From e35fb433456859d250d2e075350d11d4e173713b Mon Sep 17 00:00:00 2001
From: Ralph Corderoy <ralph@inputplus.co.uk>
Date: Sun, 10 Sep 2017 14:22:29 +0100
Subject: [PATCH] get_file_info(): Flip logic throughout, reducing nesting.

Now a series of small paragraphs, each of which might return on error.
Also, the Cygwin oddity described in the comment needs no special
handling given the recent bug fixes so it can be deleted.
---
 sbr/mime_type.c | 85 +++++++++++++++++++++++--------------------------
 1 file changed, 39 insertions(+), 46 deletions(-)

diff --git a/sbr/mime_type.c b/sbr/mime_type.c
index 47c68334..a640110a 100644
--- a/sbr/mime_type.c
+++ b/sbr/mime_type.c
@@ -114,63 +114,56 @@ mime_type(const char *file_name) {
  * Get information using proc about a file.
  */
 static char *
-get_file_info(const char *proc, const char *file_name) {
-    char *cmd, *cp;
-    char *quotec = "'";
+get_file_info(const char *proc, const char *file_name)
+{
+    char *quotec;
+    char *cmd;
+    FILE *fp;
+    bool ok;
     char buf[max(BUFSIZ, 2048)];
+    char *info;
+    char *needle;
 
-    if ((cp = strchr(file_name, '\''))) {
-        /* file_name contains a single quote. */
+    if (strchr(file_name, '\'')) {
         if (strchr(file_name, '"')) {
             inform("filenames containing both single and double quotes "
-                   "are unsupported for attachment");
+                "are unsupported for attachment");
             return NULL;
         }
         quotec = "\"";
-    }
-
-    cp = NULL;
-    if ((cmd = concat(proc, " ", quotec, file_name, quotec, NULL))) {
-        FILE *fp;
-
-        if ((fp = popen(cmd, "r")) != NULL) {
-
-            buf[0] = '\0';
-            if (fgets(buf, sizeof buf, fp)) {
-                char *eol;
-
-                /* Skip leading <filename>:<whitespace>, if present. */
-                if ((cp = strchr(buf, ':')) != NULL) {
-                    ++cp;
-                    while (*cp  &&  isblank((unsigned char) *cp)) {
-                        ++cp;
-                    }
-                } else {
-                    cp = buf;
-                }
-
-                /* Truncate at newline (LF or CR), if present. */
-                if ((eol = strpbrk(cp, "\n\r")) != NULL) {
-                    *eol = '\0';
-                }
-            } else if (buf[0] == '\0') {
-                /* This can happen on Cygwin if the popen()
-                   mysteriously fails.  Return NULL so that the caller
-                   will use another method to determine the info. */
-                free (cp);
-                cp = NULL;
-            }
+    } else
+        quotec = "'";
 
-            (void) pclose(fp);
-        } else {
-            inform("no output from %s", cmd);
-        }
+    cmd = concat(proc, " ", quotec, file_name, quotec, NULL);
+    if (!cmd) {
+        inform("concat with \"%s\" failed, out of memory?", proc);
+        return NULL;
+    }
 
+    if ((fp = popen(cmd, "r")) == NULL) {
+        inform("no output from %s", cmd);
         free(cmd);
-    } else {
-        inform("concat with \"%s\" failed, out of memory?", proc);
+        return NULL;
     }
 
-    return cp  ?  strdup(cp)  :  NULL;
+    ok = fgets(buf, sizeof buf, fp);
+    free(cmd);
+    (void)pclose(fp);
+    if (!ok)
+        return NULL;
+
+    /* s#^.*:[ \t]*##. */
+    info = buf;
+    if ((needle = strchr(info, ':'))) {
+        info = needle + 1;
+        while (isblank((unsigned char)*info))
+            info++;
+    }
+
+    /* s#[\n\r].*##. */
+    if ((needle = strpbrk(info, "\n\r")))
+        *needle = '\0';
+
+    return strdup(info);
 }
 #endif /* MIMETYPEPROC */
-- 
2.56.0