From 4a434a5e67f27eacf04273fdd297415198b80183 Mon Sep 17 00:00:00 2001
From: Andrey Zgarbul <zgarbul.andrey@gmail.com>
Date: Sat, 5 Oct 2024 13:03:36 +0300
Subject: [PATCH] Check device selected in build.rs

---
 CHANGELOG.md |  1 +
 Cargo.toml   | 13 +++++--------
 build.rs     | 36 ++++++++++++++++++++++++++++++++++++
 src/lib.rs   | 28 +++-------------------------
 4 files changed, 45 insertions(+), 33 deletions(-)
 create mode 100644 build.rs

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6cf1d6ce..2c755adb 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -22,6 +22,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 - Replace UB code by a legitimate pointer access [#480]
 - Fix flash error flag clearing [#489]
 - Clarify README for windows users [#496]
+- Check "device selected" in `build.rs`
 
 ### Added
 
diff --git a/Cargo.toml b/Cargo.toml
index 9853f4f1..aee47715 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -61,15 +61,12 @@ usb-device = "0.2.8"
 usbd-serial = "0.1.1"
 
 [features]
-device-selected = []
 doc = []
-# deprecated feature
-rt = []
-stm32f100 = ["stm32f1/stm32f100", "device-selected"]
-stm32f101 = ["stm32f1/stm32f101", "device-selected"]
-stm32f103 = ["stm32f1/stm32f103", "device-selected", "has-can", "stm32-usbd"]
-stm32f105 = ["stm32f1/stm32f107", "device-selected", "connectivity"]
-stm32f107 = ["stm32f1/stm32f107", "device-selected", "connectivity"]
+stm32f100 = ["stm32f1/stm32f100"]
+stm32f101 = ["stm32f1/stm32f101"]
+stm32f103 = ["stm32f1/stm32f103", "has-can", "stm32-usbd"]
+stm32f105 = ["stm32f1/stm32f107", "connectivity"]
+stm32f107 = ["stm32f1/stm32f107", "connectivity"]
 
 # Devices with 64 or 128 Kb ROM
 medium = []
diff --git a/build.rs b/build.rs
new file mode 100644
index 00000000..f111aa0b
--- /dev/null
+++ b/build.rs
@@ -0,0 +1,36 @@
+use std::env;
+
+#[derive(Clone, Copy, Debug)]
+enum GetOneError {
+    None,
+    Multiple,
+}
+
+trait IteratorExt: Iterator {
+    fn get_one(self) -> Result<Self::Item, GetOneError>;
+}
+
+impl<T: Iterator> IteratorExt for T {
+    fn get_one(mut self) -> Result<Self::Item, GetOneError> {
+        match (self.next(), self.next()) {
+            (Some(res), None) => Ok(res),
+            (None, _) => Err(GetOneError::None),
+            _ => Err(GetOneError::Multiple),
+        }
+    }
+}
+
+fn main() {
+    let _chip_name = match env::vars()
+        .map(|(a, _)| a)
+        .filter(|x| x.starts_with("CARGO_FEATURE_STM32F1"))
+        .get_one()
+    {
+        Ok(x) => x,
+        Err(GetOneError::None) => panic!("No stm32xx Cargo feature enabled"),
+        Err(GetOneError::Multiple) => panic!("Multiple stm32xx Cargo features enabled"),
+    }
+    .strip_prefix("CARGO_FEATURE_")
+    .unwrap()
+    .to_ascii_lowercase();
+}
diff --git a/src/lib.rs b/src/lib.rs
index 9b88c853..a81f62b8 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -113,9 +113,7 @@ compile_error!(
     "Multiple targets specified. Only a single `--features <target-name>` can be specified."
 );
 
-#[cfg(feature = "device-selected")]
 pub use embedded_hal as hal;
-#[cfg(feature = "device-selected")]
 pub use embedded_hal_02 as hal_02;
 
 #[cfg(feature = "stm32f100")]
@@ -130,52 +128,32 @@ pub use stm32f1::stm32f103 as pac;
 #[cfg(any(feature = "stm32f105", feature = "stm32f107"))]
 pub use stm32f1::stm32f107 as pac;
 
-#[cfg(feature = "device-selected")]
 pub mod adc;
-#[cfg(feature = "device-selected")]
 pub mod afio;
-#[cfg(feature = "device-selected")]
 pub mod backup_domain;
-#[cfg(feature = "device-selected")]
 pub mod bb;
-#[cfg(all(feature = "device-selected", feature = "has-can"))]
+#[cfg(feature = "has-can")]
 pub mod can;
-#[cfg(feature = "device-selected")]
 pub mod crc;
-#[cfg(all(feature = "device-selected", feature = "has-dac"))]
+#[cfg(feature = "has-dac")]
 pub mod dac;
-#[cfg(feature = "device-selected")]
 pub mod dma;
-#[cfg(feature = "device-selected")]
 pub mod flash;
-#[cfg(feature = "device-selected")]
 pub mod gpio;
-#[cfg(feature = "device-selected")]
 pub mod i2c;
-#[cfg(feature = "device-selected")]
 pub mod prelude;
-#[cfg(feature = "device-selected")]
 pub mod qei;
-#[cfg(feature = "device-selected")]
 pub mod rcc;
-#[cfg(feature = "device-selected")]
 pub mod rtc;
-#[cfg(feature = "device-selected")]
 pub mod serial;
-#[cfg(feature = "device-selected")]
 pub mod spi;
-#[cfg(feature = "device-selected")]
 pub mod time;
-#[cfg(feature = "device-selected")]
 pub mod timer;
-#[cfg(all(feature = "device-selected", feature = "stm32-usbd"))]
+#[cfg(feature = "stm32-usbd")]
 pub mod usb;
-#[cfg(feature = "device-selected")]
 pub mod watchdog;
 
-#[cfg(feature = "device-selected")]
 mod sealed {
     pub trait Sealed {}
 }
-#[cfg(feature = "device-selected")]
 use sealed::Sealed;