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Diffstat (limited to 'Lib/distutils/text_file.py')
| -rw-r--r-- | Lib/distutils/text_file.py | 286 |
1 files changed, 0 insertions, 286 deletions
diff --git a/Lib/distutils/text_file.py b/Lib/distutils/text_file.py deleted file mode 100644 index 93abad3..0000000 --- a/Lib/distutils/text_file.py +++ /dev/null @@ -1,286 +0,0 @@ -"""text_file - -provides the TextFile class, which gives an interface to text files -that (optionally) takes care of stripping comments, ignoring blank -lines, and joining lines with backslashes.""" - -import sys, io - - -class TextFile: - """Provides a file-like object that takes care of all the things you - commonly want to do when processing a text file that has some - line-by-line syntax: strip comments (as long as "#" is your - comment character), skip blank lines, join adjacent lines by - escaping the newline (ie. backslash at end of line), strip - leading and/or trailing whitespace. All of these are optional - and independently controllable. - - Provides a 'warn()' method so you can generate warning messages that - report physical line number, even if the logical line in question - spans multiple physical lines. Also provides 'unreadline()' for - implementing line-at-a-time lookahead. - - Constructor is called as: - - TextFile (filename=None, file=None, **options) - - It bombs (RuntimeError) if both 'filename' and 'file' are None; - 'filename' should be a string, and 'file' a file object (or - something that provides 'readline()' and 'close()' methods). It is - recommended that you supply at least 'filename', so that TextFile - can include it in warning messages. If 'file' is not supplied, - TextFile creates its own using 'io.open()'. - - The options are all boolean, and affect the value returned by - 'readline()': - strip_comments [default: true] - strip from "#" to end-of-line, as well as any whitespace - leading up to the "#" -- unless it is escaped by a backslash - lstrip_ws [default: false] - strip leading whitespace from each line before returning it - rstrip_ws [default: true] - strip trailing whitespace (including line terminator!) from - each line before returning it - skip_blanks [default: true} - skip lines that are empty *after* stripping comments and - whitespace. (If both lstrip_ws and rstrip_ws are false, - then some lines may consist of solely whitespace: these will - *not* be skipped, even if 'skip_blanks' is true.) - join_lines [default: false] - if a backslash is the last non-newline character on a line - after stripping comments and whitespace, join the following line - to it to form one "logical line"; if N consecutive lines end - with a backslash, then N+1 physical lines will be joined to - form one logical line. - collapse_join [default: false] - strip leading whitespace from lines that are joined to their - predecessor; only matters if (join_lines and not lstrip_ws) - errors [default: 'strict'] - error handler used to decode the file content - - Note that since 'rstrip_ws' can strip the trailing newline, the - semantics of 'readline()' must differ from those of the builtin file - object's 'readline()' method! In particular, 'readline()' returns - None for end-of-file: an empty string might just be a blank line (or - an all-whitespace line), if 'rstrip_ws' is true but 'skip_blanks' is - not.""" - - default_options = { 'strip_comments': 1, - 'skip_blanks': 1, - 'lstrip_ws': 0, - 'rstrip_ws': 1, - 'join_lines': 0, - 'collapse_join': 0, - 'errors': 'strict', - } - - def __init__(self, filename=None, file=None, **options): - """Construct a new TextFile object. At least one of 'filename' - (a string) and 'file' (a file-like object) must be supplied. - They keyword argument options are described above and affect - the values returned by 'readline()'.""" - if filename is None and file is None: - raise RuntimeError("you must supply either or both of 'filename' and 'file'") - - # set values for all options -- either from client option hash - # or fallback to default_options - for opt in self.default_options.keys(): - if opt in options: - setattr(self, opt, options[opt]) - else: - setattr(self, opt, self.default_options[opt]) - - # sanity check client option hash - for opt in options.keys(): - if opt not in self.default_options: - raise KeyError("invalid TextFile option '%s'" % opt) - - if file is None: - self.open(filename) - else: - self.filename = filename - self.file = file - self.current_line = 0 # assuming that file is at BOF! - - # '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): - """Open a new file named 'filename'. This overrides both the - 'filename' and 'file' arguments to the constructor.""" - self.filename = filename - self.file = io.open(self.filename, 'r', errors=self.errors) - self.current_line = 0 - - def close(self): - """Close the current file and forget everything we know about it - (filename, current line number).""" - file = self.file - self.file = None - self.filename = None - self.current_line = None - file.close() - - def gen_error(self, msg, line=None): - outmsg = [] - if line is None: - line = self.current_line - outmsg.append(self.filename + ", ") - if isinstance(line, (list, tuple)): - outmsg.append("lines %d-%d: " % tuple(line)) - else: - outmsg.append("line %d: " % line) - outmsg.append(str(msg)) - return "".join(outmsg) - - def error(self, msg, line=None): - raise ValueError("error: " + self.gen_error(msg, line)) - - def warn(self, msg, line=None): - """Print (to stderr) a warning message tied to the current logical - line in the current file. If the current logical line in the - file spans multiple physical lines, the warning refers to the - whole range, eg. "lines 3-5". If 'line' supplied, it overrides - the current line number; it may be a list or tuple to indicate a - range of physical lines, or an integer for a single physical - line.""" - sys.stderr.write("warning: " + self.gen_error(msg, line) + "\n") - - def readline(self): - """Read and return a single logical line from the current file (or - from an internal buffer if lines have previously been "unread" - with 'unreadline()'). If the 'join_lines' option is true, this - may involve reading multiple physical lines concatenated into a - single string. Updates the current line number, so calling - 'warn()' after 'readline()' emits a warning about the physical - line(s) just read. Returns None on end-of-file, since the empty - string can occur if 'rstrip_ws' is true but 'strip_blanks' is - not.""" - # 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 True: - # read the line, make it None if EOF - line = self.file.readline() - if line == '': - line = None - - if self.strip_comments and line: - - # Look for the first "#" in the line. If none, never - # mind. If we find one and it's the first character, or - # is not preceded by "\", then it starts a comment -- - # strip the comment, strip whitespace before it, and - # carry on. Otherwise, it's just an escaped "#", so - # unescape it (and any other escaped "#"'s that might be - # lurking in there) and otherwise leave the line alone. - - pos = line.find("#") - if pos == -1: # no "#" -- no comments - pass - - # It's definitely a comment -- either "#" is the first - # character, or it's elsewhere and unescaped. - elif pos == 0 or line[pos-1] != "\\": - # Have to preserve the trailing newline, because it's - # the job of a later step (rstrip_ws) to remove it -- - # and if rstrip_ws is false, we'd better preserve it! - # (NB. this means that if the final line is all comment - # and has no trailing newline, we will think that it's - # EOF; I think that's OK.) - eol = (line[-1] == '\n') and '\n' or '' - line = line[0:pos] + eol - - # If all that's left is whitespace, then skip line - # *now*, before we try to join it to 'buildup_line' -- - # that way constructs like - # hello \\ - # # comment that should be ignored - # there - # result in "hello there". - if line.strip() == "": - continue - else: # it's an escaped "#" - line = line.replace("\\#", "#") - - # did previous line end with a backslash? then accumulate - if self.join_lines and buildup_line: - # oops: end of file - if line is None: - self.warn("continuation line immediately precedes " - "end-of-file") - return buildup_line - - if self.collapse_join: - line = line.lstrip() - line = buildup_line + line - - # careful: pay attention to line number when incrementing it - if isinstance(self.current_line, list): - self.current_line[1] = self.current_line[1] + 1 - else: - self.current_line = [self.current_line, - self.current_line + 1] - # just an ordinary line, read it as usual - else: - if line is None: # eof - return None - - # still have to be careful about incrementing the line number! - if isinstance(self.current_line, list): - 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) - if self.lstrip_ws and self.rstrip_ws: - line = line.strip() - elif self.lstrip_ws: - line = line.lstrip() - elif self.rstrip_ws: - line = line.rstrip() - - # blank line (whether we rstrip'ed or not)? skip to next line - # if appropriate - if (line == '' or line == '\n') and self.skip_blanks: - continue - - if self.join_lines: - if line[-1] == '\\': - buildup_line = line[:-1] - continue - - if line[-2:] == '\\\n': - buildup_line = line[0:-2] + '\n' - continue - - # well, I guess there's some actual content there: return it - return line - - def readlines(self): - """Read and return the list of all logical lines remaining in the - current file.""" - lines = [] - while True: - line = self.readline() - if line is None: - return lines - lines.append(line) - - def unreadline(self, line): - """Push 'line' (a string) onto an internal buffer that will be - checked by future 'readline()' calls. Handy for implementing - a parser with line-at-a-time lookahead.""" - self.linebuf.append(line) |