moved download to sip tool

src/tasks/sip.cpp

@@ -121,20 +121,9 @@ void sip::download()
 		}
 	}
 
-	run_tool(process_runner(process()
-		.binary(python::python_exe())
-		.chcp(65001)
-		.stdout_encoding(encodings::utf8)
-		.stderr_encoding(encodings::utf8)
-		.arg("-X", "utf8")
-		.arg("-m", "pip")
-		.arg("download")
-		.arg("--no-binary=:all:")
-		.arg("--no-deps")
-		.arg("-d", paths::cache())
-		.arg("sip==" + version())
-		.env(this_env::get()
-			.set("PYTHONUTF8", "1"))));
+	run_tool(pip(pip::download)
+		.package("sip")
+		.version(version()));
 }
 
 void sip::generate()

src/tools/tools.cpp

@@ -265,6 +265,10 @@ void pip::do_run()
 			do_install();
 			break;
 
+		case download:
+			do_download();
+			break;
+
 		default:
 			cx().bail_out(context::generic, "pip unknown op {}", op_);
 	}
@@ -343,6 +347,26 @@ void pip::do_install()
 	execute_and_join();
 }
 
+void pip::do_download()
+{
+	set_process(process()
+		.binary(python::python_exe())
+		.chcp(65001)
+		.stdout_encoding(encodings::utf8)
+		.stderr_encoding(encodings::utf8)
+		.arg("-X", "utf8")
+		.arg("-m", "pip")
+		.arg("download")
+		.arg("--no-binary=:all:")
+		.arg("--no-deps")
+		.arg("-d", paths::cache())
+		.arg(package_ + "==" + version_)
+		.env(this_env::get()
+			.set("PYTHONUTF8", "1")));
+
+	execute_and_join();
+}
+
 
 transifex::transifex(ops o) :
 	basic_process_runner("transifex"), op_(o),

src/tools/tools.h

@@ -596,7 +596,8 @@ public:
 	enum ops
 	{
 		ensure = 1,
-		install
+		install,
+		download
 	};
 
 	pip(ops o);
@@ -616,6 +617,7 @@ private:
 
 	void do_ensure();
 	void do_install();
+	void do_download();
 };