obv patch: $DEBUGINFOD_PROGRESS formatting

[Frank Ch. Eigler]

Hi -

pushing as obvious:


Author: Frank Ch. Eigler <fche@redhat.com>
Date:   Sun Mar 29 15:10:37 2020 -0400

    debuginfod-client default_progressfn: formatting fix
    
    The saga of clean $DEBUGINFOD_PROGRESS=1 output continues.  Previous
    code would sometimes insert a \n (a blank line) into the output
    stream, even if the target file was found in a cache and thus the
    progressfn was never called.  New code sets a client flag to track
    this case more precisely.
    
    Signed-off-by: Frank Ch. Eigler <fche@redhat.com>

diff --git a/debuginfod/ChangeLog b/debuginfod/ChangeLog
index 193c27210855..9901c521de53 100644
--- a/debuginfod/ChangeLog
+++ b/debuginfod/ChangeLog
@@ -1,3 +1,11 @@
+2020-03-29  Frank Ch. Eigler  <fche@redhat.com>
+
+	* debuginfod-client.c (struct debuginfod_client): Add a flag field
+	for progressfn printing.
+	(default_progressfn): Set it if printing \rsomething.
+	(debuginfod_end): Terminate with \n if flag set, i.e., only if the
+	default_progressfn was actually called.
+
 2020-03-27  Mark Wielaard  <mark@klomp.org>
 
 	* debuginfod.cxx (parse_opt): Check port is not zero.
diff --git a/debuginfod/debuginfod-client.c b/debuginfod/debuginfod-client.c
index 043e8aa24fac..fa017a84c7cf 100644
--- a/debuginfod/debuginfod-client.c
+++ b/debuginfod/debuginfod-client.c
@@ -89,6 +89,10 @@ struct debuginfod_client
   int user_agent_set_p; /* affects add_default_headers */
   struct curl_slist *headers;
 
+  /* Flags the default_progressfn having printed something that
+     debuginfod_end needs to terminate. */
+  int default_progressfn_printed_p;
+
   /* Can contain all other context, like cache_path, server_urls,
      timeout or other info gotten from environment variables, the
      handle data, etc. So those don't have to be reparsed and
@@ -438,6 +442,7 @@ default_progressfn (debuginfod_client *c, long a, long b)
     dprintf(STDERR_FILENO,
             "\rDownloading from %.*s %ld/%ld",
             len, url, a, b);
+  c->default_progressfn_printed_p = 1;
 
   return 0;
 }
@@ -935,7 +940,10 @@ debuginfod_query_server (debuginfod_client *c,
 /* general purpose exit */
  out:
   /* Conclude the last \r status line */
-  if (c->progressfn == & default_progressfn)
+  /* Another possibility is to use the ANSI CSI n K EL "Erase in Line"
+     code.  That way, the previously printed messages would be erased,
+     and without a newline. */
+  if (c->default_progressfn_printed_p)
     dprintf(STDERR_FILENO, "\n");
 
   free (cache_path);