From: Nicolas Pennequin <nicolas.pennequin@free.fr>
Date: Tue, 7 Aug 2007 20:07:23 +0000 (+0200)
Subject: bufopen: Factor out the pre-checking.
X-Git-Tag: working_mob_2~2
X-Git-Url: https://repo.or.cz/w/Rockbox-MoB.git/commitdiff_plain/dc66c7e0f5aab33aff79538afbb0f20484e4b7c4

bufopen: Factor out the pre-checking.

Factored out the code that checks there is enough space to finish buffering
the current handle. It will be used again in the next commit.
---

diff --git a/testplugin.c b/testplugin.c
index 3cc2db0..cf9e44f 100644
--- a/testplugin.c
+++ b/testplugin.c
@@ -299,6 +299,7 @@ BUFFER SPACE MANAGEMENT
 buffer_handle   : Buffer data for a handle
 free_buffer     : Free buffer space by moving a handle
 fill_buffer     : Call buffer_handle for all handles that have data to buffer
+can_add_handle  : Indicate whether it's safe to add a handle.
 data_rem        : Total amount of data needing to be buffered
 wasted_space    : Total amount of space available for freeing
 
@@ -433,6 +434,29 @@ static void fill_buffer(void)
     }
 }
 
+/* Check whether it's safe to add a new handle and reserve space to let the
+   current one finish buffering its data. Used by bufopen and bufgetdata as
+   a preliminary check before even trying to physically add the handle.
+   Returns true if it's ok to add a new handle, false if not.
+*/
+static bool can_add_handle(void)
+{
+    if (cur_handle && cur_handle->filerem > 0) {
+        /* the current handle hasn't finished buffering. We can only add
+           a new one if there is already enough free space to finish
+           the buffering. */
+        if (cur_handle->filerem < (buffer_len - BUF_USED)) {
+            /* Before adding the new handle we reserve some space for the
+               current one to finish buffering its data. */
+            buf_widx = RINGBUF_ADD(buf_widx, cur_handle->filerem);
+        } else {
+            return false;
+        }
+    }
+
+    return true;
+}
+
 /* Return the total amount of data left to be buffered for all the handles */
 static size_t data_rem(void)
 {
@@ -488,18 +512,8 @@ management functions for all the actual handle management work.
 */
 int bufopen(char *file, size_t offset, enum data_type type)
 {
-    if (cur_handle && cur_handle->filerem > 0) {
-        /* the current handle hasn't finished buffering. We can only add
-           a new one if there is already enough free space to finish
-           the buffering. */
-        if (cur_handle->filerem < (buffer_len - BUF_USED)) {
-            /* Before adding the new handle we reserve some space for the
-               current one to finish buffering its data. */
-            buf_widx = RINGBUF_ADD(buf_widx, cur_handle->filerem);
-        } else {
-            return -2;
-        }
-    }
+    if (!can_add_handle())
+        return -2;
 
     int fd = rb->open(file, O_RDONLY);
     if (fd < 0)