logviewer: avoid memory-mapped files, make it work when opened a second time

pyfpdb/GuiLogView.py

@@ -17,8 +17,8 @@
 #agpl-3.0.txt in the docs folder of the package.
 
 
-import mmap
+import os
-import threading
+import Queue
 
 import pygtk
 pygtk.require('2.0')
@@ -30,13 +30,16 @@ import Configuration
 
 log = Configuration.get_logger("logging.conf", "logview")
 
-MAX_LINES = 100000
+MAX_LINES = 100000         # max lines to display in window
+EST_CHARS_PER_LINE = 150   # used to guesstimate number of lines in log file
+logfile = 'logging.out'    # name of logfile
 
 class GuiLogView:
 
-    def __init__(self, config, mainwin):
+    def __init__(self, config, mainwin, closeq):
         self.config = config
         self.main_window = mainwin
+        self.closeq = closeq
 
         self.dia = gtk.Dialog(title="Log Messages"
                              ,parent=None
@@ -88,6 +91,7 @@ class GuiLogView:
 
     def dialog_response_cb(self, dialog, response_id):
         # this is called whether close button is pressed or window is closed
+        self.closeq.put(self.__class__)
         dialog.destroy()
 
     def get_dialog(self):
@@ -109,39 +113,28 @@ class GuiLogView:
 
     def loadLog(self):
 
-        #self.configStore = gtk.TreeStore(gobject.TYPE_PYOBJECT, gobject.TYPE_STRING, gobject.TYPE_STRING)
-        #self.configView = gtk.TreeView(self.configStore)
-        #self.configView.set_enable_tree_lines(True)
         self.liststore.clear()
         self.listcols = []
 
-        # count number of lines in file
+        # guesstimate number of lines in file
-        f = open('logging.out', "r+")
+        if os.path.exists(logfile):
-        buf = mmap.mmap(f.fileno(), 0)
+            stat_info = os.stat(logfile)
-        readline = buf.readline
+            lines = stat_info.st_size / EST_CHARS_PER_LINE
-        lines = 0
+            print "logview: size =", stat_info.st_size, "lines =", lines
-        while readline():
-            lines += 1
-        f.close()
 
-        startline = 0
+            # set startline to line number to start display from
-        if lines > MAX_LINES:
+            startline = 0
-            # only display from startline if log file is large
+            if lines > MAX_LINES:
-            startline = lines - MAX_LINES
+                # only display from startline if log file is large
+                startline = lines - MAX_LINES
 
-        f = open('logging.out', "r+")
+            l = 0
-        buf = mmap.mmap(f.fileno(), 0)
+            for line in open(logfile):
-        readline = buf.readline
+                # eg line:
-        l = 0
+                # 2009-12-02 15:23:21,716 - config       DEBUG    config logger initialised
-        line = readline()
+                l = l + 1
-        while line:
+                if l > startline and len(line) > 49:
-            # eg line:
+                    iter = self.liststore.append( (line[0:23], line[26:32], line[39:46], line[48:].strip(), True) )
-            # 2009-12-02 15:23:21,716 - config       DEBUG    config logger initialised
-            l = l + 1
-            if l > startline and len(line) > 49:
-                iter = self.liststore.append( (line[0:23], line[26:32], line[39:46], line[48:].strip(), True) )
-            line = readline()
-        f.close()
 
     def sortCols(self, col, n):
         try:

pyfpdb/fpdb.py

@@ -18,6 +18,7 @@
 import os
 import sys
 import re
+import Queue
 
 # if path is set to use an old version of python look for a new one:
 # (does this work in linux?)
@@ -485,14 +486,22 @@ class fpdb:
         #if self.obtain_global_lock():
         #    lock_set = True
 
+        # remove members from self.threads if close messages received
+        self.process_close_messages()
+
+        viewer = None
         for i, t in enumerate(self.threads):
             if str(t.__class__) == 'GuiLogView.GuiLogView':
-                # show existing log window
+                viewer = t
-                t.get_dialog().present()
+                break
-                return
 
-        new_thread = GuiLogView.GuiLogView(self.config, self.window)
+        if viewer is None:
-        self.threads.append(new_thread)
+            #print "creating new log viewer"
+            new_thread = GuiLogView.GuiLogView(self.config, self.window, self.closeq)
+            self.threads.append(new_thread)
+        else:
+            #print "showing existing log viewer"
+            viewer.get_dialog().present()
 
         #if lock_set:
         #    self.release_global_lock()
@@ -502,6 +511,21 @@ class fpdb:
         self.logbuffer.insert(end_iter, text)
         self.logview.scroll_to_mark(self.logbuffer.get_insert(), 0)
 
+
+    def process_close_messages(self):
+        # check for close messages
+        try:
+            while True:
+                name = self.closeq.get(False)
+                for i, t in enumerate(self.threads):
+                    if str(t.__class__) == str(name):
+                        # thread has ended so remove from list:
+                        del self.threads[i]
+                        break
+        except Queue.Empty:
+            # no close messages on queue, do nothing
+            pass
+
     def __calendar_dialog(self, widget, entry):
         self.dia_confirm.set_modal(False)
         d = gtk.Window(gtk.WINDOW_TOPLEVEL)
@@ -846,6 +870,7 @@ This program is licensed under the AGPL3, see docs"""+os.sep+"agpl-3.0.txt")
         #done menubar
 
         self.threads = []     # objects used by tabs - no need for threads, gtk handles it
+        self.closeq = Queue.Queue(20)  # used to signal ending of a thread (only logviewer for now)
 
         self.nb = gtk.Notebook()
         self.nb.set_show_tabs(True)