xap_helper: implement mset endpoint for WWW, IMAP, etc...

The C++ version will allow us to take full advantage of Xapian's
APIs for better queries, and the Perl bindings version can still
be advantageous in the future since we'll be able to support
timeouts effectively.

1 files changed, 11 insertions, 26 deletions

diff --git a/lib/PublicInbox/xh_cidx.h b/lib/PublicInbox/xh_cidx.h
index c2d94162..1980f9f6 100644
--- a/lib/PublicInbox/xh_cidx.h
+++ b/lib/PublicInbox/xh_cidx.h
@@ -107,8 +107,7 @@ static bool root2offs_str(struct fbuf *root_offs, Xapian::Document *doc)
                 fputs((const char *)ep->data, root_offs->fp);
         }
         fputc('\n', root_offs->fp);
-        if (ferror(root_offs->fp) | fclose(root_offs->fp))
-                err(EXIT_FAILURE, "ferror|fclose(root_offs)"); // ENOMEM
+        ERR_CLOSE(root_offs->fp, EXIT_FAILURE); // ENOMEM
         root_offs->fp = NULL;
         return true;
 }
@@ -138,38 +137,24 @@ static void dump_roots_term(struct req *req, const char *pfx,
 // buffering and rely on flock(2), here
 static bool dump_roots_flush(struct req *req, struct dump_roots_tmp *drt)
 {
-        char *p;
-        int fd = fileno(req->fp[0]);
         bool ok = true;
+        off_t off = ftello(drt->wbuf.fp);
+        if (off < 0) EABORT("ftello");
+        if (!off) return ok;
+
+        ERR_FLUSH(drt->wbuf.fp); // ENOMEM
+        int fd = fileno(req->fp[0]);
 
-        if (!drt->wbuf.fp) return true;
-        if (fd < 0) EABORT("BUG: fileno");
-        if (ferror(drt->wbuf.fp) | fclose(drt->wbuf.fp)) // ENOMEM?
-                err(EXIT_FAILURE, "ferror|fclose(drt->wbuf.fp)");
-        drt->wbuf.fp = NULL;
-        if (!drt->wbuf.len) goto done_free;
         while (flock(drt->root2off_fd, LOCK_EX)) {
                 if (errno == EINTR) continue;
                 err(EXIT_FAILURE, "LOCK_EX"); // ENOLCK?
         }
-        p = drt->wbuf.ptr;
-        do { // write to client FD
-                ssize_t n = write(fd, p, drt->wbuf.len);
-                if (n > 0) {
-                        drt->wbuf.len -= n;
-                        p += n;
-                } else {
-                        perror(n ? "write" : "write (zero bytes)");
-                        return false;
-                }
-        } while (drt->wbuf.len);
+        ok = write_all(fd, &drt->wbuf, (size_t)off);
         while (flock(drt->root2off_fd, LOCK_UN)) {
                 if (errno == EINTR) continue;
                 err(EXIT_FAILURE, "LOCK_UN"); // ENOLCK?
         }
-done_free: // OK to skip on errors, dump_roots_ensure calls fbuf_ensure
-        free(drt->wbuf.ptr);
-        drt->wbuf.ptr = NULL;
+        if (fseeko(drt->wbuf.fp, 0, SEEK_SET)) EABORT("fseeko");
         return ok;
 }
 
@@ -238,11 +223,11 @@ static bool cmd_dump_roots(struct req *req)
         req->sort_col = -1;
         Xapian::MSet mset = commit_mset(req, req->argv[optind + 1]);
 
+        fbuf_init(&drt.wbuf);
+
         // @UNIQ_FOLD in CodeSearchIdx.pm can handle duplicate lines fine
         // in case we need to retry on DB reopens
         for (Xapian::MSetIterator i = mset.begin(); i != mset.end(); i++) {
-                if (!drt.wbuf.fp)
-                        fbuf_init(&drt.wbuf);
                 for (int t = 10; t > 0; --t)
                         switch (dump_roots_iter(req, &drt, &i)) {
                         case ITER_OK: t = 0; break; // leave inner loop