Simplify history retrieval code by moving query building and running into a common helper function.

IPython/core/history.py

@@ -1,589 +1,596 b''
 """ History related magics and functionality """
 #-----------------------------------------------------------------------------
 #  Copyright (C) 2010 The IPython Development Team.
 #
 #  Distributed under the terms of the BSD License.
 #
 #  The full license is in the file COPYING.txt, distributed with this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 from __future__ import print_function
 
 # Stdlib imports
 import os
 import re
 import sqlite3
 
 # Our own packages
 from IPython.config.configurable import Configurable
 import IPython.utils.io
 
 from IPython.testing import decorators as testdec
 from IPython.utils.io import ask_yes_no
 from IPython.utils.traitlets import Bool, Dict, Instance, Int, List, Unicode
 from IPython.utils.warn import warn
 
 #-----------------------------------------------------------------------------
 # Classes and functions
 #-----------------------------------------------------------------------------
 
 class HistoryManager(Configurable):
     """A class to organize all history-related functionality in one place.
     """
     # Public interface
 
     # An instance of the IPython shell we are attached to
     shell = Instance('IPython.core.interactiveshell.InteractiveShellABC')
     # Lists to hold processed and raw history. These start with a blank entry
     # so that we can index them starting from 1
     input_hist_parsed = List([""])
     input_hist_raw = List([""])
     # A list of directories visited during session
     dir_hist = List()
     # A dict of output history, keyed with ints from the shell's execution count
     output_hist = Dict()
     # String holding the path to the history file
     hist_file = Unicode()
     # The SQLite database
     db = Instance(sqlite3.Connection)
     # The number of the current session in the history database
     session_number = Int()
     # Should we log output to the database? (default no)
     db_log_output = Bool(False, config=True)
     # Write to database every x commands (higher values save disk access & power)
     #  Values of 1 or less effectively disable caching. 
     db_cache_size = Int(0, config=True)
     # The input and output caches
     db_input_cache = List()
     db_output_cache = List()
     
     # Private interface
     # Variables used to store the three last inputs from the user.  On each new
     # history update, we populate the user's namespace with these, shifted as
     # necessary.
     _i00, _i, _ii, _iii = '','','',''
 
     # A set with all forms of the exit command, so that we don't store them in
     # the history (it's annoying to rewind the first entry and land on an exit
     # call).
     _exit_commands = None
     
     def __init__(self, shell, config=None):
         """Create a new history manager associated with a shell instance.
         """
         # We need a pointer back to the shell for various tasks.
         super(HistoryManager, self).__init__(shell=shell, config=config)
 
         # list of visited directories
         try:
             self.dir_hist = [os.getcwd()]
         except OSError:
             self.dir_hist = []
 
         # Now the history file
         if shell.profile:
             histfname = 'history-%s' % shell.profile
         else:
             histfname = 'history'
         self.hist_file = os.path.join(shell.ipython_dir, histfname + '.sqlite')
         self.init_db()
     
         self._i00, self._i, self._ii, self._iii = '','','',''
 
         self._exit_commands = set(['Quit', 'quit', 'Exit', 'exit', '%Quit',
                                    '%quit', '%Exit', '%exit'])
         
     def init_db(self):
         """Connect to the database and get new session number."""
         self.db = sqlite3.connect(self.hist_file)
         self.db.execute("""CREATE TABLE IF NOT EXISTS history 
                 (session integer, line integer, source text, source_raw text,
                 PRIMARY KEY (session, line))""")
         # Output history is optional, but ensure the table's there so it can be
         # enabled later.
         self.db.execute("""CREATE TABLE IF NOT EXISTS output_history
                         (session integer, line integer, output text,
                         PRIMARY KEY (session, line))""")
         cur = self.db.execute("""SELECT name FROM sqlite_master WHERE
                                 type='table' AND name='singletons'""")
         if not cur.fetchone():
             self.db.execute("""CREATE TABLE singletons
                             (name text PRIMARY KEY, value)""")
             self.db.execute("""INSERT INTO singletons VALUES
                             ('session_number', 1)""")
             self.db.commit()
         cur = self.db.execute("""SELECT value FROM singletons WHERE
                               name='session_number'""")
         self.session_number = cur.fetchone()[0]
         
         #Increment by one for next session.
         self.db.execute("""UPDATE singletons SET value=? WHERE
                         name='session_number'""", (self.session_number+1,))
         self.db.commit()
                             
-    def get_hist_tail(self, n=10, raw=True, output=False):
-        """Get the last n lines from the history database."""
+    def _get_hist_sql(self, sql, params, raw=True, output=False):
+        """Prepares and runs an SQL query for the history database.
+        
+        Parameters
+        ----------
+        sql : str
+          Any filtering expressions to go after SELECT ... FROM ...
+        params : tuple
+          Parameters passed to the SQL query (to replace "?")
+        raw : bool
+          If True, get raw input.
+        output : 
+          If True, include output where available.
+        
+        Returns
+        -------
+        An iterator over 3-tuples: (session, line_number, command), or if output
+        is True, (session, line_number, (command, output)).
+        """
         toget = 'source_raw' if raw else 'source'
         sqlfrom = "history"
         if output:
             sqlfrom = "history LEFT JOIN output_history USING (session, line)"
             toget = "history.%s, output_history.output" % toget
-        cur = self.db.execute("SELECT session, line, " + toget +\
-            " FROM "+sqlfrom+" ORDER BY session DESC, line DESC LIMIT ?", (n,))
-        hist = reversed(cur.fetchall())
-        if output:
-            return ((ses, lin, (inp, out)) for ses, lin, inp, out in hist)
-        return hist
+        cur = self.db.execute("SELECT session, line, %s FROM %s " %\
+                                (toget, sqlfrom) + sql, params)
+        if output:    # Regroup into 3-tuples
+            return ((ses, lin, (inp, out)) for ses, lin, inp, out in cur)
+        return cur
+        
+    
+    def get_hist_tail(self, n=10, raw=True, output=False):
+        """Get the last n lines from the history database."""
+        cur = self._get_hist_sql("ORDER BY session DESC, line DESC LIMIT ?",
+                                (n,), raw=raw, output=output)
+        return reversed(list(cur))
         
     def get_hist_search(self, pattern="*", raw=True, output=False):
         """Search the database using unix glob-style matching (wildcards * and
         ?, escape using \).
         
         Returns
         -------
         An iterator over tuples: (session, line_number, command)
         """
-        toget = "source_raw" if raw else "source"
-        tosearch = toget
-        sqlfrom = "history"
+        tosearch = "source_raw" if raw else "source"
         if output:
-            sqlfrom = "history LEFT JOIN output_history USING (session, line)"
-            toget = "history.%s, output_history.output" % toget
             tosearch = "history." + tosearch
-        hist = self.db.execute("SELECT session, line, " +toget+ \
-                    " FROM "+sqlfrom+" WHERE " +tosearch+ " GLOB ?", (pattern,))
-        if output:
-            return ((ses, lin, (inp, out)) for ses, lin, inp, out in hist)
-        return hist
+        return self._get_hist_sql("WHERE %s GLOB ?" % tosearch, (pattern,),
+                                    raw=raw, output=output)
                                 
     def _get_hist_session(self, start=1, stop=None, raw=True, output=False):
         """Get input and output history from the current session. Called by
         get_history, and takes similar parameters."""
         input_hist = self.input_hist_raw if raw else self.input_hist_parsed
             
         n = len(input_hist)
         if start < 0:
             start += n
         if not stop:
             stop = n
         elif stop < 0:
             stop += n
         
         for i in range(start, stop):
             if output:
                 line = (input_hist[i], repr(self.output_hist.get(i)))
             else:
                 line = input_hist[i]
             yield (0, i, line)
             
     def get_history(self, session=0, start=1, stop=None, raw=True,output=False):
         """Retrieve input by session.
         
         Parameters
         ----------
         session : int
             Session number to retrieve. The current session is 0, and negative
             numbers count back from current session, so -1 is previous session.
         start : int
             First line to retrieve.
         stop : int
             End of line range (excluded from output itself). If None, retrieve
             to the end of the session.
         raw : bool
             If True, return untranslated input
         output : bool
             If True, attempt to include output. This will be 'real' Python
             objects for the current session, or text reprs from previous
             sessions if db_log_output was enabled at the time. Where no output
             is found, None is used.
             
         Returns
         -------
         An iterator over the desired lines. Each line is a 3-tuple, either
         (session, line, input) if output is False, or
         (session, line, (input, output)) if output is True.
         """
         if session == 0 or session==self.session_number:   # Current session
             return self._get_hist_session(start, stop, raw, output)
         if session < 0:
             session += self.session_number
             
-        # Assemble the SQL query:
-        sqlfrom = "history"
-        toget = 'source_raw' if raw else 'source'
-        if output:
-            sqlfrom = "history LEFT JOIN output_history USING (session, line)"
-            toget = "history.%s, output_history.output" % toget
         if stop:
             lineclause = "line >= ? AND line < ?"
             params = (session, start, stop)
         else:
             lineclause = "line>=?"
             params = (session, start)
         
-        cur = self.db.execute("""SELECT session, line, %s FROM %s WHERE
-            session==? AND %s""" %(toget, sqlfrom, lineclause), params)
-        if output:     # Regroup into 3-tuples
-            return ((ses, lin, (inp, out)) for ses, lin, inp, out in cur)
-        return cur
+        return self._get_hist_sql("WHERE session==? AND %s""" % lineclause,
+                                    params, raw=raw, output=output)
         
     def get_hist_from_rangestr(self, rangestr, raw=True, output=False):
         """Get lines of history from a string of ranges, as used by magic
         commands %hist, %save, %macro, etc."""
         for sess, s, e in extract_hist_ranges(rangestr):
             for line in self.get_history(sess, s, e, raw=raw, output=output):
                 yield line
 
     def store_inputs(self, line_num, source, source_raw=None):
         """Store source and raw input in history and create input cache
         variables _i*.
         
         Parameters
         ----------
         line_num : int
           The prompt number of this input.
         
         source : str
           Python input.
 
         source_raw : str, optional
           If given, this is the raw input without any IPython transformations
           applied to it.  If not given, ``source`` is used.
         """
         if source_raw is None:
             source_raw = source
             
         # do not store exit/quit commands
         if source_raw.strip() in self._exit_commands:
             return
         
         self.input_hist_parsed.append(source.rstrip())
         self.input_hist_raw.append(source_raw.rstrip())
         
         self.db_input_cache.append((self.session_number, line_num,
                                     source, source_raw))
         # Trigger to flush cache and write to DB.
         if len(self.db_input_cache) >= self.db_cache_size:
             self.writeout_cache()
 
         # update the auto _i variables
         self._iii = self._ii
         self._ii = self._i
         self._i = self._i00
         self._i00 = source_raw
 
         # hackish access to user namespace to create _i1,_i2... dynamically
         new_i = '_i%s' % line_num
         to_main = {'_i': self._i,
                    '_ii': self._ii,
                    '_iii': self._iii,
                    new_i : self._i00 }
         self.shell.user_ns.update(to_main)
         
     def store_output(self, line_num, output):
         if not self.db_log_output:
             return
         db_row = (self.session_number, line_num, output)
         if self.db_cache_size > 1:
             self.db_output_cache.append(db_row)
         else:
           with self.db:
             self.db.execute("INSERT INTO output_history VALUES (?,?,?)", db_row)
         
     def writeout_cache(self):
         #print(self.db_input_cache)
         with self.db:
             self.db.executemany("INSERT INTO history VALUES (?, ?, ?, ?)",
                                 self.db_input_cache)
             self.db.executemany("INSERT INTO output_history VALUES (?, ?, ?)",
                                 self.db_output_cache)
         self.db_input_cache = []
         self.db_output_cache = []
 
     def sync_inputs(self):
         """Ensure raw and translated histories have same length."""
         lr = len(self.input_hist_raw)
         lp = len(self.input_hist_parsed)
         if lp < lr:
             self.input_hist_raw[:lr-lp] = []
         elif lr < lp:
             self.input_hist_parsed[:lp-lr] = []
 
     def reset(self, new_session=True):
         """Clear the current session's history, and (optionally) start a new
         session."""
         self.input_hist_parsed[:] = [""]
         self.input_hist_raw[:] = [""]
         self.output_hist.clear()
         # The directory history can't be completely empty
         self.dir_hist[:] = [os.getcwd()]
         
         if new_session:
             self.writeout_cache()
             self.init_db()     # Get new session number
         
 # To match, e.g. ~5/8-~2/3
 range_re = re.compile(r"""
 ((?P<startsess>~?\d+)/)?
 (?P<start>\d+)                    # Only the start line num is compulsory
 ((?P<sep>[\-:])
  ((?P<endsess>~?\d+)/)?
  (?P<end>\d+))?
 """, re.VERBOSE)
 
 def extract_hist_ranges(ranges_str):
     """Turn a string of history ranges into 3-tuples of (session, start, stop).
     
     Examples
     --------
     list(extract_input_ranges("~8/5-~7/4 2"))
     [(-8, 5, None), (-7, 1, 4), (0, 2, 3)]
     """
     for range_str in ranges_str.split():
         rmatch = range_re.match(range_str)
         start = int(rmatch.group("start"))
         end = rmatch.group("end")
         end = int(end) if end else start+1   # If no end specified, get (a, a+1)
         if rmatch.group("sep") == "-":       # 1-3 == 1:4 --> [1, 2, 3]
             end += 1
         startsess = rmatch.group("startsess") or "0"
         endsess = rmatch.group("endsess") or startsess
         startsess = int(startsess.replace("~","-"))
         endsess = int(endsess.replace("~","-"))
         assert endsess >= startsess
 
         if endsess == startsess:
             yield (startsess, start, end)
             continue
         # Multiple sessions in one range:
         yield (startsess, start, None)
         for sess in range(startsess+1, endsess):
             yield (sess, 1, None)
         yield (endsess, 1, end)
 
 def _format_lineno(session, line):
     """Helper function to format line numbers properly."""
     if session == 0:
         return str(line)
     return "%s#%s" % (session, line)
 
 @testdec.skip_doctest
 def magic_history(self, parameter_s = ''):
     """Print input history (_i<n> variables), with most recent last.
     
     %history       -> print at most 40 inputs (some may be multi-line)\\
     %history n     -> print at most n inputs\\
     %history n1 n2 -> print inputs between n1 and n2 (n2 not included)\\
 
     By default, input history is printed without line numbers so it can be
     directly pasted into an editor.
 
     With -n, each input's number <n> is shown, and is accessible as the
     automatically generated variable _i<n> as well as In[<n>].  Multi-line
     statements are printed starting at a new line for easy copy/paste.
 
     Options:
 
       -n: print line numbers for each input.
       This feature is only available if numbered prompts are in use.
 
       -o: also print outputs for each input.
 
       -p: print classic '>>>' python prompts before each input.  This is useful
        for making documentation, and in conjunction with -o, for producing
        doctest-ready output.
 
       -r: (default) print the 'raw' history, i.e. the actual commands you typed.
       
       -t: print the 'translated' history, as IPython understands it.  IPython
       filters your input and converts it all into valid Python source before
       executing it (things like magics or aliases are turned into function
       calls, for example). With this option, you'll see the native history
       instead of the user-entered version: '%cd /' will be seen as
       'get_ipython().magic("%cd /")' instead of '%cd /'.
       
       -g: treat the arg as a pattern to grep for in (full) history.
       This includes the saved history (almost all commands ever written).
       Use '%hist -g' to show full saved history (may be very long).
       
       -l: get the last n lines from all sessions. Specify n as a single arg, or
       the default is the last 10 lines.
 
       -f FILENAME: instead of printing the output to the screen, redirect it to
        the given file.  The file is always overwritten, though IPython asks for
        confirmation first if it already exists.
        
     Examples
     --------
     ::
     
       In [6]: %hist -n 4 6
       4:a = 12
       5:print a**2
 
     """
 
     if not self.shell.displayhook.do_full_cache:
         print('This feature is only available if numbered prompts are in use.')
         return
     opts,args = self.parse_options(parameter_s,'noprtglf:',mode='string')
     
     # For brevity
     history_manager = self.shell.history_manager
     
     def _format_lineno(session, line):
         """Helper function to format line numbers properly."""
         if session in (0, history_manager.session_number):
             return str(line)
         return "%s/%s" % (session, line)
 
     # Check if output to specific file was requested.
     try:
         outfname = opts['f']
     except KeyError:
         outfile = IPython.utils.io.Term.cout  # default
         # We don't want to close stdout at the end!
         close_at_end = False
     else:
         if os.path.exists(outfname):
             if not ask_yes_no("File %r exists. Overwrite?" % outfname): 
                 print('Aborting.')
                 return
 
         outfile = open(outfname,'w')
         close_at_end = True
     
     print_nums = 'n' in opts
     get_output = 'o' in opts
     pyprompts = 'p' in opts
     # Raw history is the default
     raw = not('t' in opts)
             
     default_length = 40
     pattern = None
     
     if 'g' in opts:         # Glob search
         pattern = "*" + args + "*" if args else "*"
         hist = history_manager.get_hist_search(pattern, raw=raw,
                                                               output=get_output)
     elif 'l' in opts:       # Get 'tail'
         try:
             n = int(args)
         except ValueError, IndexError:
             n = 10
         hist = history_manager.get_hist_tail(n, raw=raw, output=get_output)
     else:
         if args:            # Get history by ranges
             hist = history_manager.get_hist_from_rangestr(args, raw, get_output)
         else:               # Just get history for the current session
             hist = history_manager.get_history(raw=raw, output=get_output)
     
     # We could be displaying the entire history, so let's not try to pull it 
     # into a list in memory. Anything that needs more space will just misalign.
     width = 4
         
     for session, lineno, inline in hist:
         # Print user history with tabs expanded to 4 spaces.  The GUI clients
         # use hard tabs for easier usability in auto-indented code, but we want
         # to produce PEP-8 compliant history for safe pasting into an editor.
         if get_output:
             inline, output = inline
         inline = inline.expandtabs(4).rstrip()
             
         multiline = "\n" in inline
         line_sep = '\n' if multiline else ' '
         if print_nums:
             print('%s:%s' % (_format_lineno(session, lineno).rjust(width),
                     line_sep),  file=outfile, end='')
         if pyprompts:
             print(">>> ", end="", file=outfile)
             if multiline:
                 inline = "\n... ".join(inline.splitlines()) + "\n..."
         print(inline, file=outfile)
         if get_output and output:
             print(output, file=outfile)
 
     if close_at_end:
         outfile.close()
 
 # %hist is an alternative name
 magic_hist = magic_history
 
 
 def rep_f(self, arg):
     r""" Repeat a command, or get command to input line for editing
 
     - %rep (no arguments):
     
     Place a string version of last computation result (stored in the special '_'
     variable) to the next input prompt. Allows you to create elaborate command
     lines without using copy-paste::
     
         $ l = ["hei", "vaan"]       
         $ "".join(l)        
         ==> heivaan        
         $ %rep        
         $ heivaan_ <== cursor blinking    
     
     %rep 45
     
     Place history line 45 to next input prompt. Use %hist to find out the
     number.
     
     %rep 1-4 6-7 3
     
     Repeat the specified lines immediately. Input slice syntax is the same as
     in %macro and %save.
     
     %rep foo
     
     Place the most recent line that has the substring "foo" to next input.
     (e.g. 'svn ci -m foobar').    
     """
     
     opts,args = self.parse_options(arg,'',mode='list')
     if not args:
         self.set_next_input(str(self.shell.user_ns["_"]))
         return
 
     if len(args) == 1 and not '-' in args[0]:
         arg = args[0]
         if len(arg) > 1 and arg.startswith('0'):
             # get from shadow hist
             num = int(arg[1:])
             line = self.shell.shadowhist.get(num)
             self.set_next_input(str(line))
             return
         try:
             num = int(args[0])
             self.set_next_input(str(self.shell.input_hist_raw[num]).rstrip())
             return
         except ValueError:
             pass
         
         for h in reversed(self.shell.input_hist_raw):
             if 'rep' in h:
                 continue
             if fnmatch.fnmatch(h,'*' + arg + '*'):
                 self.set_next_input(str(h).rstrip())
                 return
         
     try:
         lines = self.extract_input_slices(args, True)
         print("lines", lines)
         self.run_cell(lines)
     except ValueError:
         print("Not found in recent history:", args)
 
 
 def init_ipython(ip):
     ip.define_magic("rep",rep_f)        
     ip.define_magic("hist",magic_hist)            
     ip.define_magic("history",magic_history)
 
     # XXX - ipy_completers are in quarantine, need to be updated to new apis
     #import ipy_completers
     #ipy_completers.quick_completer('%hist' ,'-g -t -r -n')