Ticket #13201: easy_install_lock.patch

setuptools/command/easy_install.py

@@ -10 +10 @@
 __ http://packages.python.org/distribute/easy_install.html
 
 """
-import sys, os.path, zipimport, shutil, tempfile, zipfile, re, stat, random
+import sys, os.path, zipimport, shutil, tempfile, \
+        zipfile, re, stat, random, fcntl
 from glob import glob
 from setuptools import Command, _dont_write_bytecode
 from setuptools.sandbox import run_setup
@@ -1492 +1493 @@
     def __init__(self, filename, sitedirs=()):
         self.filename = filename; self.sitedirs=map(normalize_path, sitedirs)
         self.basedir = normalize_path(os.path.dirname(self.filename))
-        self._load(); Environment.__init__(self, [], None, None)
-        for path in yield_lines(self.paths):
-            map(self.add, find_distributions(path, True))
+        self.paths = []; self.dist_dict = {}
+        Environment.__init__(self, [], None, None); self._load()
 
     def _load(self):
+        old_paths = list(yield_lines(self.paths))
         self.paths = []
         saw_import = False
         seen = dict.fromkeys(self.sitedirs)
         if os.path.isfile(self.filename):
             f = open(self.filename,'rt')
+            fcntl.flock(f, fcntl.LOCK_SH)
             for line in f:
                 if line.startswith('import'):
                     saw_import = True
@@ -1520 +1522 @@
                     self.dirty = True   # we cleaned up, so we're dirty now :)
                     continue
                 seen[path] = 1
+            fcntl.flock(f, fcntl.LOCK_UN)
             f.close()
 
         if self.paths and not saw_import:
             self.dirty = True   # ensure anything we touch has import wrappers
         while self.paths and not self.paths[-1].strip():
             self.paths.pop()
+        for path in old_paths:
+            if not os.path.exists(path):
+                map(self.remove, self.dist_dict[path])
+            elif path not in self.paths:
+                self.paths.append(path)
+                self.dirty = True
+        new_paths = (path for path in self.paths if path not in old_paths)
+        for path in yield_lines(new_paths):
+            self.dist_dict[path] = find_distributions(path, True)
+            map(self.add, self.dist_dict[path])
 
     def save(self):
         """Write changed .pth file back to disk"""
+        f = open(self.filename,'r+t')
+        fcntl.flock(f, fcntl.LOCK_SH)
+        self._load()
         if not self.dirty:
+            f.close()
+            fcntl.flock(f, fcntl.LOCK_UN)
             return
 
         data = '\n'.join(map(self.make_relative,self.paths))
@@ -1544 +1562 @@
                 " sys.__egginsert = p+len(new)\n"
             ) % data
 
-            if os.path.islink(self.filename):
-                os.unlink(self.filename)
-            f = open(self.filename,'wt')
-            f.write(data); f.close()
+        # overwrite anything extra with whitespace
+        data += ' '*(len(open(self.filename,'rt').read())-len(data))
 
-        elif os.path.exists(self.filename):
-            log.debug("Deleting empty %s", self.filename)
-            os.unlink(self.filename)
+        fcntl.flock(f, fcntl.LOCK_EX)
+        f.write(data)
+        fcntl.flock(f, fcntl.LOCK_UN)
+        f.close()
 
         self.dirty = False
 
@@ -1562 +1579 @@
                 dist.location == os.getcwd() #account for '.' being in PYTHONPATH
                 )):
             self.paths.append(dist.location)
+            self.dist_dict[dist.location] = [dist]
             self.dirty = True
         Environment.add(self,dist)
 
@@ -1569 +1587 @@
         """Remove `dist` from the distribution map"""
         while dist.location in self.paths:
             self.paths.remove(dist.location); self.dirty = True
+        if dist.location in self.dist_paths:
+            self.dist_dict[dist.location] = None
         Environment.remove(self,dist)