compat: rename {,notmuch_}canonicalize_file_name

When compat canonicalize_file_name was introduced, it was limited to
C code only because it was used by C code only during that time.

>From 5ec6fd4d, (lib/open: check for split configuration when creating
database., 2021-02-16), lib/open.cc, which is C++, relies on the
existent of canonicalize_file_name.

However, we can't blindly enable canonicalize_file_name for C++ code,
because different implementation has different additional signature for
C++ and users can arbitrarily add -DHAVE_CANONICALIZE_FILE_NAME=0 to
{C,CXX}FLAGS.

Let's move our implementation into a util library.

Helped-by: Tomi Ollila <tomi.ollila@iki.fi>
Signed-off-by: Đoàn Trần Công Danh <congdanhqx@gmail.com>

compat/Makefile.local

@@ -5,10 +5,6 @@ extra_cflags += -I$(srcdir)/$(dir)
 
 notmuch_compat_srcs :=
 
-ifneq ($(HAVE_CANONICALIZE_FILE_NAME),1)
-notmuch_compat_srcs += $(dir)/canonicalize_file_name.c
-endif
-
 ifneq ($(HAVE_GETLINE),1)
 notmuch_compat_srcs += $(dir)/getline.c $(dir)/getdelim.c
 endif

compat/compat.h

@@ -37,14 +37,6 @@ extern "C" {
 #define _POSIX_PTHREAD_SEMANTICS 1
 #endif
 
-#if ! HAVE_CANONICALIZE_FILE_NAME
-/* we only call this function from C, and this makes testing easier */
-#ifndef __cplusplus
-char *
-canonicalize_file_name (const char *path);
-#endif
-#endif
-
 #if ! HAVE_GETLINE
 #include <stdio.h>
 #include <unistd.h>

lib/open.cc

@@ -3,6 +3,7 @@
 
 #include "database-private.h"
 #include "parse-time-vrp.h"
+#include "path-util.h"
 
 #if HAVE_XAPIAN_DB_RETRY_LOCK
 #define DB_ACTION (Xapian::DB_CREATE_OR_OPEN | Xapian::DB_RETRY_LOCK)
@@ -612,9 +613,9 @@ notmuch_database_create_with_config (const char *database_path,
     _set_database_path (notmuch, database_path);
 
     if (key_file && ! split) {
-	char *mail_root = canonicalize_file_name (
+	char *mail_root = notmuch_canonicalize_file_name (
 	    g_key_file_get_value (key_file, "database", "mail_root", NULL));
-	char *db_path = canonicalize_file_name (database_path);
+	char *db_path = notmuch_canonicalize_file_name (database_path);
 
 	split = (mail_root && (0 != strcmp (mail_root, db_path)));
 

notmuch-config.c

@@ -24,6 +24,7 @@
 #include <netdb.h>
 #include <assert.h>
 
+#include "path-util.h"
 #include "unicode-util.h"
 
 static const char toplevel_config_comment[] =
@@ -327,7 +328,7 @@ notmuch_conffile_save (notmuch_conffile_t *config)
     }
 
     /* Try not to overwrite symlinks. */
-    filename = canonicalize_file_name (config->filename);
+    filename = notmuch_canonicalize_file_name (config->filename);
     if (! filename) {
 	if (errno == ENOENT) {
 	    filename = strdup (config->filename);

util/Makefile.local

@@ -6,7 +6,7 @@ extra_cflags += -I$(srcdir)/$(dir)
 libnotmuch_util_c_srcs := $(dir)/xutil.c $(dir)/error_util.c $(dir)/hex-escape.c \
 		  $(dir)/string-util.c $(dir)/talloc-extra.c $(dir)/zlib-extra.c \
 		$(dir)/util.c $(dir)/gmime-extra.c $(dir)/crypto.c \
-		$(dir)/repair.c \
+		$(dir)/repair.c $(dir)/path-util.c \
 		$(dir)/unicode-util.c
 
 libnotmuch_util_modules := $(libnotmuch_util_c_srcs:.c=.o)

util/path-util.c

@@ -1,12 +1,21 @@
-#include "compat.h"
+/*
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+#define _GNU_SOURCE
+
+#include "path-util.h"
+
 #include <limits.h>
-#undef _GNU_SOURCE
 #include <stdlib.h>
 
+
 char *
-canonicalize_file_name (const char *path)
+notmuch_canonicalize_file_name (const char *path)
 {
-#ifdef PATH_MAX
+#if HAVE_CANONICALIZE_FILE_NAME
+    return canonicalize_file_name (path);
+#elif defined(PATH_MAX)
     char *resolved_path =  malloc (PATH_MAX + 1);
     if (resolved_path == NULL)
 	return NULL;

util/path-util.h

@@ -0,0 +1,19 @@
+/*
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+#ifndef NOTMUCH_UTIL_PATH_UTIL_H_
+#define NOTMUCH_UTIL_PATH_UTIL_H_
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+char *
+notmuch_canonicalize_file_name (const char *path);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* NOTMUCH_UTIL_PATH_UTIL_H_ */