Clean up how a view's base table is defined

[empserver] / src / lib / common / file.c

diff --git a/src/lib/common/file.c b/src/lib/common/file.c
index 31ecc260b888729b0437afbd123839e50cb28fa7..d6db60fd9e00e2bcc88b1c178c78d94abe4cf0fb 100644 (file)
--- a/src/lib/common/file.c
+++ b/src/lib/common/file.c
@@ -83,7 +83,7 @@ ef_open(int type, int how, int nelt)
 
     /* open file */
     ep = &empfile[type];
-    if (CANT_HAPPEN(ep->fd >= 0))
+    if (CANT_HAPPEN(!ep->file || ep->base != EF_BAD || ep->fd >= 0))
        return 0;
     oflags = O_RDWR;
     if (how & EFF_PRIVATE)
@@ -220,20 +220,28 @@ ef_realloc_cache(struct empfile *ep, int count)
 }
 
 /*
- * Open the table TYPE as view of table BASE.
+ * Open the table TYPE, which is a view of a base table
+ * The table must not be already open.
  * Return non-zero on success, zero on failure.
- * Beware: views work only as long as BASE doesn't change size!
- * You must call ef_close(TYPE) before closing BASE.
+ * Beware: views work only as long as the base table doesn't change size!
+ * You must close the view before closing its base table.
  */
 int
-ef_open_view(int type, int base)
+ef_open_view(int type)
 {
     struct empfile *ep;
+    int base;
 
-    if (CANT_HAPPEN(!EF_IS_VIEW(type)))
-       return -1;
+    if (ef_check(type) < 0)
+       return 0;
     ep = &empfile[type];
-    if (CANT_HAPPEN(!(ef_flags(base) & EFF_MEM)))
+    base = ep->base;
+    if (ef_check(base) < 0)
+       return 0;
+    if (CANT_HAPPEN(!(ef_flags(base) & EFF_MEM)
+                   || ep->file || ep->size != empfile[base].size
+                   || ep->cache || ep->oninit || ep->postread
+                   || ep->prewrite || ep->onresize))
        return -1;
 
     ep->cache = empfile[base].cache;
@@ -520,11 +528,12 @@ ef_write(int type, int id, void *from)
     ep = &empfile[type];
     if (CANT_HAPPEN((ep->flags & (EFF_MEM | EFF_PRIVATE)) == EFF_PRIVATE))
        return 0;
-    if (CANT_HAPPEN((ep->flags & EFF_MEM) ? id >= ep->fids : id > ep->fids))
-       return 0;               /* not implemented */
     new_seqno(ep, from);
     if (id >= ep->fids) {
-       /* write beyond end of file extends it, take note */
+       /* beyond end of file */
+       if (CANT_HAPPEN((ep->flags & EFF_MEM) || id > ep->fids))
+           return 0;           /* not implemented */
+       /* write at end of file extends it */
        ep->fids = id + 1;
        if (ep->onresize)
            ep->onresize(type);