diff options
| -rw-r--r-- | Lib/distutils/text_file.py | 47 |
1 files changed, 18 insertions, 29 deletions
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 @@ class TextFile: 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 @@ class TextFile: 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 @@ class TextFile: 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 @@ class TextFile: 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 @@ class TextFile: 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 @@ class TextFile: # 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 @@ class TextFile: lines.append (line) + def unreadline (self, line): + self.linebuf.append (line) + + if __name__ == "__main__": test_data = """# test file |