uip/scansbr.c: Stop `scan -file' copying mailbox to /dev/null.

scan() was copying the mailbox to /dev/null when called for `scan -file
foo.mbox' because it used outnum being non-zero as the test of whether
to write instead of FILE pointer scnout being non-NULL.  By switching,
we can avoid the opening of /dev/null that was just to give scnout a
valid value for the needless fputs(3), etc.

Add comment explaining scan()'s outnum input parameter's three
functions: -1, 0, and positive.

diff --git a/uip/scansbr.c b/uip/scansbr.c
index 569991e..a62faf2 100644 (file)
--- a/uip/scansbr.c
+++ b/uip/scansbr.c
@@ -31,6 +31,15 @@ static m_getfld_state_t gstate;              /* for accessor functions below    */
                    DIEWRERR();\
                }
 
+/* outnum determines how the input from inb is copied.  If positive then
+ * it is the number of the message to create, e.g. for inc(1), and all
+ * of the email is copied into that message, with some tweaks.  If 0,
+ * e.g. `scan 42', then reading inb can dubiously stop after a whole
+ * buffer of body, even though this might not be enough to fulfill the
+ * scan format and width.  Or if -1 then no copy is being created, but
+ * all of inb must be read because the next message must be found, e.g.
+ * `scan -file foo.mbox'. */
+
 int
 scan (FILE *inb, int innum, int outnum, char *nfs, int width, int curflg,
       int unseen, char *folder, long size, int noisy, charstring_t *scanl)
@@ -143,16 +152,12 @@ scan (FILE *inb, int innum, int outnum, char *nfs, int width, int curflg,
         return SCNEOF;
     }
 
-    if (outnum) {
-       if (outnum > 0) {
-           scnmsg = m_name (outnum);
-           if (*scnmsg == '?')         /* msg num out of range */
-               return SCNNUM;
-       } else {
-           scnmsg = "/dev/null";
-       }
-       if ((scnout = fopen (scnmsg, "w")) == NULL)
-           adios (scnmsg, "unable to write");
+    if (outnum > 0) {
+        scnmsg = m_name (outnum);
+        if (*scnmsg == '?')            /* msg num out of range */
+            return SCNNUM;
+        if ((scnout = fopen (scnmsg, "w")) == NULL)
+            adios (scnmsg, "unable to write");
     }
 
     /* scan - main loop */
@@ -162,7 +167,7 @@ scan (FILE *inb, int innum, int outnum, char *nfs, int width, int curflg,
            case FLD: 
            case FLDPLUS: 
                compnum++;
-               if (outnum) {
+               if (scnout) {
                    FPUTS (name);
                    if ( putc (':', scnout) == EOF) DIEWRERR();
                    FPUTS (tmpbuf);
@@ -190,7 +195,7 @@ scan (FILE *inb, int innum, int outnum, char *nfs, int width, int curflg,
                while (state == FLDPLUS) {
                    bufsz = rlwidth;
                    state = m_getfld (&gstate, name, tmpbuf, &bufsz, inb);
-                   if (outnum)
+                   if (scnout)
                        FPUTS (tmpbuf);
                }
                break;
@@ -206,14 +211,16 @@ scan (FILE *inb, int innum, int outnum, char *nfs, int width, int curflg,
                    state = m_getfld (&gstate, name, tmpbuf + i, &bufsz, inb);
                }
 
-               if (! outnum) {
+               if (outnum == 0) {
                    state = FILEEOF; /* stop now if scan cmd */
                    if (bodycomp && startbody == NULL)
                        startbody = tmpbuf;
                    goto finished;
                }
-               if (putc ('\n', scnout) == EOF) DIEWRERR();
-               FPUTS (tmpbuf);
+                if (scnout) {
+                    if (putc ('\n', scnout) == EOF) DIEWRERR();
+                    FPUTS (tmpbuf);
+                }
                /*
                  * The previous code here used to call m_getfld() using
                  * pointers to the underlying output stdio buffers to
@@ -239,7 +246,8 @@ body:;
                while (state == BODY) {
                    bufsz = rlwidth;
                    state = m_getfld (&gstate, name, tmpbuf, &bufsz, inb);
-                   FPUTS(tmpbuf);
+                    if (scnout)
+                        FPUTS(tmpbuf);
                }
                goto finished;
 
@@ -253,7 +261,7 @@ body:;
 
                fprintf (stderr, "component %d\n", compnum);
 
-               if (outnum) {
+               if (scnout) {
                    FPUTS ("\n\nBAD MSG:\n");
                    FPUTS (name);
                    if (putc ('\n', scnout) == EOF) DIEWRERR();
@@ -287,7 +295,7 @@ finished:
 
     if (size)
        dat[2] = size;
-    else if (outnum > 0)
+    else if (scnout)
     {
        dat[2] = ftell(scnout);
        if (dat[2] == EOF) DIEWRERR();
@@ -327,7 +335,7 @@ finished:
        cptr->c_text = NULL;
     }
 
-    if (outnum && (ferror(scnout) || fclose (scnout) == EOF))
+    if (scnout && (ferror(scnout) || fclose (scnout) == EOF))
        DIEWRERR();
 
     return (state != FILEEOF ? SCNERR : encrypted ? SCNENC : SCNMSG);