volgen: reimplement volgen

Generating a volfile occurs in two steps:
- Build a graph (ie, glusterfs_graph_t instance) by graph manipulation
  primitives
- Write out the graph to a file by the the graph printing API.

Graph builder routines can optionally make use of a "modifier dict",
which can contain overrides wrt. volume options. This can be used
for a "dry-run" graph generation.

Signed-off-by: Csaba Henk <csaba@gluster.com>
Signed-off-by: Vijay Bellur <vijay@dev.gluster.com>

BUG: 1750 (clean up volgen)
URL: http://bugs.gluster.com/cgi-bin/bugzilla3/show_bug.cgi?id=1750

3 files changed, 51 insertions, 62 deletions

diff --git a/libglusterfs/src/graph-utils.h b/libglusterfs/src/graph-utils.h
index 359cdcc7a..c1c8c36d7 100644
--- a/libglusterfs/src/graph-utils.h
+++ b/libglusterfs/src/graph-utils.h
@@ -26,4 +26,6 @@ glusterfs_graph_print_file (FILE *file, glusterfs_graph_t *graph);
 char *
 glusterfs_graph_print_buf (glusterfs_graph_t *graph);
 
+int glusterfs_xlator_link (xlator_t *pxl, xlator_t *cxl);
+void glusterfs_graph_set_first (glusterfs_graph_t *graph, xlator_t *xl);
 #endif
diff --git a/libglusterfs/src/graph.c b/libglusterfs/src/graph.c
index 0c63c194d..c821b3c2a 100644
--- a/libglusterfs/src/graph.c
+++ b/libglusterfs/src/graph.c
@@ -124,12 +124,54 @@ _log_if_option_is_invalid (xlator_t *xl, data_pair_t *pair)
 
 
 int
+glusterfs_xlator_link (xlator_t *pxl, xlator_t *cxl)
+{
+        xlator_list_t   *xlchild = NULL;
+        xlator_list_t   *xlparent = NULL;
+        xlator_list_t  **tmp = NULL;
+
+        xlparent = (void *) GF_CALLOC (1, sizeof (*xlparent),
+                                       gf_common_mt_xlator_list_t);
+        if (!xlparent)
+                return -1;
+
+        xlchild = (void *) GF_CALLOC (1, sizeof (*xlchild),
+                                      gf_common_mt_xlator_list_t);
+        if (!xlchild) {
+                GF_FREE (xlparent);
+
+                return -1;
+        }
+
+        xlparent->xlator = pxl;
+        for (tmp = &cxl->parents; *tmp; tmp = &(*tmp)->next);
+        *tmp = xlparent;
+
+        xlchild->xlator = cxl;
+        for (tmp = &pxl->children; *tmp; tmp = &(*tmp)->next);
+        *tmp = xlchild;
+
+        return 0;
+}
+
+
+void
+glusterfs_graph_set_first (glusterfs_graph_t *graph, xlator_t *xl)
+{
+        xl->next = graph->first;
+        if (graph->first)
+                ((xlator_t *)graph->first)->prev = xl;
+        graph->first = xl;
+
+        graph->xl_count++;
+}
+
+
+int
 glusterfs_graph_insert (glusterfs_graph_t *graph, glusterfs_ctx_t *ctx,
                         const char *type, const char *name)
 {
         xlator_t        *ixl = NULL;
-        xlator_list_t   *xlchild = NULL;
-        xlator_list_t   *xlparent = NULL;
 
         if (!ctx->master) {
                 gf_log ("glusterfs", GF_LOG_ERROR,
@@ -160,32 +202,11 @@ glusterfs_graph_insert (glusterfs_graph_t *graph, glusterfs_ctx_t *ctx,
                 return -1;
         }
 
-
-        /* children */
-        xlchild = GF_CALLOC (sizeof (*xlchild), 1, gf_common_mt_xlator_list_t);
-        if (!xlchild)
+        if (glusterfs_xlator_link (ixl, graph->top) == -1)
                 goto err;
-        xlchild->xlator = graph->top;
-        ixl->children = xlchild; xlchild = NULL;
-
-
-        /* parent */
-        xlparent = GF_CALLOC (sizeof (*xlparent), 1,
-                              gf_common_mt_xlator_list_t);
-        if (!xlparent)
-                goto err;
-        xlparent->xlator = ixl;
-
-        ixl->next = graph->first;
-        graph->first = ixl;
-
-        xlparent->next = ((xlator_t *)graph->top)->parents;
-        ((xlator_t *)graph->top)->parents = xlparent;
-
+        glusterfs_graph_set_first (graph, ixl);
         graph->top = ixl;
 
-        graph->xl_count++;
-
         return 0;
 err:
         xlator_destroy (ixl);
diff --git a/libglusterfs/src/graph.y b/libglusterfs/src/graph.y
index 14afaae64..19dfff0fd 100644
--- a/libglusterfs/src/graph.y
+++ b/libglusterfs/src/graph.y
@@ -30,6 +30,7 @@
 #include <sys/wait.h>
 
 #include "xlator.h"
+#include "graph-utils.h"
 #include "logging.h"
 
 static int new_volume (char *name);
@@ -270,9 +271,6 @@ volume_sub (char *sub)
 {
         extern int       yylineno;
         xlator_t        *trav = NULL;
-        xlator_list_t   *xlchild = NULL;
-        xlator_list_t   *tmp = NULL;
-        xlator_list_t   *xlparent = NULL;
         int              ret = 0;
 
         if (!sub) {
@@ -306,45 +304,13 @@ volume_sub (char *sub)
                 goto out;
         }
 
-        xlparent = (void *) GF_CALLOC (1, sizeof (*xlparent),
-                                       gf_common_mt_xlator_list_t);
-
-        if (!xlparent) {
-                gf_log ("parser", GF_LOG_ERROR, "Out of memory");
-                ret = -1;
-                goto out;
-        }
-
-        xlparent->xlator = curr;
-
-        tmp = trav->parents;
-        if (tmp == NULL) {
-                trav->parents = xlparent;
-        } else {
-                while (tmp->next)
-                        tmp = tmp->next;
-                tmp->next = xlparent;
-        }
-
-        xlchild = (void *) GF_CALLOC (1, sizeof(*xlchild),
-                                      gf_common_mt_xlator_list_t);
-        if (!xlchild) {
+	ret = glusterfs_xlator_link (curr, trav);
+	if (ret) {
                 gf_log ("parser", GF_LOG_ERROR, "Out of memory");
                 ret = -1;
                 goto out;
         }
 
-        xlchild->xlator = trav;
-
-        tmp = curr->children;
-        if (tmp == NULL) {
-                curr->children = xlchild;
-        } else {
-                while (tmp->next)
-                        tmp = tmp->next;
-                tmp->next = xlchild;
-        }
-
         gf_log ("parser", GF_LOG_TRACE, "child:%s->%s", curr->name, sub);
 
 out: