Project

General

Profile

1 1630 aaronmk
# I/O
2
3 4917 aaronmk
import operator
4 1673 aaronmk
import timeouts
5 1635 aaronmk
6 1928 aaronmk
##### Exceptions
7
8
class InputStreamsOnlyException(Exception):
9
    def __init__(self): Exception.__init__(self, 'Only input streams allowed')
10
11 1759 aaronmk
##### Wrapped streams
12
13 1635 aaronmk
class WrapStream:
14
    '''Forwards close() to the underlying stream'''
15
    def __init__(self, stream): self.stream = stream
16
17
    def close(self): self.stream.close()
18
19 1759 aaronmk
##### Line iteration
20
21 1635 aaronmk
class StreamIter(WrapStream):
22 1630 aaronmk
    '''Iterates over the lines in a stream.
23
    Unlike stream.__iter__(), doesn't wait for EOF to start returning lines.
24
    Offers curr() method.
25
    '''
26
    def __init__(self, stream):
27 1635 aaronmk
        WrapStream.__init__(self, stream)
28 1630 aaronmk
        self.line = None
29
30
    def __iter__(self): return self
31
32
    def curr(self):
33 1964 aaronmk
        if self.line == None: self.line = self.readline()
34 1630 aaronmk
        if self.line == '': raise StopIteration
35
        return self.line
36
37
    def next(self):
38
        line = self.curr()
39
        self.line = None
40
        return line
41 1964 aaronmk
42
    # Define as a separate method so it can be overridden
43
    def readline(self): return self.stream.readline()
44 1635 aaronmk
45 1686 aaronmk
def copy(from_, to):
46
    for line in StreamIter(from_): to.write(line)
47
48 1759 aaronmk
def consume(in_):
49
    for line in StreamIter(in_): pass
50
51 4917 aaronmk
def read_all(stream): return reduce(operator.add, StreamIter(stream), '')
52
53 13463 aaronmk
def file_get_contents(file_path): return read_all(open(file_path))
54
55 1759 aaronmk
##### Timeouts
56
57 1635 aaronmk
class TimeoutInputStream(WrapStream):
58 1673 aaronmk
    '''@param timeout sec'''
59
    def __init__(self, stream, timeout):
60 1635 aaronmk
        WrapStream.__init__(self, stream)
61 1673 aaronmk
        self.timeout = timeout
62 1630 aaronmk
63 1635 aaronmk
    def readline(self):
64 1673 aaronmk
        return timeouts.run(lambda: self.stream.readline(), self.timeout)
65 1928 aaronmk
66
    def write(self, str_): raise InputStreamsOnlyException()
67 1630 aaronmk
68 1710 aaronmk
##### Filtered/traced streams
69 1686 aaronmk
70 1962 aaronmk
class FilterStream(StreamIter):
71 1710 aaronmk
    '''Wraps a stream, filtering each string read or written'''
72
    def __init__(self, filter_, stream):
73 1962 aaronmk
        StreamIter.__init__(self, stream)
74 1710 aaronmk
        self.filter = filter_
75 1630 aaronmk
76 1964 aaronmk
    def readline(self): return self.filter(StreamIter.readline(self))
77 1682 aaronmk
78 1762 aaronmk
    def read(self, n): return self.readline() # forward all reads to readline()
79
80 1710 aaronmk
    def write(self, str_): return self.stream.write(self.filter(str_))
81 1630 aaronmk
82 1710 aaronmk
class TracedStream(FilterStream):
83
    '''Wraps a stream, running a trace function on each string read or written
84
    '''
85
    def __init__(self, trace, stream):
86
        def filter_(str_):
87
            trace(str_)
88
            return str_
89
        FilterStream.__init__(self, filter_, stream)
90
91 1684 aaronmk
class LineCountStream(TracedStream):
92
    '''Wraps a unidirectional stream, making the current line number available.
93 5592 aaronmk
    Lines start counting from 1, incrementing before each line is returned.'''
94 1630 aaronmk
    def __init__(self, stream):
95 5592 aaronmk
        self.line_num = 0
96 1630 aaronmk
        def trace(str_): self.line_num += str_.count('\n')
97 1682 aaronmk
        TracedStream.__init__(self, trace, stream)
98
99 1928 aaronmk
class LineCountInputStream(TracedStream):
100
    '''Wraps an input stream, making the current line number available.
101 5592 aaronmk
    Lines start counting from 1, incrementing before each line is returned.
102 1928 aaronmk
    This is faster than LineCountStream for input streams, because all reading
103
    is done through readline() so newlines don't need to be explicitly counted.
104
    '''
105
    def __init__(self, stream):
106 5592 aaronmk
        self.line_num = 0
107 2672 aaronmk
        def trace(str_):
108
            if str_ != '': self.line_num += 1 # EOF is not a line
109 1928 aaronmk
        TracedStream.__init__(self, trace, stream)
110
111
    def write(self, str_): raise InputStreamsOnlyException()
112
113 1939 aaronmk
class ProgressInputStream(TracedStream):
114
    '''Wraps an input stream, reporting the # lines read every n lines and after
115
    the last line is read.
116
    @param log The output stream for progress messages
117
    '''
118
    def __init__(self, stream, log, msg='Read %d line(s)', n=100):
119
        self.eof = False
120
121
        def trace(str_):
122
            msg_ = msg # may be modified, so can't have same name as outer var
123
            if str_ == None: # closed
124
                if self.eof: return # not closed prematurely
125
                str_ = '' # closed prematurely, so signal EOF
126
                msg_ += ' (not all input read)'
127
128
            self.eof = eof = str_ == ''
129
            if eof: line_ending = '\n'
130
            else: line_ending = '\r'
131
132 5592 aaronmk
            line_ct = self.stream.line_num
133
            if eof or (line_ct > 0 and line_ct % n == 0):
134
                log.write((msg_ % line_ct)+line_ending)
135 1939 aaronmk
        self.trace = trace
136
137
        TracedStream.__init__(self, trace, LineCountInputStream(stream))
138
139
    def close(self):
140
        self.trace(None) # signal closed
141
        TracedStream.close(self)
142
143 1682 aaronmk
class CaptureStream(TracedStream):
144
    '''Wraps a stream, capturing matching text.
145 1706 aaronmk
    Matches can be retrieved from self.matches.'''
146 1682 aaronmk
    def __init__(self, stream, start_str, end_str):
147
        self.recording = False
148 1706 aaronmk
        self.matches = []
149 1682 aaronmk
150
        def trace(str_):
151 1707 aaronmk
            start_idx = 0
152
            if not self.recording:
153
                start_idx = str_.find(start_str)
154
                if start_idx >= 0:
155
                    self.recording = True
156
                    self.matches.append('')
157
            if self.recording:
158
                end_idx = str_.find(end_str)
159
                if end_idx >= 0:
160
                    self.recording = False
161
                    end_idx += len(end_str)
162
                else: end_idx = len(str_)
163
164
                self.matches[-1] += str_[start_idx:end_idx]
165 1682 aaronmk
166
        TracedStream.__init__(self, trace, stream)