"""Statistics analyzer for HotShot."""

try:
import profile
import pstats
except ImportError, e:
raise ImportError, str(e) + '; please install the python-profiler package'

import hotshot.log

from hotshot.log import ENTER, EXIT


def load(filename):
return StatsLoader(filename).load()


class StatsLoader:
def __init__(self, logfn):
self._logfn = logfn
self._code = {}
self._stack = []
self.pop_frame = self._stack.pop

def load(self):
# The timer selected by the profiler should never be used, so make
# sure it doesn't work:
p = Profile()
p.get_time = _brokentimer
log = hotshot.log.LogReader(self._logfn)
taccum = 0
for event in log:
what, (filename, lineno, funcname), tdelta = event
if tdelta > 0:
taccum += tdelta

# We multiply taccum to convert from the microseconds we
# have to the seconds that the profile/pstats module work
# with; this allows the numbers to have some basis in
# reality (ignoring calibration issues for now).

if what == ENTER:
frame = self.new_frame(filename, lineno, funcname)
p.trace_dispatch_call(frame, taccum * .000001)
taccum = 0

elif what == EXIT:
frame = self.pop_frame()
p.trace_dispatch_return(frame, taccum * .000001)
taccum = 0

# no further work for line events

assert not self._stack
return pstats.Stats(p)

def new_frame(self, *args):
# args must be filename, firstlineno, funcname
# our code objects are cached since we don't need to create
# new ones every time
try:
code = self._code[args]
except KeyError:
code = FakeCode(*args)
self._code[args] = code
# frame objects are create fresh, since the back pointer will
# vary considerably
if self._stack:
back = self._stack[-1]
else:
back = None
frame = FakeFrame(code, back)
self._stack.append(frame)
return frame


class Profile(profile.Profile):
def simulate_cmd_complete(self):
pass


class FakeCode:
def __init__(self, filename, firstlineno, funcname):
self.co_filename = filename
self.co_firstlineno = firstlineno
self.co_name = self.__name__ = funcname


class FakeFrame:
def __init__(self, code, back):
self.f_back = back
self.f_code = code


def _brokentimer():
raise RuntimeError, "this timer should not be called"