Infrastructure for dependency rules.

1 files changed, 31 insertions, 9 deletions

diff --git a/deheader b/deheader
index 243b868..3a05778 100755
--- a/deheader
+++ b/deheader
@@ -34,6 +34,16 @@ COMMAND_DEBUG  = 3
 
 version = "0.2"
 
+# Difference in various compiler implementations and OSes mean that for cross-
+# platform compatibility you sometimes wabt to leave "unneeded" headers alone
+# because they're required in order to satify dependencies on other platforms.
+# We list those here.  Home port is Linux; these are mostly extracted from
+# observing compiles on BSD systems.
+requirements = map(lambda (r, h): (re.compile(r), h), (
+    (r"umask\s*\(",     ["<sys/stat.h>", "<sys/types.h>"]),
+    (r"<sys/socket.h>", ["<sys/stat.h>"]),
+    ))
+
 class Baton:
     "Ship progress indications to stderr."
     def __init__(self, prompt, endmsg=None):
@@ -91,8 +101,10 @@ class InclusionMap:
                         if InclusionMap.c_source(path):
                             self.files.append(path)
         self.depends_on = {}
+        self.requires = {}
         for sourcefile in self.files:
             includes = []
+            requires = []
             ifdepth = 0
             for line in open(sourcefile):
                 if line.startswith("#if") or line.startswith("#ifndef"):
@@ -111,7 +123,11 @@ class InclusionMap:
                         includes.append(line)
                     elif verbose > 1:
                         print "deheader: ignoring %s (conditional inclusion)" % name
+                    for (r, h) in requirements:
+                        if r.search(line):
+                            requires += line
             self.depends_on[sourcefile] = includes
+            self.requires[sourcefile] = requires
     def forget(self, sourcefile, header):
         "Forget a header dependency."
         self.depends_on[sourcefile].remove(header)
@@ -125,11 +141,11 @@ class SaveForModification:
         self.filename = filename
         self.original = filename + "-orig"
         os.rename(self.filename, self.original)
-    def remove_headers(self, headers):
+    def remove_headers(self, removables):
         "Prepare a version with specified headers deleted."
         ofp = open(self.filename, "w")
         for line in open(self.original):
-            if line not in headers:
+            if line not in removables:
                 ofp.write(line)
         ofp.close()
     def forget(self):
@@ -177,7 +193,7 @@ def testcompile(source, maker, msg="", verbosity=0):
           % (sourcefile, msg, explain, end-start)
     return (status, end - start)
 
-def c_analyze(sourcefile, maker, includes, verbosity):
+def c_analyze(sourcefile, maker, includes, requires, verbosity):
     "Given a C file and a list of includes, return those that can be omitted."
     # We'll remove headers in reverse order, because later unnecessary
     # headers might depend on earlier ones
@@ -190,14 +206,16 @@ def c_analyze(sourcefile, maker, includes, verbosity):
         while True:                
             keepgoing = False
             for header in includes:
+                if verbosity == BATON_DEBUG:
+                    baton.twirl()
+                if header in requires:
+                    continue
                 saveit.remove_headers([header])
                 (st, t) = testcompile(sourcefile, maker, " without %s" % trim(header), verbosity)
                 if st == 0:
                     unneeded.append(header)
                     includes.remove(header)
                     keepgoing = True
-                if verbosity == BATON_DEBUG:
-                    baton.twirl()
             if not keepgoing:
                 break
     finally:
@@ -206,20 +224,21 @@ def c_analyze(sourcefile, maker, includes, verbosity):
             baton.end()
     return unneeded
 
-def deheader(sourcefile, maker, includes, remove, verbose):
+def deheader(sourcefile, maker, includes, requires, remove, verbose):
     # Sanity check against broken sourcefiles; we want this to
     # complain visibly if the sourcefile won't build at all.
     (st, t) = testcompile(sourcefile, maker, min(1, verbose))
     if st == 0:
         # Now do the analysis
         if sourcefile.endswith(".c") or sourcefile.endswith(".cpp"):
-            unneeded = c_analyze(sourcefile, maker, includes[:], verbose)
+            unneeded = c_analyze(sourcefile, maker,
+                                 includes[:], requires[:], verbose)
         if unneeded:
             for line in unneeded:
                 print "deheader: remove %s from %s" % (trim(line), sourcefile)
             if remove:
                 remove_it = SaveForModification(sourcefile)
-                remove_it.remove_headers(unneeded)
+                remove_it.remove_headers(unneeded, requires)
                 remove_it.forget()
                 del remove_it
         return Summary([sourcefile], includes, unneeded)
@@ -277,7 +296,10 @@ if __name__ == "__main__":
     inclusion_map = InclusionMap(arguments, ignore, verbose)
     summaries = []
     for sourcefile in inclusion_map.depends_on:
-        summaries.append(deheader(sourcefile, maker, inclusion_map.depends_on[sourcefile], remove, verbose))
+        summaries.append(deheader(sourcefile, maker,
+                                  inclusion_map.depends_on[sourcefile],
+                                  inclusion_map.requires[sourcefile],
+                                  remove, verbose))
     stats = Summary()
     for summary in summaries:
         stats = stats + summary