refactor(gen_features): use Rust instead of Python

Done for /embassy-stm32 only
The new generator is in /stm32-gen-features
/stm32-metapac could/should be added too
A CI check "generated features up to date" could/should be performed

2 files changed, 195 insertions, 0 deletions

diff --git a/stm32-gen-features/src/lib.rs b/stm32-gen-features/src/lib.rs
new file mode 100644
index 000000000..b20a1ba4a
--- /dev/null
+++ b/stm32-gen-features/src/lib.rs
@@ -0,0 +1,177 @@
+use std::{
+    collections::HashMap,
+    path::{Path, PathBuf},
+};
+
+const SUPPORTED_FAMILIES: [&str; 8] = [
+    "STM32F0",
+    "STM32F4",
+    "STM32G0",
+    "STM32L0",
+    "STM32L4",
+    "STM32H7",
+    "STM32WB55",
+    "STM32WL55",
+];
+
+const SEPARATOR_START: &str = "# BEGIN GENERATED FEATURES\n";
+const SEPARATOR_END: &str = "# END GENERATED FEATURES\n";
+const HELP: &str = "# Generated by stm32-gen-features. DO NOT EDIT.\n";
+
+/// True if the chip named `name` is supported else false
+fn is_supported(name: &str) -> bool {
+    SUPPORTED_FAMILIES
+        .iter()
+        .any(|family| name.starts_with(family))
+}
+
+/// Get the yaml file names and the associated chip names for supported chips
+///
+/// Print errors to `stderr` when something is returned by the glob but is not in the returned
+/// [`Vec`]
+fn supported_chip_yaml_files_with_names() -> Vec<(PathBuf, String)> {
+    glob::glob("../stm32-data/data/chips/*.yaml")
+        .expect("bad glob pattern")
+        .filter_map(|entry| entry.map_err(|e| eprintln!("{:?}", e)).ok())
+        .filter_map(|entry| {
+            if let Some(name) = entry.file_stem().and_then(|stem| stem.to_str()) {
+                if is_supported(name) {
+                    let owned_name = name.to_lowercase();
+                    Some((entry, owned_name))
+                } else {
+                    eprintln!("{} is not supported", name);
+                    None
+                }
+            } else {
+                eprintln!("{:?} is not a regural file", entry);
+                None
+            }
+        })
+        .collect()
+}
+
+/// Get the list of the cores of a chip by its associated file
+///
+/// # Panic
+/// Panics if the file does not exist or if it contains yaml syntax errors
+///
+/// # None
+/// Returns none if "cores" is not an array
+fn chip_cores(path: &Path) -> Option<Vec<yaml_rust::Yaml>> {
+    let file_contents = std::fs::read_to_string(path).unwrap();
+    let doc = &yaml_rust::YamlLoader::load_from_str(&file_contents).unwrap()[0];
+    doc["cores"].as_vec().cloned()
+}
+
+/// Load the list of chips
+///
+/// # Panic
+/// Panics if a file contains yaml syntax errors or if a value does not have a consistent type
+pub fn load_chip_list() -> HashMap<String, Vec<String>> {
+    let mut result = HashMap::new();
+    for (path, name) in supported_chip_yaml_files_with_names() {
+        let cores = chip_cores(&path).unwrap_or_else(|| panic!("{}[cores] is not an array", name));
+        if cores.len() > 1 {
+            for (i, core) in cores.into_iter().enumerate() {
+                let core_name = core["name"]
+                    .as_str()
+                    .unwrap_or_else(|| panic!("{}[cores][{}][name] is not a string", name, i));
+                let key = format!("{}_{}", name, core_name);
+                let value = vec![format!("stm32-metapac/{}_{}", name, core_name)];
+                result.insert(key, value);
+            }
+        } else {
+            let value = vec![format!("stm32-metapac/{}", &name)];
+            result.insert(name, value);
+        }
+    }
+    result
+}
+
+/// Get contents before and after generated contents
+///
+/// # Panic
+/// Panics when a separator cound not be not found
+fn split_cargo_toml_contents(contents: &str) -> (&str, &str) {
+    let (before, remainder) = contents
+        .split_once(SEPARATOR_START)
+        .unwrap_or_else(|| panic!("missing \"{}\" tag", SEPARATOR_START));
+    let (_, after) = remainder
+        .split_once(SEPARATOR_END)
+        .unwrap_or_else(|| panic!("missing \"{}\" tag", SEPARATOR_END));
+
+    (before, after)
+}
+
+/// Generates new contents for Cargo.toml
+///
+/// # Panic
+/// Panics when a separator cound not be not found
+pub fn generate_cargo_toml_file(
+    previous_text: &str,
+    new_contents: &HashMap<String, Vec<String>>,
+) -> String {
+    let (before, after) = split_cargo_toml_contents(previous_text);
+    let generated_content = toml::to_string(new_contents).unwrap();
+    before.to_owned() + SEPARATOR_START + HELP + &generated_content + SEPARATOR_END + after
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn stm32f407vg_is_supported() {
+        assert!(is_supported("STM32F407VG"))
+    }
+
+    #[test]
+    fn abcdef_is_not_supported() {
+        assert!(!is_supported("ABCDEF"))
+    }
+
+    #[test]
+    fn stm32f407vg_yaml_file_exists() {
+        assert!(supported_chip_yaml_files_with_names()
+            .into_iter()
+            .any(|(path, name)| {
+                name == "stm32f407vg"
+                    && path.to_str() == Some("../stm32-data/data/chips/STM32F407VG.yaml")
+            }))
+    }
+
+    #[test]
+    fn keeps_text_around_separators() {
+        let initial = "\
+before
+# BEGIN GENERATED FEATURES
+# END GENERATED FEATURES
+after
+";
+
+        let expected = "\
+before
+# BEGIN GENERATED FEATURES
+# Generated by stm32-gen-features. DO NOT EDIT.
+a = [\"b\"]
+# END GENERATED FEATURES
+after
+";
+
+        let map = HashMap::from([(String::from("a"), vec![String::from("b")])]);
+        assert_eq!(generate_cargo_toml_file(initial, &map), expected);
+    }
+
+    #[test]
+    #[should_panic]
+    fn does_not_generate_if_separators_are_missing() {
+        let initial = "\
+before
+# END GENERATED FEATURES
+after
+";
+
+        let map = HashMap::from([(String::from("a"), vec![String::from("b")])]);
+        generate_cargo_toml_file(initial, &map);
+    }
+}
diff --git a/stm32-gen-features/src/main.rs b/stm32-gen-features/src/main.rs
new file mode 100644
index 000000000..9f1d8ef34
--- /dev/null
+++ b/stm32-gen-features/src/main.rs
@@ -0,0 +1,18 @@
+use std::collections::HashMap;
+
+use gen_features::{generate_cargo_toml_file, load_chip_list};
+
+fn main() {
+    let chip_list = load_chip_list();
+    update_cargo_file("../embassy-stm32/Cargo.toml", &chip_list);
+}
+
+/// Update a Cargo.toml file
+///
+/// Update the content between "# BEGIN GENERATED FEATURES" and "# END GENERATED FEATURES"
+/// with the given content
+fn update_cargo_file(path: &str, new_contents: &HashMap<String, Vec<String>>) {
+    let previous_text = std::fs::read_to_string(path).unwrap();
+    let new_text = generate_cargo_toml_file(&previous_text, new_contents);
+    std::fs::write(path, new_text).unwrap();
+}