2 files changed, 23 insertions, 0 deletions

diff --git a/firmware/include/buflib.h b/firmware/include/buflib.h
index 45446c3b86..d2231ab79d 100644
--- a/firmware/include/buflib.h
+++ b/firmware/include/buflib.h
@@ -38,6 +38,7 @@ union buflib_data
     intptr_t val;                 /* length of the block in n*sizeof(union buflib_data).
                                      Includes buflib metadata overhead. A negative value
                                      indicates block is unallocated */
+    volatile unsigned pincount;   /* number of pins */
     struct buflib_callbacks* ops; /* callback functions for move and shrink. Can be NULL */
     char* alloc;                  /* start of allocated memory area */
     union buflib_data *handle;    /* pointer to entry in the handle table.
@@ -292,6 +293,25 @@ static inline void* buflib_get_data(struct buflib_context *ctx, int handle)
 bool buflib_shrink(struct buflib_context *ctx, int handle, void* newstart, size_t new_size);
 
 /**
+ * Increment the pin count for a handle. When pinned the handle will not
+ * be moved and move callbacks will not be triggered, allowing a pointer
+ * to the buffer to be kept across yields or used for I/O.
+ *
+ * Note that shrink callbacks can still be invoked for pinned handles.
+ */
+void buflib_pin(struct buflib_context *ctx, int handle);
+
+/**
+ * Decrement the pin count for a handle.
+ */
+void buflib_unpin(struct buflib_context *ctx, int handle);
+
+/**
+ * Get the current pin count of a handle. Zero means the handle is not pinned.
+ */
+unsigned buflib_pin_count(struct buflib_context *ctx, int handle);
+
+/**
  * Frees memory associated with the given handle
  *
  * Returns: 0 (to invalidate handles in one line, 0 is not a valid handle)
diff --git a/firmware/include/core_alloc.h b/firmware/include/core_alloc.h
index f535fc1f6e..87246bcbd6 100644
--- a/firmware/include/core_alloc.h
+++ b/firmware/include/core_alloc.h
@@ -14,6 +14,9 @@ int core_alloc(const char* name, size_t size);
 int core_alloc_ex(const char* name, size_t size, struct buflib_callbacks *ops);
 int core_alloc_maximum(const char* name, size_t *size, struct buflib_callbacks *ops);
 bool core_shrink(int handle, void* new_start, size_t new_size);
+void core_pin(int handle);
+void core_unpin(int handle);
+unsigned core_pin_count(int handle);
 int core_free(int handle);
 size_t core_available(void);
 size_t core_allocatable(void);