[PATCH 1/2] test/count: replace use of gdb with a LD_PRELOAD shim

[David Bremner <david@tethera.net>]

There is a certain amount of boilerplate to pass the call on the
original function, so abstract it out as a C preprocessor macro, plus
some extra includes in notmuch-test.h
---
 test/T060-count.sh  | 29 +++++++++++++++++------------
 test/notmuch-test.h | 22 ++++++++++++++++++++++
 2 files changed, 39 insertions(+), 12 deletions(-)

diff --git a/test/T060-count.sh b/test/T060-count.sh
index 6ad80df9..acf51d88 100755
--- a/test/T060-count.sh
+++ b/test/T060-count.sh
@@ -102,22 +102,27 @@ output=$(sed 's/^\(A Xapian exception [^:]*\):.*$/\1/' OUTPUT)
 test_expect_equal "${output}" "A Xapian exception occurred opening database"
 restore_database
 
-cat <<EOF > count-files.gdb
-set breakpoint pending on
-set logging file count-files-gdb.log
-set logging on
-break count_files
-commands
-shell cp /dev/null ${MAIL_DIR}/.notmuch/xapian/postlist.*
-continue
-end
-run
+make_shim qsm-shim<<EOF
+#include <notmuch-test.h>
+notmuch_status_t
+notmuch_query_search_messages (notmuch_query_t *query, notmuch_messages_t **messages) {
+  static notmuch_status_t (*orig_notmuch_query_search_messages)
+	(notmuch_query_t *query, notmuch_messages_t **messages) = NULL;
+  TEST_SAVE_ORIG(notmuch_query_search_messages);
+
+  /* XXX WARNING THIS CORRUPTS THE DATABASE */
+  int fd = open("target_postlist",O_WRONLY|O_TRUNC);
+  if (fd < 0)
+    exit (8);
+
+  return orig_notmuch_query_search_messages(query, messages);
+}
 EOF
 
 backup_database
 test_begin_subtest "error message from query_search_messages"
-${TEST_GDB} --batch-silent --return-child-result -x count-files.gdb \
-    --args notmuch count --output=files '*' 2>OUTPUT 1>/dev/null
+ln -s ${MAIL_DIR}/.notmuch/xapian/postlist.* target_postlist
+notmuch_with_shim qsm-shim count --output=files '*' 2>OUTPUT 1>/dev/null
 cat <<EOF > EXPECTED
 notmuch count: A Xapian exception occurred
 A Xapian exception occurred performing query
diff --git a/test/notmuch-test.h b/test/notmuch-test.h
index 34dbb8e0..8613a299 100644
--- a/test/notmuch-test.h
+++ b/test/notmuch-test.h
@@ -3,6 +3,10 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <notmuch.h>
+#include <dlfcn.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
 
 inline static void
 expect0 (int line, notmuch_status_t ret)
@@ -14,4 +18,22 @@ expect0 (int line, notmuch_status_t ret)
 }
 
 #define EXPECT0(v)  expect0 (__LINE__, v);
+
+#define TEST_SAVE_ORIG(func) \
+  if (! orig_##func) { \
+    void *handle; \
+    char *error; \
+    handle = dlopen("libnotmuch.so", RTLD_LAZY); \
+    if (! handle) { \
+      fputs(dlerror(), stderr); \
+      exit(1); \
+    } \
+    orig_##func = dlsym(handle, #func); \
+    if ((error = dlerror()) != NULL) { \
+      fprintf(stderr, "%s\n", error); \
+      exit(1); \
+    } \
+  }
+
+
 #endif
-- 
2.33.0