From 1c580ae5ae23e64bfffd7597a8336d26017765cb Mon Sep 17 00:00:00 2001
From: malthe <devnull@localhost>
Date: Tue, 8 Jul 2014 10:48:29 +0200
Subject: Write to temporary file and then rename when using --force.

---
 CHANGES.txt                |  6 ++++++
 wheel/install.py           | 37 ++++++++++++++++++++++++-------------
 wheel/test/test_install.py | 21 +++++++++++----------
 3 files changed, 41 insertions(+), 23 deletions(-)

diff --git a/CHANGES.txt b/CHANGES.txt
index 26754c9..e6beb32 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -1,3 +1,9 @@
+In next release ...
+
+- When force is given, write to temporary file and rename. This is
+  necessary because when a file exists, it may already be in use by a
+  running process.
+
 0.24.0
 ======
 - The python tag used for pure-python packages is now .pyN (major version
diff --git a/wheel/install.py b/wheel/install.py
index 3af6d0c..768fec4 100644
--- a/wheel/install.py
+++ b/wheel/install.py
@@ -335,25 +335,36 @@ class WheelFile(object):
         record_name = self.distinfo_name + '/RECORD'
         for info, (key, target, filename, dest) in name_trans.items():
             name = info.filename
-            source = self.zipfile.open(info)
-            # Skip the RECORD file
-            if name == record_name:
-                continue
             ddir = os.path.dirname(dest)
             if not os.path.isdir(ddir):
                 os.makedirs(ddir)
-            destination = HashingFile(open(dest, 'wb'))
-            if key == 'scripts':
-                hashbang = source.readline()
-                if hashbang.startswith(b'#!python'):
-                    hashbang = b'#!' + exename + binary(os.linesep)
-                destination.write(hashbang)
-            shutil.copyfileobj(source, destination)
+
+            if force:
+                dest = "{0}.tmp".format(dest)
+
+            with self.zipfile.open(info) as source, open(dest, 'wb') as f:
+                destination = HashingFile(f)
+
+                # Skip the RECORD file
+                if name == record_name:
+                    continue
+
+                if key == 'scripts':
+                    hashbang = source.readline()
+                    if hashbang.startswith(b'#!python'):
+                        hashbang = b'#!' + exename + binary(os.linesep)
+                    destination.write(hashbang)
+                shutil.copyfileobj(source, destination)
+
+            if force:
+                tmp = dest
+                dest = dest[:-4]
+                os.rename(tmp, dest)
+
             reldest = os.path.relpath(dest, root)
             reldest.replace(os.sep, '/')
             record_data.append((reldest, destination.digest(), destination.length))
-            destination.close()
-            source.close()
+
             # preserve attributes (especially +x bit for scripts)
             attrs = info.external_attr >> 16
             if attrs:  # tends to be 0 if Windows.
diff --git a/wheel/test/test_install.py b/wheel/test/test_install.py
index ddcddf5..ff76c18 100644
--- a/wheel/test/test_install.py
+++ b/wheel/test/test_install.py
@@ -36,15 +36,16 @@ def test_install():
         for key in ('purelib', 'platlib', 'scripts', 'headers', 'data'):
             locs[key] = os.path.join(tempdir, key)
             os.mkdir(locs[key])
-        whl.install(overrides=locs)
-        assert len(os.listdir(locs['purelib'])) == 0
-        assert check(locs['platlib'], 'hello.pyd')
-        assert check(locs['platlib'], 'hello', 'hello.py')
-        assert check(locs['platlib'], 'hello', '__init__.py')
-        assert check(locs['data'], 'hello.dat')
-        assert check(locs['headers'], 'hello.dat')
-        assert check(locs['scripts'], 'hello.sh')
-        assert check(locs['platlib'], 'test-1.0.dist-info', 'RECORD')
+        for force in (False, True):
+            whl.install(force=force, overrides=locs)
+            assert len(os.listdir(locs['purelib'])) == 0
+            assert check(locs['platlib'], 'hello.pyd')
+            assert check(locs['platlib'], 'hello', 'hello.py')
+            assert check(locs['platlib'], 'hello', '__init__.py')
+            assert check(locs['data'], 'hello.dat')
+            assert check(locs['headers'], 'hello.dat')
+            assert check(locs['scripts'], 'hello.sh')
+            assert check(locs['platlib'], 'test-1.0.dist-info', 'RECORD')
     finally:
         shutil.rmtree(tempdir)
 
@@ -52,4 +53,4 @@ def test_install_tool():
     """Slightly improve coverage of wheel.install"""
     wheel.tool.install([TESTWHEEL], force=True, dry_run=True)
 
-    
\ No newline at end of file
+    
-- 
cgit v1.2.1