {}
     def __str__(self):
         """A message() is represented by a 1-line summary"""
         msg = {}


@@ -518,7 +926,7 @@ class Message(object):
         return "%(from)s (%(date)s) (%(tags)s)" % (msg)
 
     def format_as_text(self):
         return "%(from)s (%(date)s) (%(tags)s)" % (msg)
 
     def format_as_text(self):

-        """ Output like notmuch show """
+        """Output like notmuch show (Not implemented)"""

         return str(self)
 
     def __del__(self):
         return str(self)
 
     def __del__(self):