[libgpiod][PATCH 14/16] bindings: rust: make request_config optional in Chip.request_lines()

[Bartosz Golaszewski <brgl@bgdev.pl>]

From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Request config is not necessary to request lines. In C API we accept
a NULL pointer, in C++ it's not necessary to assign a request_config
to the request builder, in Python the consumer and event buffer size
arguments are optional. Let's make rust bindings consistent and not
require the request config to be always present. Convert the argument
in request_lines to Option and update the rest of the code.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
---
 bindings/rust/libgpiod/examples/gpio_events.rs         |  2 +-
 .../libgpiod/examples/gpio_threaded_info_events.rs     |  2 +-
 bindings/rust/libgpiod/examples/gpioget.rs             |  2 +-
 bindings/rust/libgpiod/examples/gpiomon.rs             |  2 +-
 bindings/rust/libgpiod/examples/gpioset.rs             |  2 +-
 bindings/rust/libgpiod/src/chip.rs                     | 10 ++++++++--
 bindings/rust/libgpiod/tests/common/config.rs          |  2 +-
 bindings/rust/libgpiod/tests/info_event.rs             |  2 +-
 8 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/bindings/rust/libgpiod/examples/gpio_events.rs b/bindings/rust/libgpiod/examples/gpio_events.rs
index 04267d9..cbdf1b5 100644
--- a/bindings/rust/libgpiod/examples/gpio_events.rs
+++ b/bindings/rust/libgpiod/examples/gpio_events.rs
@@ -42,7 +42,7 @@ fn main() -> Result<()> {
     let rconfig = request::Config::new()?;
 
     let mut buffer = request::Buffer::new(1)?;
-    let request = chip.request_lines(&rconfig, &lconfig)?;
+    let request = chip.request_lines(Some(&rconfig), &lconfig)?;
 
     loop {
         match request.wait_edge_events(None) {
diff --git a/bindings/rust/libgpiod/examples/gpio_threaded_info_events.rs b/bindings/rust/libgpiod/examples/gpio_threaded_info_events.rs
index e17f0f0..367b2f6 100644
--- a/bindings/rust/libgpiod/examples/gpio_threaded_info_events.rs
+++ b/bindings/rust/libgpiod/examples/gpio_threaded_info_events.rs
@@ -40,7 +40,7 @@ fn request_reconfigure_line(
         let request = chip
             .lock()
             .unwrap()
-            .request_lines(&rconfig, &lconfig)
+            .request_lines(Some(&rconfig), &lconfig)
             .unwrap();
 
         // Signal the parent to continue
diff --git a/bindings/rust/libgpiod/examples/gpioget.rs b/bindings/rust/libgpiod/examples/gpioget.rs
index 6e60833..74baf30 100644
--- a/bindings/rust/libgpiod/examples/gpioget.rs
+++ b/bindings/rust/libgpiod/examples/gpioget.rs
@@ -37,7 +37,7 @@ fn main() -> Result<()> {
     let rconfig = request::Config::new()?;
     rconfig.set_consumer(&args[0])?;
 
-    let request = chip.request_lines(&rconfig, &lconfig)?;
+    let request = chip.request_lines(Some(&rconfig), &lconfig)?;
     let map = request.values()?;
 
     println!("{:?}", map);
diff --git a/bindings/rust/libgpiod/examples/gpiomon.rs b/bindings/rust/libgpiod/examples/gpiomon.rs
index f17a81f..a09ddfc 100644
--- a/bindings/rust/libgpiod/examples/gpiomon.rs
+++ b/bindings/rust/libgpiod/examples/gpiomon.rs
@@ -41,7 +41,7 @@ fn main() -> Result<()> {
     let rconfig = request::Config::new()?;
 
     let mut buffer = request::Buffer::new(1)?;
-    let request = chip.request_lines(&rconfig, &lconfig)?;
+    let request = chip.request_lines(Some(&rconfig), &lconfig)?;
 
     loop {
         match request.wait_edge_events(None) {
diff --git a/bindings/rust/libgpiod/examples/gpioset.rs b/bindings/rust/libgpiod/examples/gpioset.rs
index 875a3ad..6247996 100644
--- a/bindings/rust/libgpiod/examples/gpioset.rs
+++ b/bindings/rust/libgpiod/examples/gpioset.rs
@@ -54,7 +54,7 @@ fn main() -> Result<()> {
     let rconfig = request::Config::new()?;
     rconfig.set_consumer(&args[0])?;
 
-    chip.request_lines(&rconfig, &lconfig)?;
+    chip.request_lines(Some(&rconfig), &lconfig)?;
 
     // Wait for keypress, let user verify line status.
     stdin().read_exact(&mut [0u8]).unwrap();
diff --git a/bindings/rust/libgpiod/src/chip.rs b/bindings/rust/libgpiod/src/chip.rs
index 91b4c94..9c3c2b4 100644
--- a/bindings/rust/libgpiod/src/chip.rs
+++ b/bindings/rust/libgpiod/src/chip.rs
@@ -11,6 +11,7 @@ use std::cmp::Ordering;
 use std::ffi::{CStr, CString};
 use std::os::{raw::c_char, unix::prelude::AsRawFd};
 use std::path::Path;
+use std::ptr;
 use std::str;
 use std::sync::Arc;
 use std::time::Duration;
@@ -195,13 +196,18 @@ impl Chip {
     /// Request a set of lines for exclusive usage.
     pub fn request_lines(
         &self,
-        rconfig: &request::Config,
+        rconfig: Option<&request::Config>,
         lconfig: &line::Config,
     ) -> Result<request::Request> {
+        let req_cfg = match rconfig {
+            Some(cfg) => cfg.config,
+            _ => ptr::null(),
+        } as *mut gpiod::gpiod_request_config;
+
         // SAFETY: The `gpiod_line_request` returned by libgpiod is guaranteed to live as long
         // as the `struct Request`.
         let request = unsafe {
-            gpiod::gpiod_chip_request_lines(self.ichip.chip, rconfig.config, lconfig.config)
+            gpiod::gpiod_chip_request_lines(self.ichip.chip, req_cfg, lconfig.config)
         };
 
         if request.is_null() {
diff --git a/bindings/rust/libgpiod/tests/common/config.rs b/bindings/rust/libgpiod/tests/common/config.rs
index 842a70a..b838b66 100644
--- a/bindings/rust/libgpiod/tests/common/config.rs
+++ b/bindings/rust/libgpiod/tests/common/config.rs
@@ -106,7 +106,7 @@ impl TestConfig {
     pub(crate) fn request_lines(&mut self) -> Result<()> {
         let chip = Chip::open(&self.sim.lock().unwrap().dev_path())?;
 
-        self.request = Some(chip.request_lines(&self.rconfig, &self.lconfig)?);
+        self.request = Some(chip.request_lines(Some(&self.rconfig), &self.lconfig)?);
         self.chip = Some(chip);
 
         Ok(())
diff --git a/bindings/rust/libgpiod/tests/info_event.rs b/bindings/rust/libgpiod/tests/info_event.rs
index bfa0058..6bf7a0f 100644
--- a/bindings/rust/libgpiod/tests/info_event.rs
+++ b/bindings/rust/libgpiod/tests/info_event.rs
@@ -32,7 +32,7 @@ mod info_event {
             let request = chip
                 .lock()
                 .unwrap()
-                .request_lines(&rconfig, &lconfig1)
+                .request_lines(Some(&rconfig), &lconfig1)
                 .unwrap();
 
             // Signal the parent to continue
-- 
2.37.2