fix: support binary target in oras cp (#843)

Signed-off-by: Billy Zha <[email protected]>

cmd/oras/internal/option/remote.go

@@ -97,14 +97,11 @@ func (opts *Remote) ApplyFlagsWithPrefix(fs *pflag.FlagSet, prefix, description
 	fs.BoolVarP(&opts.Insecure, flagPrefix+"insecure", "", false, "allow connections to "+notePrefix+"SSL registry without certs")
 	fs.BoolVarP(&opts.PlainHTTP, flagPrefix+"plain-http", "", false, "allow insecure connections to "+notePrefix+"registry without SSL check")
 	fs.StringVarP(&opts.CACertFilePath, flagPrefix+"ca-file", "", "", "server certificate authority file for the remote "+notePrefix+"registry")
+	fs.StringArrayVarP(&opts.resolveFlag, flagPrefix+"resolve", "", nil, "customized DNS for "+notePrefix+"registry, formatted in `host:port:address[:address_port]`")
 
 	if fs.Lookup("registry-config") == nil {
 		fs.StringArrayVarP(&opts.Configs, "registry-config", "", nil, "`path` of the authentication file")
 	}
-
-	if fs.Lookup("resolve") == nil {
-		fs.StringArrayVarP(&opts.resolveFlag, "resolve", "", nil, "customized DNS formatted in `host:port:address[:address_port]`")
-	}
 }
 
 // Parse tries to read password with optional cmd prompt.

cmd/oras/internal/option/target.go

@@ -179,8 +179,9 @@ func (opts *Target) EnsureReferenceNotEmpty() error {
 // BinaryTarget struct contains flags and arguments specifying two registries or
 // image layouts.
 type BinaryTarget struct {
-	From Target
-	To   Target
+	From        Target
+	To          Target
+	resolveFlag []string
 }
 
 // EnableDistributionSpecFlag set distribution specification flag as applicable.
@@ -193,9 +194,13 @@ func (opts *BinaryTarget) EnableDistributionSpecFlag() {
 func (opts *BinaryTarget) ApplyFlags(fs *pflag.FlagSet) {
 	opts.From.ApplyFlagsWithPrefix(fs, "from", "source")
 	opts.To.ApplyFlagsWithPrefix(fs, "to", "destination")
+	fs.StringArrayVarP(&opts.resolveFlag, "resolve", "", nil, "base DNS rules formatted in `host:port:address[:address_port]` for --from-resolve and --to-resolve")
 }
 
 // Parse parses user-provided flags and arguments into option struct.
 func (opts *BinaryTarget) Parse() error {
+	// resolve are parsed in array order, latter will overwrite former
+	opts.From.resolveFlag = append(opts.resolveFlag, opts.From.resolveFlag...)
+	opts.To.resolveFlag = append(opts.resolveFlag, opts.To.resolveFlag...)
 	return Parse(opts)
 }