Implement PEP 235: Import on Case-Insensitive Platforms.

    http://python.sourceforge.net/peps/pep-0235.html

Renamed check_case to case_ok.  Substantial code rearrangement to get
this stuff in one place in the file.  Innermost loop of find_module()
now much simpler and #ifdef-free, and I want to keep it that way (it's
bad enough that the innermost loop is itself still in an #ifdef!).

Windows semantics tested and are fine.

Jason, Cygwin *should* be fine if and only if what you did before "worked"
for case_ok.

Jack, the semantics on your flavor of Mac have definitely changed (see
the PEP), and need to be tested.  The intent is that your flavor of Mac
now work the same as everything else in the "lower left" box, including
respecting PYTHONCASEOK.

Steven, sorry, you did the most work here so far but you got screwed the
worst.  Happy to work with you on repairing it, but I don't understand
anything about all your Mac variants.  We need to add another branch (or
two, three, ...?) inside case_ok.  But we should not need to change
anything else.

1 files changed, 87 insertions, 138 deletions

diff --git a/Python/import.c b/Python/import.c
index b0069e4..52b8074 100644
--- a/Python/import.c
+++ b/Python/import.c
@@ -633,7 +633,7 @@ open_exclusive(char *filename)
 #ifdef O_BINARY
 				|O_BINARY   /* necessary for Windows */
 #endif
-		
+
 			, 0666);
 	if (fd < 0)
 		return NULL;
@@ -830,13 +830,10 @@ extern FILE *PyWin_FindRegisteredModule(const char *, struct filedescr **,
 					char *, int);
 #endif
 
-#ifdef CHECK_IMPORT_CASE
-static int check_case(char *, int, int, char *);
-#endif
-
+static int case_ok(char *, int, int, char *);
 static int find_init_module(char *); /* Forward */
 
-#ifdef HAVE_DIRENT_H
+#if 0 /* XXX was #ifdef HAVE_DIRENT_H; resolve whether we really need this */
 
 static int MatchFilename(char *pathname, char *filename);
 
@@ -944,11 +941,11 @@ find_module(char *realname, PyObject *path, char *buf, size_t buflen,
 			continue; /* v contains '\0' */
 #ifdef macintosh
 #ifdef INTERN_STRINGS
-		/* 
+		/*
 		** Speedup: each sys.path item is interned, and
 		** FindResourceModule remembers which items refer to
 		** folders (so we don't have to bother trying to look
-		** into them for resources). 
+		** into them for resources).
 		*/
 		PyString_InternInPlace(&PyList_GET_ITEM(path, i));
 		v = PyList_GET_ITEM(path, i);
@@ -956,13 +953,13 @@ find_module(char *realname, PyObject *path, char *buf, size_t buflen,
 		if (PyMac_FindResourceModule((PyStringObject *)v, name, buf)) {
 			static struct filedescr resfiledescr =
 				{"", "", PY_RESOURCE};
-			
+
 			return &resfiledescr;
 		}
 		if (PyMac_FindCodeResourceModule((PyStringObject *)v, name, buf)) {
 			static struct filedescr resfiledescr =
 				{"", "", PY_CODERESOURCE};
-			
+
 			return &resfiledescr;
 		}
 #endif
@@ -974,18 +971,17 @@ find_module(char *realname, PyObject *path, char *buf, size_t buflen,
 			buf[len++] = SEP;
 		strcpy(buf+len, name);
 		len += namelen;
+
+		/* Check for package import (buf holds a directory name,
+		   and there's an __init__ module in that directory */
 #ifdef HAVE_STAT
-		if (stat(buf, &statbuf) == 0) {
-			if (S_ISDIR(statbuf.st_mode)) {
-				if (find_init_module(buf)) {
-#ifdef CHECK_IMPORT_CASE
-					if (!check_case(buf, len, namelen,
-							name))
-						return NULL;
-#endif
-					return &fd_package;
-				}
-			}
+		if (stat(buf, &statbuf) == 0 &&
+		    S_ISDIR(statbuf.st_mode) &&
+		    find_init_module(buf)) {
+			if (case_ok(buf, len, namelen, name))
+				return &fd_package;
+			else
+				return NULL;
 		}
 #else
 		/* XXX How are you going to test for directories? */
@@ -1000,27 +996,14 @@ find_module(char *realname, PyObject *path, char *buf, size_t buflen,
 			if (Py_VerboseFlag > 1)
 				PySys_WriteStderr("# trying %s\n", buf);
 			fp = fopen(buf, fdp->mode);
-#ifdef HAVE_DIRENT_H
-
-		        if (fp != NULL) {  /* check case */
-				char *curpath = PyString_AsString(v);
-				char *nstart = buf + strlen(curpath);
-				if (*nstart == SEP)
-					nstart++; 
-				if (MatchFilename(curpath, nstart)) {
-					break;      /* Found */
+			if (fp != NULL) {
+				if (case_ok(buf, len, namelen, name))
+					break;
+				else {	 /* continue search */
+					fclose(fp);
+					fp = NULL;
 				}
-				fclose(fp); /* No. Close & continue search */
-				fp = NULL;
-				if (Py_VerboseFlag > 1)
-					PySys_WriteStderr(
-					      "# case mismatch for %s:  %s\n", 
-					      name, buf);
 			}
-#else  /* !HAVE_DIRENT_H */
-			if (fp != NULL)
-				break;
-#endif /* HAVE_DIRENT_H */
 		}
 #endif /* !macintosh */
 		if (fp != NULL)
@@ -1031,62 +1014,62 @@ find_module(char *realname, PyObject *path, char *buf, size_t buflen,
 			     "No module named %.200s", name);
 		return NULL;
 	}
-#ifdef CHECK_IMPORT_CASE
-	if (!check_case(buf, len, namelen, name)) {
-		fclose(fp);
-		return NULL;
-	}
-#endif
-
 	*p_fp = fp;
 	return fdp;
 }
 
-#ifdef CHECK_IMPORT_CASE
-
+/* case_ok(buf, len, namelen, name)
+ * We've already done a successful stat() or fopen() on buf (a path of length
+ * len; can not assume there's a trailing null).  name is the last component
+ * of then path (a string of length namelen, exclusive of trailing null).
+ * case_ok() is to return 1 if there's a case-sensitive match for
+ * name, else 0.  case_ok() is also to return 1 if envar PYTHONCASEOK
+ * exists.
+ * case_ok() is used to implement case-sensitive import semantics even
+ * on platforms with case-insensitive filesystems.  It's trivial to implement
+ * for case-sensitive filesystems.  It's pretty much a cross-platform
+ * nightmare for systems with case-insensitive filesystems.
+ */
+
+/* First we may need a pile of platform-specific header files; the sequence
+ * of #if's here should match the sequence in the body of case_ok().
+ */
 #if defined(MS_WIN32) || defined(__CYGWIN__)
 #include <windows.h>
 #include <ctype.h>
-
-static int
-allcaps8x3(char *s)
-{
-	/* Return 1 if s is an 8.3 filename in ALLCAPS */
-	char c;
-	char *dot = strchr(s, '.');
-	char *end = strchr(s, '\0');
-	if (dot != NULL) {
-		if (dot-s > 8)
-			return 0; /* More than 8 before '.' */
-		if (end-dot > 4)
-			return 0; /* More than 3 after '.' */
-		end = strchr(dot+1, '.');
-		if (end != NULL)
-			return 0; /* More than one dot  */
-	}
-	else if (end-s > 8)
-		return 0; /* More than 8 and no dot */
-	while ((c = *s++)) {
-		if (islower(c))
-			return 0;
-	}
-	return 1;
-}
-
 #ifdef __CYGWIN__
 #include <sys/cygwin.h>
 #endif
 
+#elif defined(DJGPP)
+#include <dir.h>
+
+#elif defined(macintosh)
+#include <TextUtils.h>
+#ifdef USE_GUSI1
+#include "TFileSpec.h"		/* for Path2FSSpec() */
+#endif
+
+#endif
+
 static int
-check_case(char *buf, int len, int namelen, char *name)
+case_ok(char *buf, int len, int namelen, char *name)
 {
+/* Pick a platform-specific implementation; the sequence of #if's here should
+ * match the sequence just above.
+ */
+
+/* MS_WIN32 || __CYGWIN__ */
+#if defined(MS_WIN32) || defined(__CYGWIN__)
 	WIN32_FIND_DATA data;
 	HANDLE h;
 #ifdef __CYGWIN__
 	char tempbuf[MAX_PATH];
 #endif
+
 	if (getenv("PYTHONCASEOK") != NULL)
 		return 1;
+
 #ifdef __CYGWIN__
 	cygwin32_conv_to_win32_path(buf, tempbuf);
 	h = FindFirstFile(tempbuf, &data);
@@ -1100,35 +1083,33 @@ check_case(char *buf, int len, int namelen, char *name)
 		return 0;
 	}
 	FindClose(h);
-	if (allcaps8x3(data.cFileName)) {
-		/* Skip the test if the filename is ALL.CAPS.  This can
-		   happen in certain circumstances beyond our control,
-		   e.g. when software is installed under NT on a FAT
-		   filesystem and then the same FAT filesystem is used
-		   under Windows 95. */
+	return strncmp(data.cFileName, name, namelen) == 0;
+
+/* DJGPP */
+#elif defined(DJGPP)
+	struct ffblk ffblk;
+	int done;
+
+	if (getenv("PYTHONCASEOK") != NULL)
 		return 1;
-	}
-	if (strncmp(data.cFileName, name, namelen) != 0) {
-		strcpy(buf+len-namelen, data.cFileName);
+
+	done = findfirst(buf, &ffblk, FA_ARCH|FA_RDONLY|FA_HIDDEN|FA_DIREC);
+	if (done) {
 		PyErr_Format(PyExc_NameError,
-		  "Case mismatch for module name %.100s\n(filename %.300s)",
+		  "Can't find file for module %.100s\n(filename %.300s)",
 		  name, buf);
 		return 0;
 	}
-	return 1;
-}
-#endif /* MS_WIN32 */
+	return strncmp(ffblk.ff_name, name, namelen) == 0;
 
-#ifdef macintosh
-#include <TextUtils.h>
-#ifdef USE_GUSI1
-#include "TFileSpec.h"		/* for Path2FSSpec() */
-#endif
-static int
-check_case(char *buf, int len, int namelen, char *name)
-{
+/* macintosh */
+#elif defined(macintosh)
 	FSSpec fss;
 	OSErr err;
+
+	if (getenv("PYTHONCASEOK") != NULL)
+		return 1;
+
 #ifndef USE_GUSI1
 	err = FSMakeFSSpec(0, 0, Pstring(buf), &fss);
 #else
@@ -1154,48 +1135,16 @@ check_case(char *buf, int len, int namelen, char *name)
 		     name, buf);
 		return 0;
 	}
-	if (namelen > fss.name[0] ||
-	    strncmp(name, (char *)fss.name+1, namelen) != 0) {
-		PyErr_Format(PyExc_NameError,
-		     "Case mismatch for module name %.100s\n(filename %.300s)",
-		     name, fss.name);
-		return 0;
-	}
-	return 1;
-}
-#endif /* macintosh */
-
-#ifdef DJGPP
-#include <dir.h>
-
-static int
-check_case(char *buf, int len, int namelen, char *name)
-{
-	struct ffblk ffblk;
-	int done;
-
-	if (getenv("PYTHONCASEOK") != NULL)
-		return 1;
-	done = findfirst(buf, &ffblk, FA_ARCH|FA_RDONLY|FA_HIDDEN|FA_DIREC);
-	if (done) {
-		PyErr_Format(PyExc_NameError,
-		  "Can't find file for module %.100s\n(filename %.300s)",
-		  name, buf);
-		return 0;
-	}
+	return fss.name[0] >= namelen &&
+	       strncmp(name, (char *)fss.name+1, namelen) == 0;
 
-	if (strncmp(ffblk.ff_name, name, namelen) != 0) {
-		strcpy(buf+len-namelen, ffblk.ff_name);
-		PyErr_Format(PyExc_NameError,
-		  "Case mismatch for module name %.100s\n(filename %.300s)",
-		  name, buf);
-		return 0;
-	}
+/* assuming it's a case-sensitive filesystem, so there's nothing to do! */
+#else
 	return 1;
-}
+
 #endif
+}
 
-#endif /* CHECK_IMPORT_CASE */
 
 #ifdef HAVE_STAT
 /* Helper to look for __init__.py or __init__.py[co] in potential package */
@@ -1754,7 +1703,7 @@ import_submodule(PyObject *mod, char *subname, char *fullname)
 	   else: mod.__name__ + "." + subname == fullname
 	*/
 
-	if ((m = PyDict_GetItemString(modules, fullname)) != NULL) { 
+	if ((m = PyDict_GetItemString(modules, fullname)) != NULL) {
 		Py_INCREF(m);
 	}
 	else {
@@ -1929,7 +1878,7 @@ PyImport_Import(PyObject *module_name)
 	Py_XDECREF(globals);
 	Py_XDECREF(builtins);
 	Py_XDECREF(import);
- 
+
 	return r;
 }
 
@@ -2006,7 +1955,7 @@ call_find_module(char *name, PyObject *path)
 	else {
 		fob = Py_None;
 		Py_INCREF(fob);
-	}		
+	}
 	ret = Py_BuildValue("Os(ssi)",
 		      fob, pathname, fdp->suffix, fdp->mode, fdp->type);
 	Py_DECREF(fob);