Consolidate separate print_config functions

src/lib.rs

@@ -155,7 +155,7 @@ pub extern "C" fn rust_main(_argc: c_int, _argv: *const *const c_char) -> c_int
     let filename = "device.conf";
     println!("Print configuration to file '{}.", filename);
 
-    radio::print_config(&device, filename);
+    radio::print_config(&device, Some(filename));
 
   } else if csv_flag {
     if matches.free.len() != 1 {
@@ -170,7 +170,7 @@ pub extern "C" fn rust_main(_argc: c_int, _argv: *const *const c_char) -> c_int
       print_usage();
     }
     let device = radio::read_image(&matches.free[0]);
-    radio::print_config_to_stdout(&device);
+    radio::print_config(&device, None);
   }
 
   exit(0);

src/radio.rs

@@ -310,32 +310,38 @@ pub fn parse_config(radio: &Radio, filename: &str) {
 }
 
 /// Print full information about the device configuration.
-pub fn print_config(radio: &Radio, filename: &str) {
+/// If `filename` is `None`, write to stdout.
+pub fn print_config(radio: &Radio, filename: Option<&str>) {
+
+  let file;
+
+  let (fd, verbosity) = match filename {
+    None => {
+      unsafe {
+        let verbosity = if libc::isatty(libc::STDOUT_FILENO) == 1 {
+          0
+        } else {
+          1
+        };
+        (libc::STDOUT_FILENO, verbosity)
+      }
+    },
+    Some(filename) => {
+      file = std::fs::File::create(filename).unwrap();
+      (file.as_raw_fd(), 1)
+    }
+  };
+
   let device = radio.ptr;
-  let file = std::fs::File::create(filename).unwrap();
-  let fd = file.as_raw_fd();
   let mode = CString::new("w").unwrap();
+
   unsafe {
     let file = libc::fdopen(fd, mode.as_ptr());
-    radio_print_config(device, file, 1);
+    radio_print_config(device, file, verbosity);
     libc::fclose(file);
   }
 }
 
-pub fn print_config_to_stdout(radio: &Radio) {
-  let device = radio.ptr;
-  let mode = CString::new("w").unwrap();
-  unsafe {
-    let stdout = libc::fdopen(libc::STDOUT_FILENO, mode.as_ptr());
-    let verbosity = if libc::isatty(libc::STDOUT_FILENO) == 1 {
-      0
-    } else {
-      1
-    };
-    radio_print_config(device, stdout, verbosity);
-  }
-}
-
 /// Print generic information about the device.
 pub fn print_version(radio: &Radio) {
   let device = radio.ptr as *mut radio_device_t;