moved the handling of SFTP handles to new linked list code

Each SFTP file handle is now handled by the "mother-struct"
using the generic linked list functions. The goal is to move
all custom linked list code to use this set of functions.

I also moved the list declarations to the misc.h where they
belong and made misc.h no longer include libssh2_priv.h itself
since now libssh2_priv.h needs misc.h...

In misc.c I added a #if 0'ed _libssh2_list_insert() function
because I ended up writing one, and I believe we may need it here
too once we move over more stuff to use the _libssh2_list* family.

src/libssh2_priv.h

@@ -85,6 +85,7 @@
 #include "libssh2.h"
 #include "libssh2_publickey.h"
 #include "libssh2_sftp.h"
+#include "misc.h" /* for the linked list stuff */
 
 #ifndef FALSE
 #define FALSE 0
@@ -547,8 +548,9 @@ struct _LIBSSH2_PUBLICKEY
 
 struct _LIBSSH2_SFTP_HANDLE
 {
+    struct list_node node;
+
     LIBSSH2_SFTP *sftp;
-    LIBSSH2_SFTP_HANDLE *prev, *next;
 
     /* This is a pre-allocated buffer used for sending SFTP requests as the
        whole thing might not get sent in one go. This buffer is used for read,
@@ -588,7 +590,8 @@ struct _LIBSSH2_SFTP
 
     LIBSSH2_PACKET_BRIGADE packets;
 
-    LIBSSH2_SFTP_HANDLE *handles;
+    /* a list of _LIBSSH2_SFTP_HANDLE structs */
+    struct list_head sftp_handles;
 
     unsigned long last_errno;
 
@@ -928,22 +931,6 @@ struct _LIBSSH2_SESSION
 #define LIBSSH2_SOCKET_RECV_FLAGS(session)      0
 #endif
 
-/* -------- */
-
-/* First take towards a generic linked list handling code for libssh2
-   internals */
-
-struct list_head {
-    struct list_node *last;
-    struct list_node *first;
-};
-
-struct list_node {
-    struct list_node *next;
-    struct list_node *prev;
-    struct list_head *head;
-};
-
 /* --------- */
 
 /* libssh2 extensible ssh api, ultimately I'd like to allow loading additional

src/misc.c

@@ -426,3 +426,30 @@ void _libssh2_list_remove(struct list_node *entry)
     else
         entry->head->last = entry->prev;
 }
+
+#if 0
+/* insert a node before the given 'after' entry */
+void _libssh2_list_insert(struct list_node *after, /* insert before this */
+                          struct list_node *entry)
+{
+    /* 'after' is next to 'entry' */
+    bentry->next = after;
+
+    /* entry's prev is then made to be the prev after current has */
+    entry->prev = after->prev;
+
+    /* the node that is now before 'entry' was previously before 'after'
+       and must be made to point to 'entry' correctly */
+    if(entry->prev)
+        entry->prev->next = entry;
+
+    /* after's prev entry points back to entry */
+    after->prev = entry;
+
+    /* after's next entry is still the same as before */
+
+    /* entry's head is the same as after's */
+    entry->head = after->head;
+}
+
+#endif

src/misc.h

@@ -38,7 +38,16 @@
  * OF SUCH DAMAGE.
  */
 
-#include "libssh2_priv.h"
+struct list_head {
+    struct list_node *last;
+    struct list_node *first;
+};
+
+struct list_node {
+    struct list_node *next;
+    struct list_node *prev;
+    struct list_head *head;
+};
 
 void _libssh2_list_init(struct list_head *head);
 
@@ -58,6 +67,6 @@ void *_libssh2_list_prev(struct list_node *node);
 /* remove this node from the list */
 void _libssh2_list_remove(struct list_node *entry);
 
-size_t _libssh2_base64_encode(LIBSSH2_SESSION *session,
+size_t _libssh2_base64_encode(struct _LIBSSH2_SESSION *session,
                               const char *inp, size_t insize, char **outptr);
 #endif /* _LIBSSH2_MISC_H */

src/sftp.c

@@ -556,8 +556,8 @@ static LIBSSH2_SFTP *sftp_init(LIBSSH2_SESSION *session)
          * as the SFTP session is created they are cleared and can thus be
          * re-used again to allow any amount of SFTP handles per sessions.
          *
-         * Note that you MUST NOT try to call libssh2_sftp_init() to get
-         * another handle until the previous one has finished and either
+         * Note that you MUST NOT try to call libssh2_sftp_init() again to get
+         * another handle until the previous call has finished and either
          * succesffully made a handle or failed and returned error (not
          * including *EAGAIN).
          */
@@ -715,6 +715,8 @@ static LIBSSH2_SFTP *sftp_init(LIBSSH2_SESSION *session)
     session->sftpInit_sftp = NULL;
     session->sftpInit_channel = NULL;
 
+    _libssh2_list_init(&sftp_handle->sftp_handles);
+
     return sftp_handle;
 
   sftp_init_error:
@@ -798,6 +800,9 @@ sftp_shutdown(LIBSSH2_SFTP *sftp)
         sftp->symlink_packet = NULL;
     }
 
+    /* TODO: We should consider walking over the sftp_handles list and kill
+     * any remaining sftp handles ... */
+
     rc = _libssh2_channel_free(sftp->channel);
 
     return rc;
@@ -985,12 +990,10 @@ sftp_open(LIBSSH2_SFTP *sftp, const char *filename,
     memcpy(fp->handle, data + 9, fp->handle_len);
     LIBSSH2_FREE(session, data);
 
-    /* Link the file and the sftp session together */
-    fp->next = sftp->handles;
-    if (fp->next) {
-        fp->next->prev = fp;
-    }
-    fp->sftp = sftp;
+    /* add this file handle to the list kept in the sftp session */
+    _libssh2_list_add(&sftp->sftp_handles, &fp->node);
+
+    fp->sftp = sftp; /* point to the parent struct */
 
     fp->u.file.offset = 0;
 
@@ -1775,12 +1778,8 @@ sftp_close_handle(LIBSSH2_SFTP_HANDLE *handle)
         return -1;
     }
 
-    if (handle == sftp->handles) {
-        sftp->handles = handle->next;
-    }
-    if (handle->next) {
-        handle->next->prev = NULL;
-    }
+    /* remove this handle from the parent's list */
+    _libssh2_list_remove(&handle->node);
 
     if ((handle->handle_type == LIBSSH2_SFTP_HANDLE_DIR)
         && handle->u.dir.names_left) {