Add python coverage module to third_party

third_party/pycoverage/coverage/misc.py

Index: third_party/pycoverage/coverage/misc.py
diff --git a/third_party/pycoverage/coverage/misc.py b/third_party/pycoverage/coverage/misc.py
new file mode 100644
index 0000000000000000000000000000000000000000..0378173fcc3ddc92d00ca94d88d7ef3fec746a25
--- /dev/null
+++ b/third_party/pycoverage/coverage/misc.py
@@ -0,0 +1,167 @@
+"""Miscellaneous stuff for Coverage."""
+
+import errno
+import inspect
+import os
+import sys
+
+from coverage.backward import md5, sorted       # pylint: disable=W0622
+from coverage.backward import string_class, to_bytes
+
+
+def nice_pair(pair):
+    """Make a nice string representation of a pair of numbers.
+
+    If the numbers are equal, just return the number, otherwise return the pair
+    with a dash between them, indicating the range.
+
+    """
+    start, end = pair
+    if start == end:
+        return "%d" % start
+    else:
+        return "%d-%d" % (start, end)
+
+
+def format_lines(statements, lines):
+    """Nicely format a list of line numbers.
+
+    Format a list of line numbers for printing by coalescing groups of lines as
+    long as the lines represent consecutive statements.  This will coalesce
+    even if there are gaps between statements.
+
+    For example, if `statements` is [1,2,3,4,5,10,11,12,13,14] and
+    `lines` is [1,2,5,10,11,13,14] then the result will be "1-2, 5-11, 13-14".
+
+    """
+    pairs = []
+    i = 0
+    j = 0
+    start = None
+    statements = sorted(statements)
+    lines = sorted(lines)
+    while i < len(statements) and j < len(lines):
+        if statements[i] == lines[j]:
+            if start == None:
+                start = lines[j]
+            end = lines[j]
+            j += 1
+        elif start:
+            pairs.append((start, end))
+            start = None
+        i += 1
+    if start:
+        pairs.append((start, end))
+    ret = ', '.join(map(nice_pair, pairs))
+    return ret
+
+
+def short_stack():
+    """Return a string summarizing the call stack."""
+    stack = inspect.stack()[:0:-1]
+    return "\n".join(["%30s : %s @%d" % (t[3],t[1],t[2]) for t in stack])
+
+
+def expensive(fn):
+    """A decorator to cache the result of an expensive operation.
+
+    Only applies to methods with no arguments.
+
+    """
+    attr = "_cache_" + fn.__name__
+    def _wrapped(self):
+        """Inner fn that checks the cache."""
+        if not hasattr(self, attr):
+            setattr(self, attr, fn(self))
+        return getattr(self, attr)
+    return _wrapped
+
+
+def bool_or_none(b):
+    """Return bool(b), but preserve None."""
+    if b is None:
+        return None
+    else:
+        return bool(b)
+
+
+def join_regex(regexes):
+    """Combine a list of regexes into one that matches any of them."""
+    if len(regexes) > 1:
+        return "|".join(["(%s)" % r for r in regexes])
+    elif regexes:
+        return regexes[0]
+    else:
+        return ""
+
+
+def file_be_gone(path):
+    """Remove a file, and don't get annoyed if it doesn't exist."""
+    try:
+        os.remove(path)
+    except OSError:
+        _, e, _ = sys.exc_info()
+        if e.errno != errno.ENOENT:
+            raise
+
+
+class Hasher(object):
+    """Hashes Python data into md5."""
+    def __init__(self):
+        self.md5 = md5()
+
+    def update(self, v):
+        """Add `v` to the hash, recursively if needed."""
+        self.md5.update(to_bytes(str(type(v))))
+        if isinstance(v, string_class):
+            self.md5.update(to_bytes(v))
+        elif v is None:
+            pass
+        elif isinstance(v, (int, float)):
+            self.md5.update(to_bytes(str(v)))
+        elif isinstance(v, (tuple, list)):
+            for e in v:
+                self.update(e)
+        elif isinstance(v, dict):
+            keys = v.keys()
+            for k in sorted(keys):
+                self.update(k)
+                self.update(v[k])
+        else:
+            for k in dir(v):
+                if k.startswith('__'):
+                    continue
+                a = getattr(v, k)
+                if inspect.isroutine(a):
+                    continue
+                self.update(k)
+                self.update(a)
+
+    def digest(self):
+        """Retrieve the digest of the hash."""
+        return self.md5.digest()
+
+
+class CoverageException(Exception):
+    """An exception specific to Coverage."""
+    pass
+
+class NoSource(CoverageException):
+    """We couldn't find the source for a module."""
+    pass
+
+class NoCode(NoSource):
+    """We couldn't find any code at all."""
+    pass
+
+class NotPython(CoverageException):
+    """A source file turned out not to be parsable Python."""
+    pass
+
+class ExceptionDuringRun(CoverageException):
+    """An exception happened while running customer code.
+
+    Construct it with three arguments, the values from `sys.exc_info`.
+
+    """
+    pass