Added libbe.pager and --paginate/--no-pager options to be.

3 files changed, 82 insertions, 2 deletions

diff --git a/NEWS b/NEWS
index 84256e1..53804e6 100644
--- a/NEWS
+++ b/NEWS
@@ -1,4 +1,5 @@
-December 6, 2009
+December 7, 2009
+ * added --paginate and --no-pager to be.
  * be --dir DIR COMMAND now roots the bugdir in DIR _without_ changing
    directories.
  * `be init --root DIR` should now be `be --dir DIR init`.
diff --git a/be b/be
index 8a594cf..f026c05 100755
--- a/be
+++ b/be
@@ -22,7 +22,7 @@
 import os
 import sys
 
-from libbe import cmdutil, version
+from libbe import cmdutil, version, pager
 
 __doc__ = cmdutil.help()
 
@@ -36,6 +36,13 @@ parser.add_option("--verbose-version", action="store_true", dest="verbose_versio
                   help="Print verbose version information and exit.")
 parser.add_option("-d", "--dir", dest="dir", metavar="DIR", default=".",
                   help="Run this command on the repository in DIR instead of the current directory.")
+parser.add_option("-p", "--paginate", dest="paginate", default=False,
+                  action='store_true',
+                  help="Pipe all output into less (or if set, $PAGER).")
+parser.add_option("--no-pager", dest="no_pager", default=False,
+                  action='store_true',
+                  help="Do not pipe git output into a pager.")
+
 
 try:
     options,args = parser.parse_args()
@@ -57,6 +64,13 @@ if options.version == True or options.verbose_version == True:
     print version.version(verbose=options.verbose_version)
     sys.exit(0)
 
+paginate = 'auto'
+if options.paginate == True:
+    paginate = 'always'
+if options.no_pager== True:
+    paginate = 'never'
+pager.run_pager(paginate)
+
 try:
     if len(args) == 0:
         raise cmdutil.UsageError, "must supply a command"
diff --git a/libbe/pager.py b/libbe/pager.py
new file mode 100644
index 0000000..1ddc3fa
--- /dev/null
+++ b/libbe/pager.py
@@ -0,0 +1,65 @@
+# Copyright (C) 2009 W. Trevor King <wking@drexel.edu>
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License along
+# with this program; if not, write to the Free Software Foundation, Inc.,
+# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+"""
+Automatic pager for terminal output (a la Git).
+"""
+
+import sys, os, select
+
+# see http://nex-3.com/posts/73-git-style-automatic-paging-in-ruby
+def run_pager(paginate='auto'):
+    """
+    paginate should be one of 'never', 'auto', or 'always'.
+
+    usage: just call this function and continue using sys.stdout like
+    you normally would.
+    """
+    if paginate == 'never' \
+            or sys.platform == 'win32' \
+            or not hasattr(sys.stdout, 'isatty') \
+            or sys.stdout.isatty() == False:
+        return
+
+    if paginate == 'auto':
+        if 'LESS' not in os.environ:
+            os.environ['LESS'] = '' # += doesn't work on undefined var
+        # don't page if the input is short enough
+        os.environ['LESS'] += ' -FRX'
+    if 'PAGER' in os.environ:
+        pager = os.environ['PAGER']
+    else:
+        pager = 'less'
+
+    read_fd, write_fd = os.pipe()
+    if os.fork() == 0:
+        # child process
+        os.close(read_fd)
+        os.close(0)
+        os.dup2(write_fd, 1)
+        os.close(write_fd)
+        if hasattr(sys.stderr, 'isatty') and sys.stderr.isatty() == True:
+            os.dup2(1, 2)
+        return
+
+    # parent process, become pager
+    os.close(write_fd)
+    os.dup2(read_fd, 0)
+    os.close(read_fd)
+
+    # Wait until we have input before we start the pager
+    select.select([0], [], [])
+    os.execlp(pager, pager)