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 a95de92f521f2b6e33f6fbb8f00db9e9bef8248e..d6db60fd9e00e2bcc88b1c178c78d94abe4cf0fb 100644 (file)
--- a/src/lib/common/file.c
+++ b/src/lib/common/file.c
@@ -74,7 +74,7 @@ int
 ef_open(int type, int how, int nelt)
 {
     struct empfile *ep;
-    int oflags, fd, fsiz, nslots;
+    int oflags, fd, fsiz, fids, nslots;
 
     if (ef_check(type) < 0)
        return 0;
@@ -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)
@@ -104,10 +104,10 @@ ef_open(int type, int how, int nelt)
        close(fd);
        return 0;
     }
-    ep->fids = fsiz / ep->size;
-    if (nelt >= 0 && nelt != ep->fids) {
+    fids = fsiz / ep->size;
+    if (nelt >= 0 && nelt != fids) {
        logerror("Can't open %s (got %d records instead of %d)",
-                ep->file, ep->fids, nelt);
+                ep->file, fids, nelt);
        close(fd);
        return 0;
     }
@@ -116,9 +116,9 @@ ef_open(int type, int how, int nelt)
     if (ep->flags & EFF_STATIC) {
        /* ep->cache already points to space for ep->csize elements */
        if (how & EFF_MEM) {
-           if (ep->fids > ep->csize) {
-               logerror("Can't open %s: file larger than %d bytes",
-                        ep->file, ep->fids * ep->size);
+           if (fids > ep->csize) {
+               logerror("Can't open %s (file larger than %d records)",
+                        ep->file, ep->csize);
                close(fd);
                return 0;
            }
@@ -127,7 +127,7 @@ ef_open(int type, int how, int nelt)
        if (CANT_HAPPEN(ep->cache))
            free(ep->cache);
        if (how & EFF_MEM)
-           nslots = ep->fids;
+           nslots = fids;
        else
            nslots = blksize(fd) / ep->size;
        if (!ef_realloc_cache(ep, nslots)) {
@@ -138,21 +138,21 @@ ef_open(int type, int how, int nelt)
     }
     ep->baseid = 0;
     ep->cids = 0;
+    ep->fids = fids;
     ep->flags = (ep->flags & EFF_IMMUTABLE) | (how & ~EFF_CREATE);
     ep->fd = fd;
 
     /* map file into cache */
-    if ((how & EFF_MEM) && ep->fids) {
-       if (fillcache(ep, 0) != ep->fids) {
+    if ((how & EFF_MEM) && fids) {
+       if (fillcache(ep, 0) != fids) {
            ep->cids = 0;       /* prevent cache flush */
-           ep->flags &= EFF_IMMUTABLE; /* maintain invariant */
            ef_close(type);
            return 0;
        }
     }
 
-    if (ep->onresize && ep->onresize(type) < 0)
-       return 0;
+    if (ep->onresize)
+       ep->onresize(type);
     return 1;
 }
 
@@ -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;
@@ -246,7 +254,7 @@ ef_open_view(int type, int base)
 }
 
 /*
- * Close the file-backed table TYPE (EF_SECTOR, ...).
+ * Close the open table TYPE (EF_SECTOR, ...).
  * Return non-zero on success, zero on failure.
  */
 int
@@ -259,15 +267,16 @@ ef_close(int type)
        return 0;
     ep = &empfile[type];
 
-    if (EF_IS_VIEW(type))
+    if (EF_IS_VIEW(type)) {
        ep->cache = NULL;
-    else {
+       ep->csize = 0;
+    } else {
        if (!ef_flush(type))
            retval = 0;
-       ep->flags &= EFF_IMMUTABLE;
        if (!(ep->flags & EFF_STATIC)) {
            free(ep->cache);
            ep->cache = NULL;
+           ep->csize = 0;
        }
        if (close(ep->fd) < 0) {
            logerror("Error closing %s (%s)", ep->file, strerror(errno));
@@ -275,9 +284,10 @@ ef_close(int type)
        }
        ep->fd = -1;
     }
+    ep->flags &= EFF_IMMUTABLE;
     ep->baseid = ep->cids = ep->fids = 0;
-    if (ep->onresize && ep->onresize(type) < 0)
-       retval = 0;
+    if (ep->onresize)
+       ep->onresize(type);
     return retval;
 }
 
@@ -518,14 +528,15 @@ 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) < 0)
-           return 0;
+       if (ep->onresize)
+           ep->onresize(type);
     }
     if (id >= ep->baseid && id < ep->baseid + ep->cids) {
        cachep = ep->cache + (id - ep->baseid) * ep->size;
@@ -709,13 +720,13 @@ ef_extend(int type, int count)
        }
     }
     ep->fids = id + count;
-    if (ep->onresize && ep->onresize(type) < 0)
-       return 0;
+    if (ep->onresize)
+       ep->onresize(type);
     return 1;
 }
 
 /*
- * Initialize element ID for EP in BUF.
+ * Initialize element ID for table TYPE in BUF.
  * FIXME pass buffer size!
  * BUF is marked fresh with ef_mark_fresh().
  */
@@ -802,8 +813,8 @@ ef_truncate(int type, int count)
            ep->cids = count - ep->baseid;
     }
 
-    if (ep->onresize && ep->onresize(type) < 0)
-       return 0;
+    if (ep->onresize)
+       ep->onresize(type);
     return 1;
 }