improve behaviour

5 files changed, 73 insertions, 19 deletions

diff --git a/src/engine/SCons/CacheDir.py b/src/engine/SCons/CacheDir.py
index be0163d..728871f 100644
--- a/src/engine/SCons/CacheDir.py
+++ b/src/engine/SCons/CacheDir.py
@@ -27,7 +27,10 @@ __doc__ = """
 CacheDir support
 """
 
-import os.path
+from collections import defaultdict
+
+import json
+import os
 import stat
 import sys
 
@@ -72,7 +75,8 @@ CacheRetrieve = SCons.Action.Action(CacheRetrieveFunc, CacheRetrieveString)
 CacheRetrieveSilent = SCons.Action.Action(CacheRetrieveFunc, None)
 
 def CachePushFunc(target, source, env):
-    if cache_readonly: return
+    if cache_readonly:
+        return
 
     t = target[0]
     if t.nocache:
@@ -133,11 +137,36 @@ class CacheDir(object):
         except ImportError:
             msg = "No hashlib or MD5 module available, CacheDir() not supported"
             SCons.Warnings.warn(SCons.Warnings.NoMD5ModuleWarning, msg)
-            self.path = None
-        else:
-            self.path = path
+            path = None
+        self.path = path
         self.current_cache_debug = None
         self.debugFP = None
+        self.config = defaultdict()
+        if path is None:
+            return
+        # See if there's a config file in the cache directory
+        config_file = os.path.join(path, 'config')
+        if not os.path.exists(config_file):
+            # If the directory exists we're likely version 1, otherwise
+            # assume we're latest.
+            # A note: There is a race hazard here, if two processes start and
+            # attempt to create the cache directory at the same time. However,
+            # python doesn't really give you the option to do exclusive file
+            # creation (it doesn't even give you the option to error on opening
+            # an existing file for writing...). The ordering of events here
+            # as an attempt to alleviate this, on the basis that it's a pretty
+            # unlikely occurence (it'd require two builds with a brand new cache
+            # directory)
+            if os.path.isdir(path):
+                self.config['prefix_len'] = 1
+            else:                
+                os.makedirs(path)
+                self.config['prefix_len'] = 2
+            if not os.path.exists(config_file):
+                with open(config_file, 'w') as config:
+                    self.config = json.dump(self.config, config)
+        with open(config_file) as config:
+            self.config = json.load(config)
 
     def CacheDebug(self, fmt, target, cachefile):
         if cache_debug != self.current_cache_debug:
@@ -152,7 +181,7 @@ class CacheDir(object):
             self.debugFP.write(fmt % (target, os.path.split(cachefile)[1]))
 
     def is_enabled(self):
-        return (cache_enabled and not self.path is None)
+        return cache_enabled and not self.path is None
 
     def is_readonly(self):
         return cache_readonly
@@ -164,7 +193,7 @@ class CacheDir(object):
             return None, None
 
         sig = node.get_cachedir_bsig()
-        subdir = sig[:2].upper()
+        subdir = sig[:self.config['prefix_len']].upper()
         dir = os.path.join(self.path, subdir)
         return dir, os.path.join(dir, sig)
 
diff --git a/src/engine/SCons/CacheDirTests.py b/src/engine/SCons/CacheDirTests.py
index 3b99d41..82fba8f 100644
--- a/src/engine/SCons/CacheDirTests.py
+++ b/src/engine/SCons/CacheDirTests.py
@@ -83,6 +83,11 @@ class BaseTestCase(unittest.TestCase):
             #node.binfo.ninfo.bsig = bsig
         return node
 
+    def tearDown(self):
+        os.remove(os.path.join(self._CacheDir.path, 'config'))
+        os.rmdir(self._CacheDir.path)
+        # Should that be shutil.rmtree?
+
 class CacheDirTestCase(BaseTestCase):
     """
     Test calling CacheDir code directly.
@@ -98,10 +103,12 @@ class CacheDirTestCase(BaseTestCase):
         SCons.Util.MD5collect = my_collect
 
         try:
-            f5 = self.File("cd.f5", 'a_fake_bsig')
+            name = 'a_fake_bsig'
+            f5 = self.File("cd.f5", name)
             result = self._CacheDir.cachepath(f5)
-            dirname = os.path.join('cache', 'A_')
-            filename = os.path.join(dirname, 'a_fake_bsig')
+            len = self._CacheDir.config['prefix_len']
+            dirname = os.path.join('cache', name.upper()[:len])
+            filename = os.path.join(dirname, name)
             assert result == (dirname, filename), result
         finally:
             SCons.Util.MD5collect = save_collect
diff --git a/src/script/scons-rename-cachedirs.py b/src/script/scons-rename-cachedirs.py
index dd76a42..24897d1 100644
--- a/src/script/scons-rename-cachedirs.py
+++ b/src/script/scons-rename-cachedirs.py
@@ -36,6 +36,7 @@ __date__ = "__DATE__"
 __developer__ = "__DEVELOPER__"

 

 import glob

+import json

 import os

 

 # The entire purpose of this script is to rename the files in the specified

@@ -43,20 +44,35 @@ import os
 # directories.

 

 # You run this in the cache directory.

+

 expected = ['{:X}'.format(x) for x in range(0, 16)]

-# check there are 16 directories, 0 - 9, A - F

-if sorted(glob.glob('*')) != [x]:

-    raise RuntimeError("This doesn't look like a cache directory")

+

+if not os.path.exists('config'):    

+    # check there are 16 directories, 0 - 9, A - F

+    if sorted(glob.glob('*')) != expected:

+        raise RuntimeError("This doesn't look like a (version 1) cache directory")

+    config = { 'prefix_len' : 1 }

+else:

+    with open('config') as conf:

+        config = json.load(conf)

+    if config['prefix_len'] != 1:

+        raise RuntimeError("This doesn't look like a (version 1) cache directory")

+

 dirs = set()

 for file in glob.iglob(os.path.join('*', '*')):

     name = os.path.basename(file)

     dir = name[:2].upper()

-    print dir, name

     if dir not in dirs:

         os.mkdir(dir)

         dirs.add(dir)

     os.rename(file, os.path.join(dir, name))

 

- # Now delete the original directories

- for dir in expected:

-    os.rmdir(dir)
\ No newline at end of file
+# Now delete the original directories

+for dir in expected:

+    if os.path.exists(dir):

+        os.rmdir(dir)

+

+# and write a config file

+config['prefix_len'] = 2

+with open('config', 'w') as conf:

+    json.dump(config, conf)
\ No newline at end of file
diff --git a/test/CacheDir/CacheDir.py b/test/CacheDir/CacheDir.py
index 9abe0e0..4c05634 100644
--- a/test/CacheDir/CacheDir.py
+++ b/test/CacheDir/CacheDir.py
@@ -82,7 +82,8 @@ test.must_not_exist(src_aaa_out)
 test.must_not_exist(src_bbb_out)
 test.must_not_exist(src_ccc_out)
 test.must_not_exist(src_all)
-test.fail_test(len(os.listdir(cache)))
+# Even if you do -n, the cache will be configured.
+test.fail_test(os.listdir(cache) != ['config'])
 
 # Verify that a normal build works correctly, and clean up.
 # This should populate the cache with our derived files.
diff --git a/test/CacheDir/environment.py b/test/CacheDir/environment.py
index 4fb9b51..1378bb2 100644
--- a/test/CacheDir/environment.py
+++ b/test/CacheDir/environment.py
@@ -85,7 +85,8 @@ test.must_not_exist(src_aaa_out)
 test.must_not_exist(src_bbb_out)
 test.must_not_exist(src_ccc_out)
 test.must_not_exist(src_all)
-test.fail_test(len(os.listdir(cache)))
+# Even if you do -n, the cache will be configured.
+test.fail_test(os.listdir(cache) != ['config'])
 
 # Verify that a normal build works correctly, and clean up.
 # This should populate the cache with our derived files.