Copy the dependencies from sawmill project

1 files changed, 71 insertions, 0 deletions

diff --git a/src/safe_fifo.h b/src/safe_fifo.h
new file mode 100644
index 0000000..4644c33
--- /dev/null
+++ b/src/safe_fifo.h
@@ -0,0 +1,71 @@
+/**
+ * \file safe_fifo.h
+ * Thread-safe FIFO queue.
+ */
+
+#ifndef SAFE_FIFO_H
+#define SAFE_FIFO_H
+
+#include "timespec.h"
+
+/**
+ * Opaque type describing a thread-safe FIFO queue
+ */
+typedef struct safe_fifo_t safe_fifo_t;
+
+/**
+ * Create a new queue.
+ * The new queue will have a reference count of one.
+ * Returns NULL in case of allocation errors.
+ * @return a new queue
+ */
+MALLOC safe_fifo_t* safe_fifo_new(void);
+
+/**
+ * Increase the reference count on the queue.
+ * @param fifo queue, may not be NULL
+ */
+NONULL void safe_fifo_ref(safe_fifo_t* fifo);
+
+/**
+ * Decrease the reference count on the queue and free if it goes down to zero.
+ * @param fifo queue, may be NULL
+ */
+void safe_fifo_unref(safe_fifo_t* fifo);
+
+/**
+ * Push an item on the queue.
+ * Will never block. In case of allocation errors, new items are ignored.
+ * @param fifo queue, may not be NULL
+ * @param item pointer to add to queue, may not be NULL
+ */
+NONULL void safe_fifo_push(safe_fifo_t* fifo, void* item);
+
+/**
+ * Pop an item from the queue.
+ * Will block until there is an item available.
+ * @param fifo queue, may not be NULL
+ * @return oldest item pushed onto the queue
+ */
+NONULL void* safe_fifo_pop(safe_fifo_t* fifo);
+
+/**
+ * Try to pop an item from the queue.
+ * Will not wait until there is an item available.
+ * @param fifo queue, may not be NULL
+ * @return oldest item in queue if any otherwise NULL
+ */
+NONULL void* safe_fifo_trypop(safe_fifo_t* fifo);
+
+/**
+ * Try to pop an item from the queue.
+ * Waits until abstime has occurred before giving up and returning NULL.
+ * Use thread_abstime() to fill out the abstime.
+ * @param fifo queue, may not be NULL
+ * @param abstime absolute time when to give up
+ * @return oldest item in queue if any otherwise NULL
+ */
+NONULL void* safe_fifo_timedpop(safe_fifo_t* fifo,
+                                const struct timespec *abstime);
+
+#endif /* SAFE_FIFO_H */