Replaced the last attempt at an "unreadline" with one that actually
works on non-seekable file-like objects, such as URLs. (Oops.)
diff --git a/Lib/distutils/text_file.py b/Lib/distutils/text_file.py
index 1d57956..bc56a49 100644
--- a/Lib/distutils/text_file.py
+++ b/Lib/distutils/text_file.py
@@ -53,10 +53,10 @@
self.file = file
self.current_line = 0 # assuming that file is at BOF!
- # 'linestart' stores the file offset of the start of each logical
- # line; it is used to back up the file pointer when the caller
- # wants to "unread" a line
- self.linestart = []
+ # 'linebuf' is a stack of lines that will be emptied before we
+ # actually read from the file; it's only populated by an
+ # 'unreadline()' operation
+ self.linebuf = []
def open (self, filename):
@@ -83,14 +83,18 @@
def readline (self):
+ # If any "unread" lines waiting in 'linebuf', return the top
+ # one. (We don't actually buffer read-ahead data -- lines only
+ # get put in 'linebuf' if the client explicitly does an
+ # 'unreadline()'.
+ if self.linebuf:
+ line = self.linebuf[-1]
+ del self.linebuf[-1]
+ return line
+
buildup_line = ''
while 1:
- # record current file position; this will be appended to
- # the linestart array *unless* we're accumulating a
- # continued logical line
- current_pos = self.file.tell()
-
# read the line, optionally strip comments
line = self.file.readline()
if self.strip_comments and line:
@@ -111,11 +115,6 @@
self.current_line[1] = self.current_line[1] + 1
else:
self.current_line = [self.current_line, self.current_line+1]
-
- # Forget current position: don't want to save it in the
- # middle of a logical line
- current_pos = None
-
# just an ordinary line, read it as usual
else:
if not line:
@@ -126,7 +125,7 @@
self.current_line = self.current_line[1] + 1
else:
self.current_line = self.current_line + 1
-
+
# strip whitespace however the client wants (leading and
# trailing, or one or the other, or neither)
@@ -143,12 +142,6 @@
if line == '' or line == '\n' and self.skip_blanks:
continue
- # if we're still here and have kept the current position,
- # then this physical line starts a logical line; record its
- # starting offset
- if current_pos is not None:
- self.linestart.append (current_pos)
-
if self.join_lines:
if line[-1] == '\\':
buildup_line = line[:-1]
@@ -168,14 +161,6 @@
# end readline
- def unreadline (self):
- if not self.linestart:
- raise IOError, "at beginning of file -- can't unreadline"
- pos = self.linestart[-1]
- del self.linestart[-1]
- self.file.seek (pos)
-
-
def readlines (self):
lines = []
while 1:
@@ -185,6 +170,10 @@
lines.append (line)
+ def unreadline (self, line):
+ self.linebuf.append (line)
+
+
if __name__ == "__main__":
test_data = """# test file