[PATCH] debuginfod-support.c: Use long-lived debuginfod_client

[Aaron Merey <amerey@redhat.com>]

Apologies, resending this patch with a proper subject.

Aaron

From 54fa19c47f9beca1eaabd0f758333a9445084c0c Mon Sep 17 00:00:00 2001
From: Aaron Merey <amerey@redhat.com>
Date: Fri, 30 Apr 2021 18:58:36 -0400
Subject: [PATCH] debuginfod-support.c: Use long-lived debuginfod_client

Instead of initializing a new debuginfod_client for each query, store
the first initialized client for the remainder of the GDB session and
use it for every debuginfod query.

In conjunction with upcoming changes to libdebuginfod, using one client
for all queries will avoid latency caused by unneccesarily setting up
TCP connections multiple times.

Tested on Fedora 33 x86_64.

gdb/ChangeLog:

	* debuginfod-support.c (debuginfod_init): Use one client for
	all queries.
	(struct debuginfod_client_deleter): Remove.
---
 gdb/debuginfod-support.c | 41 ++++++++++++++++++----------------------
 1 file changed, 18 insertions(+), 23 deletions(-)

diff --git a/gdb/debuginfod-support.c b/gdb/debuginfod-support.c
index 9778e2e4cfe..357cd3f6d01 100644
--- a/gdb/debuginfod-support.c
+++ b/gdb/debuginfod-support.c
@@ -55,23 +55,13 @@ struct user_data
   gdb::optional<ui_out::progress_meter> meter;
 };
 
-/* Deleter for a debuginfod_client.  */
-
-struct debuginfod_client_deleter
-{
-  void operator() (debuginfod_client *c)
-  {
-    debuginfod_end (c);
-  }
-};
-
-using debuginfod_client_up
-  = std::unique_ptr<debuginfod_client, debuginfod_client_deleter>;
+static debuginfod_client *global_client = nullptr;
 
 static int
 progressfn (debuginfod_client *c, long cur, long total)
 {
   user_data *data = static_cast<user_data *> (debuginfod_get_user_data (c));
+  gdb_assert (data != nullptr);
 
   if (check_quit_flag ())
     {
@@ -103,15 +93,18 @@ progressfn (debuginfod_client *c, long cur, long total)
   return 0;
 }
 
-static debuginfod_client_up
+static debuginfod_client *
 debuginfod_init ()
 {
-  debuginfod_client_up c (debuginfod_begin ());
+  if (global_client == nullptr)
+    {
+      global_client = debuginfod_begin ();
 
-  if (c != nullptr)
-    debuginfod_set_progressfn (c.get (), progressfn);
+      if (global_client != nullptr)
+	debuginfod_set_progressfn (global_client, progressfn);
+    }
 
-  return c;
+  return global_client;
 }
 
 /* See debuginfod-support.h  */
@@ -126,19 +119,20 @@ debuginfod_source_query (const unsigned char *build_id,
   if (urls_env_var == NULL || urls_env_var[0] == '\0')
     return scoped_fd (-ENOSYS);
 
-  debuginfod_client_up c = debuginfod_init ();
+  debuginfod_client *c = debuginfod_init ();
 
   if (c == nullptr)
     return scoped_fd (-ENOMEM);
 
   user_data data ("source file", srcpath);
 
-  debuginfod_set_user_data (c.get (), &data);
-  scoped_fd fd (debuginfod_find_source (c.get (),
+  debuginfod_set_user_data (c, &data);
+  scoped_fd fd (debuginfod_find_source (c,
 					build_id,
 					build_id_len,
 					srcpath,
 					nullptr));
+  debuginfod_set_user_data (c, nullptr);
 
   /* TODO: Add 'set debug debuginfod' command to control when error messages are shown.  */
   if (fd.get () < 0 && fd.get () != -ENOENT)
@@ -164,7 +158,7 @@ debuginfod_debuginfo_query (const unsigned char *build_id,
   if (urls_env_var == NULL || urls_env_var[0] == '\0')
     return scoped_fd (-ENOSYS);
 
-  debuginfod_client_up c = debuginfod_init ();
+  debuginfod_client *c = debuginfod_init ();
 
   if (c == nullptr)
     return scoped_fd (-ENOMEM);
@@ -172,9 +166,10 @@ debuginfod_debuginfo_query (const unsigned char *build_id,
   char *dname = nullptr;
   user_data data ("separate debug info for", filename);
 
-  debuginfod_set_user_data (c.get (), &data);
-  scoped_fd fd (debuginfod_find_debuginfo (c.get (), build_id, build_id_len,
+  debuginfod_set_user_data (c, &data);
+  scoped_fd fd (debuginfod_find_debuginfo (c, build_id, build_id_len,
 					   &dname));
+  debuginfod_set_user_data (c, nullptr);
 
   if (fd.get () < 0 && fd.get () != -ENOENT)
     printf_filtered (_("Download failed: %s.  Continuing without debug info for %ps.\n"),
-- 
2.30.2