a9fde73d32daf74780765442de44324061b01d66
markd
  Sun Jan 22 22:13:52 2023 -0800
Add URL resolver plugin functionality to allow an external program to convert
cloud URLs (s3:, gs: drs:, or really any non-HTTP RUL) to http/https URLs.
This can include signed URLs.  The cloud URL is used to index the UDC cache
rather than the resolved URL.  This allows for re-resolving signed URLs
if they time out.

Joint work by Max and Markd

diff --git src/htslib/hfile_net.c src/htslib/hfile_net.c
index d6452d1..ded19fc 100644
--- src/htslib/hfile_net.c
+++ src/htslib/hfile_net.c
@@ -1,113 +1,114 @@
 /*  hfile_net.c -- network backend for low-level input/output streams.
 
     Copyright (C) 2013-2015 Genome Research Ltd.
 
     Author: John Marshall <jm18@sanger.ac.uk>
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
 in the Software without restriction, including without limitation the rights
 to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 copies of the Software, and to permit persons to whom the Software is
 furnished to do so, subject to the following conditions:
 
 The above copyright notice and this permission notice shall be included in
 all copies or substantial portions of the Software.
 
 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 DEALINGS IN THE SOFTWARE.  */
 
 #include <config.h>
 
 #include <stdlib.h>
 #include <errno.h>
 
 #include "hfile_internal.h"
 
 #include "htslib/knetfile.h"
 
 typedef struct {
     hFILE base;
     knetFile *netfp;
 } hFILE_net;
 
 static int net_inited = 0;
 
 #ifdef _WIN32
 static void net_exit(void)
 {
     knet_win32_destroy();
 }
 #endif
 
 static int net_init(void)
 {
 #ifdef _WIN32
     if (knet_win32_init() != 0) return -1;
 
     // In the unlikely event atexit() fails, it's better to succeed here and
     // carry on and do the I/O; then eventually when the program exits, we'll
     // merely have failed to clean up properly, as if we had aborted.
     (void) atexit(net_exit);
 #endif
 
     net_inited = 1;
     return 0;
 }
 
 static ssize_t net_read(hFILE *fpv, void *buffer, size_t nbytes)
 {
     hFILE_net *fp = (hFILE_net *) fpv;
     return knet_read(fp->netfp, buffer, nbytes);
 }
 
 static off_t net_seek(hFILE *fpv, off_t offset, int whence)
 {
     hFILE_net *fp = (hFILE_net *) fpv;
     return knet_seek(fp->netfp, offset, whence);
 }
 
 static int net_close(hFILE *fpv)
 {
     hFILE_net *fp = (hFILE_net *) fpv;
     return knet_close(fp->netfp);
 }
 
 static const struct hFILE_backend net_backend =
 {
     net_read, NULL, net_seek, NULL, net_close
 };
 
 hFILE *hopen_net(const char *filename, const char *mode)
 {
     hFILE_net *fp;
 
     // Do any networking initialisation if this is the first use.
     if (! net_inited) { if (net_init() < 0) return NULL; }
 
     fp = (hFILE_net *) hfile_init(sizeof (hFILE_net), mode, 0);
     if (fp == NULL) return NULL;
 
     fp->netfp = knet_open(filename, mode);
     if (fp->netfp == NULL) { hfile_destroy((hFILE *) fp); return NULL; }
 
     fp->base.backend = &net_backend;
     return &fp->base;
 }
 
 int hfile_plugin_init_net(struct hFILE_plugin *self)
 {
     static const struct hFILE_scheme_handler handler =
         { hopen_net, hfile_always_remote, "knetfile", 0 };
 
     self->name = "knetfile";
     hfile_add_scheme_handler("https", &handler);
     hfile_add_scheme_handler("http", &handler);
     hfile_add_scheme_handler("ftp",  &handler);
+    hfile_add_scheme_handler("drs",  &handler);
     return 0;
 }