Set cargo:rerun-if-changed for C files and cargo:rerun-if-env-changed for custom environment variables

Author: schteve

freertos-cargo-build/src/lib.rs

@@ -1,4 +1,5 @@
 use cc::Build;
+use std::ffi::OsStr;
 use std::fmt::Display;
 use std::{fmt, env};
 use std::path::{Path, PathBuf};
@@ -240,26 +241,72 @@ impl Builder {
 
         self.verify_paths()?;
 
-        // FreeRTOS header files
-        b.include(self.freertos_include_dir());
-        // FreeRTOS port header files (e.g. portmacro.h)
-        b.include(self.get_freertos_port_dir());
-        b.include(self.freertos_config_dir.clone());
-        b.file(self.heap_c_file());
-        self.freertos_files().iter().for_each(|f| {
-            b.file(f);
-        });
-        self.freertos_port_files().iter().for_each(|f| {
-            b.file(f);
-        });
-        self.freertos_shim_files().iter().for_each(|f| {
-            b.file(f);
-        });
+        add_include_with_rerun(&mut b, self.freertos_include_dir()); // FreeRTOS header files
+        add_include_with_rerun(&mut b, self.get_freertos_port_dir()); // FreeRTOS port header files (e.g. portmacro.h)
+        add_include_with_rerun(&mut b, &self.freertos_config_dir); // User's FreeRTOSConfig.h
+
+        add_build_files_with_rerun(&mut b, self.freertos_files()); // Non-port C files
+        add_build_files_with_rerun(&mut b, self.freertos_port_files()); // Port C files
+        add_build_files_with_rerun(&mut b, self.freertos_shim_files()); // Shim C file
+        add_build_file_with_rerun(&mut b, self.heap_c_file()); // Heap C file
+
+        println!("cargo:rerun-if-env-changed={ENV_KEY_FREERTOS_SRC}");
+        println!("cargo:rerun-if-env-changed={ENV_KEY_FREERTOS_CONFIG}");
+        println!("cargo:rerun-if-env-changed={ENV_KEY_FREERTOS_SHIM}");
 
         b.try_compile("freertos").map_err(|e| Error::new(&format!("{}", e)))?;
 
         Ok(())
     }
+
+    /// Add a single file to the build. This also tags the file with cargo:rerun-if-changed so that cargo will re-run
+    /// the build script if the file changes. If you don't want this additional behavior, use get_cc().file() to
+    /// directly add a file to the build instead.
+    pub fn add_build_file<P: AsRef<Path>>(&mut self, file: P) {
+        add_build_file_with_rerun(self.get_cc(), file);
+    }
+
+    /// Add multiple files to the build. This also tags the files with cargo:rerun-if-changed so that cargo will re-run
+    /// the build script if the files change. If you don't want this additional behavior, use get_cc().files() to
+    /// directly add files to the build instead.
+    pub fn add_build_files<P>(&mut self, files: P)
+    where
+        P: IntoIterator,
+        P::Item: AsRef<Path>,
+    {
+        add_build_files_with_rerun(self.get_cc(), files);
+    }
+}
+
+fn add_build_file_with_rerun<P: AsRef<Path>>(build: &mut Build, file: P) {
+    build.file(&file);
+    println!("cargo:rerun-if-changed={}", file.as_ref().display());
+}
+
+fn add_build_files_with_rerun<P>(build: &mut Build, files: P)
+where
+    P: IntoIterator,
+    P::Item: AsRef<Path>,
+{
+    for file in files.into_iter() {
+        add_build_file_with_rerun(build, file);
+    }
+}
+
+fn add_include_with_rerun<P: AsRef<Path>>(build: &mut Build, dir: P) {
+    build.include(&dir);
+
+    WalkDir::new(&dir)
+        .follow_links(false)
+        .max_depth(1)
+        .into_iter()
+        .filter_map(|e| e.ok())
+        .for_each(|entry| {
+            let f_name = entry.path();
+            if f_name.extension() == Some(OsStr::new("h")) {
+                println!("cargo:rerun-if-changed={}", f_name.display());
+            }
+        });
 }
 
 #[test]

freertos-rust-examples/build.rs

@@ -20,8 +20,8 @@ fn main() {
         b.freertos_config("examples/win");
         // TODO: in future all FreeRTOS API should be implemented by the freertos-rust crate
         // until then, we need to compile some C code manually
-        b.get_cc().file("examples/win/hooks.c");
-        b.get_cc().file("examples/win/Run-time-stats-utils.c");
+        b.add_build_file("examples/win/hooks.c");
+        b.add_build_file("examples/win/Run-time-stats-utils.c");
 
         if target_env == "msvc" {
             println!("cargo:rustc-link-lib=static=winmm");
@@ -31,8 +31,8 @@ fn main() {
     if target == "x86_64-unknown-linux-gnu" {
         b.freertos_config("examples/linux");
 
-        b.get_cc().file("examples/linux/hooks.c");
-        // b.get_cc().file("examples/linux/Run-time-stats-utils.c"); // Unimplemented yet..
+        b.add_build_file("examples/linux/hooks.c");
+        // b.add_build_file("examples/linux/Run-time-stats-utils.c"); // Unimplemented yet..
     }
 
     if target == "thumbv7m-none-eabi" {