feat(abigen): add --contract flag to specify a given contract (#334)

* add contract flag

* Use GlobalXX

* Update cmd/abigen/main.go

Co-authored-by: Péter Garamvölgyi <th307q@gmail.com>

* Update cmd/abigen/main.go

Co-authored-by: Péter Garamvölgyi <th307q@gmail.com>

---------

Co-authored-by: Péter Garamvölgyi <th307q@gmail.com>
Co-authored-by: HAOYUatHZ <37070449+HAOYUatHZ@users.noreply.github.com>

cmd/abigen/main.go

@@ -99,6 +99,10 @@ var (
 		Name:  "alias",
 		Usage: "Comma separated aliases for function and event renaming, e.g. original1=alias1, original2=alias2",
 	}
+	contractFlag = cli.StringFlag{
+		Name:  "contract",
+		Usage: "Name of the contract to generate the bindings for",
+	}
 )
 
 func init() {
@@ -117,6 +121,7 @@ func init() {
 		outFlag,
 		langFlag,
 		aliasFlag,
+		contractFlag,
 	}
 	app.Action = utils.MigrateFlags(abigen)
 	cli.CommandHelpTemplate = flags.OriginCommandHelpTemplate
@@ -225,6 +230,13 @@ func abigen(c *cli.Context) error {
 		}
 		// Gather all non-excluded contract for binding
 		for name, contract := range contracts {
+			// The fully qualified name is of the form <solFilePath>:<type>
+			nameParts := strings.Split(name, ":")
+			typeName := nameParts[len(nameParts)-1]
+			// If a contract name is provided then ignore all other contracts
+			if c.GlobalIsSet(contractFlag.Name) && c.GlobalString(contractFlag.Name) != typeName {
+				continue
+			}
 			if exclude[strings.ToLower(name)] {
 				continue
 			}
@@ -235,11 +247,10 @@ func abigen(c *cli.Context) error {
 			abis = append(abis, string(abi))
 			bins = append(bins, contract.Code)
 			sigs = append(sigs, contract.Hashes)
-			nameParts := strings.Split(name, ":")
-			types = append(types, nameParts[len(nameParts)-1])
+			types = append(types, typeName)
 
 			libPattern := crypto.Keccak256Hash([]byte(name)).String()[2:36]
-			libs[libPattern] = nameParts[len(nameParts)-1]
+			libs[libPattern] = typeName
 		}
 	}
 	// Extract all aliases from the flags