Add block parameter to lilv_flock

3 files changed, 12 insertions, 7 deletions

diff --git a/src/filesystem.c b/src/filesystem.c
index a12dcba..6b17ccb 100644
--- a/src/filesystem.c
+++ b/src/filesystem.c
@@ -270,10 +270,11 @@ lilv_symlink(const char* oldpath, const char* newpath)
 }
 
 int
-lilv_flock(FILE* file, bool lock)
+lilv_flock(FILE* file, bool lock, bool block)
 {
 #if defined(HAVE_FLOCK) && defined(HAVE_FILENO)
-	return flock(fileno(file), lock ? LOCK_EX : LOCK_UN);
+	return flock(fileno(file),
+	             (lock ? LOCK_EX : LOCK_UN) | (block ? 0 : LOCK_NB));
 #else
 	return 0;
 #endif
diff --git a/src/filesystem.h b/src/filesystem.h
index 1b29d42..9cf6e4b 100644
--- a/src/filesystem.h
+++ b/src/filesystem.h
@@ -88,13 +88,17 @@ lilv_symlink(const char* oldpath, const char* newpath);
 /**
    Set or remove an advisory exclusive lock on `file`.
 
-   If the `lock` is true and the file is already locked, then this will not
-   succeed and non-zero will be returned.
+   If the `lock` is true and the file is already locked by another process, or
+   by this process via a different file handle, then this will not succeed and
+   non-zero will be returned.
 
+   @param file Handle for open file to lock.
+   @param lock True to set lock, false to release lock.
+   @param block If true, then this call will block until the lock is acquired.
    @return Zero on success.
 */
 int
-lilv_flock(FILE* file, bool lock);
+lilv_flock(FILE* file, bool lock, bool block);
 
 /**
    Visit every file in the directory at `path`.
diff --git a/src/state.c b/src/state.c
index 2b7cde9..3086ea6 100644
--- a/src/state.c
+++ b/src/state.c
@@ -902,7 +902,7 @@ add_state_to_manifest(LilvWorld*      lworld,
 	if (rfd) {
 		// Read manifest into model
 		SerdReader* reader = sord_new_reader(model, env, SERD_TURTLE, NULL);
-		lilv_flock(rfd, true);
+		lilv_flock(rfd, true, true);
 		serd_reader_read_file_handle(reader, rfd, manifest.buf);
 		serd_reader_free(reader);
 	}
@@ -952,7 +952,7 @@ add_state_to_manifest(LilvWorld*      lworld,
 	serd_env_free(env);
 
 	if (rfd) {
-		lilv_flock(rfd, false);
+		lilv_flock(rfd, false, true);
 		fclose(rfd);
 	}