Add get user agent functionality.

CHANGELOG.md

@@ -12,6 +12,10 @@ v0.24 + 1
 
 ### API additions
 
+* You can now get the user-agent used by libgit2 using the
+  `GIT_OPT_GET_USER_AGENT` option with `git_libgit2_opts()`.
+  It is the counterpart to `GIT_OPT_SET_USER_AGENT`.
+
 * `git_commit_create_buffer()` creates a commit and writes it into a
   user-provided buffer instead of writing it into the object db.
 

include/git2/common.h

@@ -158,6 +158,7 @@ typedef enum {
 	GIT_OPT_SET_USER_AGENT,
 	GIT_OPT_ENABLE_STRICT_OBJECT_CREATION,
 	GIT_OPT_SET_SSL_CIPHERS,
+	GIT_OPT_GET_USER_AGENT,
 } git_libgit2_opt_t;
 
 /**

src/settings.c

@@ -209,6 +209,14 @@ int git_libgit2_opts(int key, ...)
 #endif
 		break;
 
+	case GIT_OPT_GET_USER_AGENT:
+		{
+			git_buf *out = va_arg(ap, git_buf *);
+			git_buf_sanitize(out);
+			error = git_buf_sets(out, git__user_agent);
+		}
+		break;
+
 	default:
 		giterr_set(GITERR_INVALID, "invalid option key");
 		error = -1;

tests/core/useragent.c

@@ -4,8 +4,14 @@
 void test_core_useragent__get(void)
 {
 	const char *custom_name = "super duper git";
+	git_buf buf = GIT_BUF_INIT;
 
 	cl_assert_equal_p(NULL, git_libgit2__user_agent());
 	cl_git_pass(git_libgit2_opts(GIT_OPT_SET_USER_AGENT, custom_name));
 	cl_assert_equal_s(custom_name, git_libgit2__user_agent());
+
+	cl_git_pass(git_libgit2_opts(GIT_OPT_GET_USER_AGENT, &buf));
+	cl_assert_equal_s(custom_name, buf.ptr);
+
+	git_buf_free(&buf);
 }