curl: Made --metalink option toggle Metalink functionality

In this change, --metalink option no longer takes argument.  If
it is specified, given URIs are processed as Metalink XML file.
If given URIs are remote (e.g., http URI), curl downloads it
first. Regardless URI is local file (e.g., file URI scheme) or
remote, Metalink XML file is not written to local file system and
the received data is fed into Metalink XML parser directly.  This
means with --metalink option, filename related options like -O
and -o are ignored.

Usage examples:

$ curl --metalink http://example.org/foo.metalink

This will download foo.metalink and parse it and then download
the URI described there.

$ curl --metalink file://foo.metalink

This will parse local file foo.metalink and then download the URI
described there.

1 files changed, 40 insertions, 12 deletions

diff --git a/src/tool_metalink.c b/src/tool_metalink.c
index 8f6a1f870..74a0012ac 100644
--- a/src/tool_metalink.c
+++ b/src/tool_metalink.c
@@ -33,8 +33,6 @@
 #  include <fcntl.h>
 #endif
 
-#include <metalink/metalink_parser.h>
-
 #ifdef USE_SSLEAY
 #  ifdef USE_OPENSSL
 #    include <openssl/md5.h>
@@ -68,6 +66,7 @@
 #include "tool_paramhlp.h"
 #include "tool_cfgable.h"
 #include "tool_metalink.h"
+#include "tool_msgs.h"
 
 #include "memdebug.h" /* keep this as LAST include */
 
@@ -331,8 +330,8 @@ static int check_hash(const char *filename,
   digest_context *dctx;
   int check_ok;
   int fd;
-  fprintf(error, "Checking %s checksum of file %s\n", digest_def->hash_name,
-          filename);
+  fprintf(error, "Validating %s checksum (This may take some time)...\n",
+          digest_def->hash_name);
   fd = open(filename, O_RDONLY);
   if(fd == -1) {
     fprintf(error, "Could not open file %s: %s\n", filename, strerror(errno));
@@ -358,6 +357,12 @@ static int check_hash(const char *filename,
   Curl_digest_final(dctx, result);
   check_ok = memcmp(result, digest,
                     digest_def->dparams->digest_resultlen) == 0;
+  /* sha*sum style verdict output */
+  if(check_ok)
+    fprintf(error, "%s: OK\n", filename);
+  else
+    fprintf(error, "%s: FAILED\n", filename);
+
   free(result);
   close(fd);
   return check_ok;
@@ -373,12 +378,6 @@ int metalink_check_hash(struct Configurable *config,
   }
   rv = check_hash(filename, mlfile->checksum->digest_def,
                   mlfile->checksum->digest, config->errors);
-  if(rv == 1) {
-    fprintf(config->errors, "Checksum matched\n");
-  }
-  else if(rv == 0) {
-    fprintf(config->errors, "Checksum didn't match\n");
-  }
   return rv;
 }
 
@@ -468,13 +467,15 @@ static metalinkfile *new_metalinkfile(metalink_file_t *fileinfo)
   return f;
 }
 
-int parse_metalink(struct Configurable *config, const char *infile)
+int parse_metalink(struct Configurable *config, struct OutStruct *outs)
 {
   metalink_error_t r;
   metalink_t* metalink;
   metalink_file_t **files;
 
-  r = metalink_parse_file(infile, &metalink);
+  /* metlaink_parse_final deletes outs->metalink_parser */
+  r = metalink_parse_final(outs->metalink_parser, NULL, 0, &metalink);
+  outs->metalink_parser = NULL;
   if(r != 0) {
     return -1;
   }
@@ -531,6 +532,33 @@ int parse_metalink(struct Configurable *config, const char *infile)
   return 0;
 }
 
+size_t metalink_write_cb(void *buffer, size_t sz, size_t nmemb,
+                         void *userdata)
+{
+  struct OutStruct *outs = userdata;
+  struct Configurable *config = outs->config;
+  int rv;
+
+  /*
+   * Once that libcurl has called back tool_write_cb() the returned value
+   * is checked against the amount that was intended to be written, if
+   * it does not match then it fails with CURLE_WRITE_ERROR. So at this
+   * point returning a value different from sz*nmemb indicates failure.
+   */
+  const size_t failure = (sz * nmemb) ? 0 : 1;
+
+  if(!config)
+    return failure;
+
+  rv = metalink_parse_update(outs->metalink_parser, buffer, sz *nmemb);
+  if(rv == 0)
+    return sz * nmemb;
+  else {
+    warnf(config, "Failed to parse Metalink XML\n");
+    return failure;
+  }
+}
+
 /*
  * Returns nonzero if content_type includes mediatype.
  */