New event API (RHBZ#664558).

This API allows more than one callback to be registered for each
event, makes it possible to call the API from other languages, and
allows [nearly all] log, debug and trace messages to be rerouted from
stderr.

An older version of this API was discussed on the mailing list here:
https://www.redhat.com/archives/libguestfs/2010-December/msg00081.html
https://www.redhat.com/archives/libguestfs/2011-January/msg00012.html

This also updates guestfish to use the new API for its progress bars.

3 files changed, 135 insertions, 2 deletions

diff --git a/capitests/Makefile.am b/capitests/Makefile.am
index 83e62c8e..89d29e0b 100644
--- a/capitests/Makefile.am
+++ b/capitests/Makefile.am
@@ -31,7 +31,8 @@ check_PROGRAMS = \
 	test-config \
 	test-add-drive-opts \
 	test-last-errno \
-	test-private-data
+	test-private-data \
+	test-debug-to-file
 
 TESTS = \
 	tests \
@@ -40,7 +41,8 @@ TESTS = \
 	test-config \
 	test-add-drive-opts \
 	test-last-errno \
-	test-private-data
+	test-private-data \
+	test-debug-to-file
 
 # The API behind this test is not baked yet.
 #if HAVE_LIBVIRT
@@ -112,6 +114,13 @@ test_private_data_CFLAGS = \
 test_private_data_LDADD = \
 	$(top_builddir)/src/libguestfs.la
 
+test_debug_to_file_SOURCES = test-debug-to-file.c
+test_debug_to_file_CFLAGS = \
+	-I$(top_srcdir)/src -I$(top_builddir)/src \
+	$(WARN_CFLAGS) $(WERROR_CFLAGS)
+test_debug_to_file_LDADD = \
+	$(top_builddir)/src/libguestfs.la
+
 #if HAVE_LIBVIRT
 #test_add_libvirt_dom_SOURCES = test-add-libvirt-dom.c
 #test_add_libvirt_dom_CFLAGS = \
diff --git a/capitests/test-debug-to-file.c b/capitests/test-debug-to-file.c
new file mode 100644
index 00000000..6d1b619e
--- /dev/null
+++ b/capitests/test-debug-to-file.c
@@ -0,0 +1,89 @@
+/* libguestfs
+ * Copyright (C) 2011 Red Hat Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+/* Test that we can use the new event API to capture all debugging
+ * messages to a file.
+ */
+
+#include <config.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "guestfs.h"
+
+static void
+debug_to_file (guestfs_h *g,
+               void *opaque,
+               uint64_t event,
+               int event_handle,
+               int flags,
+               const char *buf, size_t buf_len,
+               const uint64_t *array, size_t array_len)
+{
+  FILE *fp = opaque;
+
+  fwrite (buf, 1, buf_len, fp);
+}
+
+int
+main (int argc, char *argv[])
+{
+  guestfs_h *g;
+  const char *filename = "test.log";
+  FILE *debugfp;
+
+  debugfp = fopen (filename, "w");
+  if (debugfp == NULL) {
+    perror (filename);
+    exit (EXIT_FAILURE);
+  }
+
+  g = guestfs_create ();
+  if (g == NULL) {
+    fprintf (stderr, "failed to create handle\n");
+    exit (EXIT_FAILURE);
+  }
+
+  if (guestfs_set_event_callback
+      (g, debug_to_file,
+       GUESTFS_EVENT_LIBRARY|GUESTFS_EVENT_APPLIANCE|GUESTFS_EVENT_TRACE,
+       0, debugfp) == -1)
+    exit (EXIT_FAILURE);
+
+  if (guestfs_set_verbose (g, 1) == -1)
+    exit (EXIT_FAILURE);
+
+  if (guestfs_set_trace (g, 1) == -1)
+    exit (EXIT_FAILURE);
+
+  if (guestfs_add_drive_opts (g, "/dev/null",
+                              GUESTFS_ADD_DRIVE_OPTS_FORMAT, "raw",
+                              GUESTFS_ADD_DRIVE_OPTS_READONLY, 1,
+                              -1) == -1)
+    exit (EXIT_FAILURE);
+
+  if (guestfs_launch (g) == -1)
+    exit (EXIT_FAILURE);
+
+  guestfs_close (g);
+
+  exit (EXIT_SUCCESS);
+}
diff --git a/capitests/test-private-data.c b/capitests/test-private-data.c
index fad88b58..f2ff647b 100644
--- a/capitests/test-private-data.c
+++ b/capitests/test-private-data.c
@@ -30,6 +30,34 @@
 
 #define PREFIX "test_"
 
+static size_t close_callback_called = 0;
+
+/* This callback deletes all test keys in the handle. */
+static void
+close_callback (guestfs_h *g,
+                void *opaque,
+                uint64_t event,
+                int event_handle,
+                int flags,
+                const char *buf, size_t buf_len,
+                const uint64_t *array, size_t array_len)
+{
+  const char *key;
+  void *data;
+
+  close_callback_called++;
+
+ again:
+  data = guestfs_first_private (g, &key);
+  while (data != NULL) {
+    if (strncmp (key, PREFIX, strlen (PREFIX)) == 0) {
+      guestfs_set_private (g, key, NULL);
+      goto again;
+    }
+    data = guestfs_next_private (g, &key);
+  }
+}
+
 int
 main (int argc, char *argv[])
 {
@@ -44,6 +72,10 @@ main (int argc, char *argv[])
     exit (EXIT_FAILURE);
   }
 
+  if (guestfs_set_event_callback (g, close_callback, GUESTFS_EVENT_CLOSE,
+                                  0, NULL) == -1)
+    exit (EXIT_FAILURE);
+
   guestfs_set_private (g, PREFIX "a", (void *) 1);
   guestfs_set_private (g, PREFIX "b", (void *) 2);
   guestfs_set_private (g, PREFIX "c", (void *) 3);
@@ -79,7 +111,10 @@ main (int argc, char *argv[])
   }
   assert (count == 1);
 
+  /* Closing should implicitly call the close_callback function. */
   guestfs_close (g);
 
+  assert (close_callback_called == 1);
+
   exit (EXIT_SUCCESS);
 }