options: use &str over String where possible

I had been avoiding this as it means that we have to use
some explicit lifetimes, but all-in-all using explicit lifetimes
turned out not to be too bad and made the code overall a bit
cleaner and easier to understand.

Should see minor performance and memory usage gains from this
change.

Signed-off-by: Paul Osborne <[email protected]>

Author: posborne

src/commands/gpio_export.rs

@@ -12,7 +12,7 @@ use std::process::exit;
 use export;
 
 pub fn main(config: &GpioConfig, opts: &GpioExportOptions) {
-    let pin = match config.get_pin(&opts.pin[..]) {
+    let pin = match config.get_pin(opts.pin) {
         Some(pin) => pin,
         None => {
             println!("Unable to find config entry for pin '{}'", opts.pin);
@@ -21,7 +21,7 @@ pub fn main(config: &GpioConfig, opts: &GpioExportOptions) {
     };
 
     let symlink_root = match opts.symlink_root {
-        Some(ref slr) => &slr[..],
+        Some(slr) => slr,
         None => config.get_symlink_root(),
     };
 

src/commands/gpio_exportall.rs

@@ -13,7 +13,7 @@ use export;
 
 pub fn main(config: &GpioConfig, opts: &GpioExportAllOptions) {
     let symlink_root = match opts.symlink_root {
-        Some(ref slr) => &slr[..],
+        Some(slr) => slr,
         None => config.get_symlink_root(),
     };
 

src/commands/gpio_poll.rs

@@ -13,15 +13,15 @@ use std::process::exit;
 
 pub fn main(config: &GpioConfig, opts: &GpioPollOptions) {
     let timeout = opts.timeout.unwrap_or(-1);
-    let pin_config = match config.get_pin(&opts.pin[..]) {
+    let pin_config = match config.get_pin(opts.pin) {
         Some(pin) => pin,
         None => {
             println!("Unable to find config entry for pin '{}'", opts.pin);
             exit(1)
         }
     };
     let pin = pin_config.get_pin();
-    let edge = match &opts.edge[..] {
+    let edge = match opts.edge {
         "rising" => Edge::RisingEdge,
         "falling" => Edge::FallingEdge,
         "both" => Edge::BothEdges,

src/commands/gpio_read.rs

@@ -11,7 +11,7 @@ use config::GpioConfig;
 use std::process::exit;
 
 pub fn main(config: &GpioConfig, opts: &GpioReadOptions) {
-    let pin_config = match config.get_pin(&opts.pin[..]) {
+    let pin_config = match config.get_pin(opts.pin) {
         Some(pin) => pin,
         None => {
             println!("Unable to find config entry for pin '{}'", opts.pin);

src/commands/gpio_status.rs

@@ -15,7 +15,7 @@ use std::process::exit;
 pub fn main(config: &GpioConfig, opts: &GpioStatusOptions) {
     match opts.pin {
         Some(ref pin_name) => {
-            let pin_config = match config.get_pin(&pin_name[..]) {
+            let pin_config = match config.get_pin(pin_name) {
                 Some(pin) => pin,
                 None => {
                     println!("Unable to find config entry for pin '{}'", pin_name);

src/commands/gpio_unexport.rs

@@ -12,13 +12,13 @@ use std::process::exit;
 use export;
 
 pub fn main(config: &GpioConfig, opts: &GpioUnexportOptions) {
-    let pin_config = config.get_pin(&opts.pin[..]).unwrap_or_else(|| {
+    let pin_config = config.get_pin(opts.pin).unwrap_or_else(|| {
         println!("Unable to find config entry for pin '{}'", opts.pin);
         exit(1)
     });
 
     let symlink_root = match opts.symlink_root {
-        Some(ref slr) => &slr[..],
+        Some(slr) => slr,
         None => config.get_symlink_root(),
     };
 

src/commands/gpio_unexportall.rs

@@ -13,7 +13,7 @@ use export;
 
 pub fn main(config: &GpioConfig, opts: &GpioUnexportAllOptions) {
     let symlink_root = match opts.symlink_root {
-        Some(ref slr) => &slr[..],
+        Some(slr) => slr,
         None => config.get_symlink_root(),
     };
 

src/commands/gpio_write.rs

@@ -12,7 +12,7 @@ use std::process::exit;
 use sysfs_gpio::Direction;
 
 pub fn main(config: &GpioConfig, opts: &GpioWriteOptions) {
-    let pin_config = match config.get_pin(&opts.pin[..]) {
+    let pin_config = match config.get_pin(opts.pin) {
         Some(pin) => pin,
         None => {
             println!("Unable to find config entry for pin '{}'", opts.pin);

src/main.rs

@@ -154,7 +154,7 @@ fn main() {
         ("read", Some(m)) => {
             let read_options = GpioReadOptions {
                 gpio_opts: gpio_options,
-                pin: String::from(m.value_of("pin").unwrap()),
+                pin: m.value_of("pin").unwrap(),
             };
             gpio_read::main(&cfg, &read_options);
         }
@@ -167,16 +167,16 @@ fn main() {
             });
             let poll_options = GpioPollOptions {
                 gpio_opts: gpio_options,
-                edge: String::from(m.value_of("edge").unwrap_or("both")),
+                edge: m.value_of("edge").unwrap_or("both"),
                 timeout: timeout,
-                pin: String::from(m.value_of("pin").unwrap()),
+                pin: m.value_of("pin").unwrap(),
             };
             gpio_poll::main(&cfg, &poll_options);
         }
         ("write", Some(m)) => {
             let write_options = GpioWriteOptions {
                 gpio_opts: gpio_options,
-                pin: String::from(m.value_of("pin").unwrap()),
+                pin: m.value_of("pin").unwrap(),
                 value: match m.value_of("value").unwrap().parse::<u8>() {
                     Ok(value) => value,
                     Err(_) => {
@@ -191,9 +191,9 @@ fn main() {
         ("export", Some(m)) => {
             let export_options = GpioExportOptions {
                 gpio_opts: gpio_options,
-                pin: String::from(m.value_of("pin").unwrap()),
+                pin: m.value_of("pin").unwrap(),
                 symlink_root: match m.value_of("symlink-root") {
-                    Some(slr) => Some(String::from(slr)),
+                    Some(slr) => Some(slr),
                     None => None,
                 },
             };
@@ -203,7 +203,7 @@ fn main() {
             let exportall_options = GpioExportAllOptions {
                 gpio_opts: gpio_options,
                 symlink_root: match m.value_of("symlink-root") {
-                    Some(slr) => Some(String::from(slr)),
+                    Some(slr) => Some(slr),
                     None => None,
                 },
             };
@@ -212,22 +212,22 @@ fn main() {
         ("unexport", Some(m)) => {
             let unexport_options = GpioUnexportOptions {
                 gpio_opts: gpio_options,
-                pin: String::from(m.value_of("pin").unwrap()),
-                symlink_root: m.value_of("symlink-root").map(String::from),
+                pin: m.value_of("pin").unwrap(),
+                symlink_root: m.value_of("symlink-root"),
             };
             gpio_unexport::main(&cfg, &unexport_options);
         }
         ("unexport-all", Some(m)) => {
             let unexportall_options = GpioUnexportAllOptions {
                 gpio_opts: gpio_options,
-                symlink_root: m.value_of("symlink-root").map(String::from),
+                symlink_root: m.value_of("symlink-root"),
             };
             gpio_unexportall::main(&cfg, &unexportall_options);
         }
         ("status", Some(m)) => {
             let status_options = GpioStatusOptions {
                 gpio_opts: gpio_options,
-                pin: m.value_of("pin").map(String::from),
+                pin: m.value_of("pin"),
             };
             gpio_status::main(&cfg, &status_options);
         }

src/options.rs

@@ -12,54 +12,54 @@ pub struct GpioOptions {
 }
 
 #[derive(Debug)]
-pub struct GpioReadOptions {
+pub struct GpioReadOptions<'a> {
     pub gpio_opts: GpioOptions,
-    pub pin: String,
+    pub pin: &'a str,
 }
 
 #[derive(Debug)]
-pub struct GpioWriteOptions {
+pub struct GpioWriteOptions<'a> {
     pub gpio_opts: GpioOptions,
-    pub pin: String,
+    pub pin: &'a str,
     pub value: u8,
 }
 
 #[derive(Debug)]
-pub struct GpioPollOptions {
+pub struct GpioPollOptions<'a> {
     pub gpio_opts: GpioOptions,
     pub timeout: Option<isize>,
-    pub edge: String,
-    pub pin: String,
+    pub edge: &'a str,
+    pub pin: &'a str,
 }
 
 #[derive(Debug)]
-pub struct GpioExportOptions {
+pub struct GpioExportOptions<'a> {
     pub gpio_opts: GpioOptions,
-    pub symlink_root: Option<String>,
-    pub pin: String,
+    pub symlink_root: Option<&'a str>,
+    pub pin: &'a str,
 }
 
 #[derive(Debug)]
-pub struct GpioExportAllOptions {
+pub struct GpioExportAllOptions<'a> {
     pub gpio_opts: GpioOptions,
-    pub symlink_root: Option<String>,
+    pub symlink_root: Option<&'a str>,
 }
 
 #[derive(Debug)]
-pub struct GpioUnexportOptions {
+pub struct GpioUnexportOptions<'a> {
     pub gpio_opts: GpioOptions,
-    pub symlink_root: Option<String>,
-    pub pin: String,
+    pub symlink_root: Option<&'a str>,
+    pub pin: &'a str,
 }
 
 #[derive(Debug)]
-pub struct GpioUnexportAllOptions {
+pub struct GpioUnexportAllOptions<'a> {
     pub gpio_opts: GpioOptions,
-    pub symlink_root: Option<String>,
+    pub symlink_root: Option<&'a str>,
 }
 
 #[derive(Debug)]
-pub struct GpioStatusOptions {
+pub struct GpioStatusOptions<'a> {
     pub gpio_opts: GpioOptions,
-    pub pin: Option<String>,
+    pub pin: Option<&'a str>,
 }