Get rid of coverage.py

README.md

@@ -98,8 +98,6 @@ PythonFuzz is a port of [fuzzitdev/jsfuzz](https://github.com/fuzzitdev/jsfuzz)
 which is in turn heavily based on [go-fuzz](https://github.com/dvyukov/go-fuzz) originally developed by [Dmitry Vyukov's](https://twitter.com/dvyukov).
 Which is in turn heavily based on [Michal Zalewski](https://twitter.com/lcamtuf) [AFL](http://lcamtuf.coredump.cx/afl/).
 
-For coverage PythonFuzz is using [coverage](https://coverage.readthedocs.io/en/v4.5.x/) instrumentation and coverage library. 
-
 ## Contributions
 
 Contributions are welcome!:) There are still a lot of things to improve, and tests and features to add. We will slowly post those in the

pythonfuzz/fuzzer.py

@@ -5,11 +5,10 @@
 import psutil
 import hashlib
 import logging
-import coverage
 import functools
 import multiprocessing as mp
 
-from pythonfuzz import corpus
+from pythonfuzz import corpus, tracer
 
 logging.getLogger().addHandler(logging.StreamHandler(sys.stdout))
 logging.getLogger().setLevel(logging.DEBUG)
@@ -23,29 +22,6 @@
     lru_cache = functools32.lru_cache
 
 
-if coverage.version.version_info <= (5, ):
-    # Since we're using an old version of coverage.py,
-    # we're monkey patching it a bit to improve the performances.
-
-    # Using memoization here gives +50% in performances, since this
-    # function triggers a lot of syscalls.
-    # See the benchmarks here:
-    #   - https://github.com/fuzzitdev/pythonfuzz/issues/9
-    @lru_cache(None)
-    def abs_file_cache(path):
-        """Return the absolute normalized form of `path`."""
-        try:
-            path = os.path.realpath(path)
-        except UnicodeError:
-            pass
-        path = os.path.abspath(path)
-        path = coverage.files.actual_path(path)
-        path = coverage.files.unicode_filename(path)
-        return path
-
-    coverage.files.abs_file = abs_file_cache
-
-
 def worker(target, child_conn, close_fd_mask):
     # Silence the fuzzee's noise
     class DummyFile:
@@ -59,8 +35,7 @@ def write(self, x):
     if close_fd_mask & 2:
         sys.stderr = DummyFile()
 
-    cov = coverage.Coverage(branch=True, cover_pylib=True)
-    cov.start()
+    sys.settrace(tracer.trace)
     while True:
         buf = child_conn.recv_bytes()
         try:
@@ -71,11 +46,7 @@ def write(self, x):
             child_conn.send(e)
             break
         else:
-            total_coverage = 0
-            cov_data = cov.get_data()
-            for filename in cov_data._arcs:
-                total_coverage += len(cov_data._arcs[filename])
-            child_conn.send(total_coverage)
+            child_conn.send(tracer.get_coverage())
 
 
 class Fuzzer(object):

pythonfuzz/tracer.py

@@ -0,0 +1,36 @@
+import collections
+import sys
+
+prev_line = 0
+prev_filename = ''
+data = collections.defaultdict(set)
+
+def trace(frame, event, arg):
+    if event != 'line':
+        return trace
+
+    global prev_line
+    global prev_filename
+
+    func_filename = frame.f_code.co_filename
+    func_line_no = frame.f_lineno
+
+    if func_filename != prev_filename:
+        # We need a way to keep track of inter-files transferts,
+        # and since we don't really care about the details of the coverage,
+        # concatenating the two filenames in enough.
+        data[func_filename + prev_filename].add((prev_line, func_line_no))
+    else:
+        data[func_filename].add((prev_line, func_line_no))
+
+    prev_line = func_line_no
+    prev_filename = func_filename
+
+    return trace
+
+
+def get_coverage():
+    ret = 0
+    for value in data.values():
+        ret += len(value)
+    return ret

requirements.txt

@@ -1,4 +1,3 @@
-coverage==4.5.4
 psutil==5.6.3
 numpy==1.16.6; python_version < '3'
 numpy==1.17.3; python_version >= '3'

setup.py

@@ -14,7 +14,6 @@
     url="https://github.com/fuzzitdev/pythonfuzz",
     install_requires=[
         # WARNING: Keep these values in line with those in requirements.txt
-        "coverage==4.5.4",
         "psutil==5.6.3",
         "numpy==1.16.6; python_version < '3'",
         "numpy==1.17.3; python_version >= '3'",