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, 35 insertions, 20 deletions

diff --git a/src/tool_operate.c b/src/tool_operate.c
index 8a5569bd8..6d02fb667 100644
--- a/src/tool_operate.c
+++ b/src/tool_operate.c
@@ -586,8 +586,9 @@ int operate(struct Configurable *config, int argc, argv_item_t argv[])
           }
         }
 
-        if((urlnode->flags&GETOUT_USEREMOTE) ||
-           (outfile && !curlx_strequal("-", outfile)) ) {
+        if(((urlnode->flags&GETOUT_USEREMOTE) ||
+            (outfile && !curlx_strequal("-", outfile))) &&
+           (metalink || !config->use_metalink)) {
 
           /*
            * We have specified a file name to store the result in, or we have
@@ -826,8 +827,15 @@ int operate(struct Configurable *config, int argc, argv_item_t argv[])
 
         /* where to store */
         my_setopt(curl, CURLOPT_WRITEDATA, &outs);
-        /* what call to write */
-        my_setopt(curl, CURLOPT_WRITEFUNCTION, tool_write_cb);
+        if(metalink || !config->use_metalink)
+          /* what call to write */
+          my_setopt(curl, CURLOPT_WRITEFUNCTION, tool_write_cb);
+#ifdef USE_METALINK
+        else
+          /* Set Metalink specific write callback function to parse
+             XML data progressively. */
+          my_setopt(curl, CURLOPT_WRITEFUNCTION, metalink_write_cb);
+#endif /* USE_METALINK */
 
         /* for uploads */
         input.fd = infd;
@@ -1316,6 +1324,19 @@ int operate(struct Configurable *config, int argc, argv_item_t argv[])
 #endif
 
         for(;;) {
+#ifdef USE_METALINK
+          if(!metalink && config->use_metalink) {
+            /* If outs.metalink_parser is non-NULL, delete it first. */
+            if(outs.metalink_parser)
+              metalink_parser_context_delete(outs.metalink_parser);
+            outs.metalink_parser = metalink_parser_context_new();
+            if(outs.metalink_parser == NULL) {
+              res = CURLE_OUT_OF_MEMORY;
+              goto show_error;
+            }
+          }
+#endif /* USE_METALINK */
+
           res = curl_easy_perform(curl);
 
           if(outs.is_cd_filename && outs.stream && !config->mute &&
@@ -1569,22 +1590,12 @@ int operate(struct Configurable *config, int argc, argv_item_t argv[])
 #endif
 
 #ifdef USE_METALINK
-        if(!metalink && res == CURLE_OK && outs.filename) {
-          /* Check the content-type header field and if it indicates
-             Metalink file, parse it and add getout for them. */
-          char *content_type;
-          curl_easy_getinfo(curl, CURLINFO_CONTENT_TYPE, &content_type);
-          if(content_type && check_metalink_content_type(content_type)) {
-            if(!(config->mute)) {
-              fprintf(config->errors, "\nParsing Metalink file: %s\n",
-                      outs.filename);
-            }
-            if(parse_metalink(config, outs.filename) == 0)
-              fprintf(config->errors,
-                      "Metalink file is parsed successfully\n");
-            else
-              fprintf(config->errors, "Could not parse Metalink file.\n");
-          }
+        if(!metalink && config->use_metalink && res == CURLE_OK) {
+          if(parse_metalink(config, &outs) == 0)
+            fprintf(config->errors,
+                    "Metalink XML is parsed successfully\n");
+          else
+            fprintf(config->errors, "Could not parse Metalink XML.\n");
         }
         else if(metalink && res == CURLE_OK && !metalink_next_res) {
           int rv = metalink_check_hash(config, mlfile, outs.filename);
@@ -1597,6 +1608,10 @@ int operate(struct Configurable *config, int argc, argv_item_t argv[])
         /* No more business with this output struct */
         if(outs.alloc_filename)
           Curl_safefree(outs.filename);
+#ifdef USE_METALINK
+        if(outs.metalink_parser)
+          metalink_parser_context_delete(outs.metalink_parser);
+#endif /* USE_METALINK */
         memset(&outs, 0, sizeof(struct OutStruct));
         hdrcbdata.outs = NULL;