feat: only generate new version if source files are changed

Author: filipton

Cargo.lock

@@ -63,4 +63,5 @@ opt-level = 3
 overflow-checks = false
 
 [build-dependencies]
+crc32fast = "1.4.2"
 dotenvy = "0.15.7"

Cargo.toml

@@ -1,4 +1,7 @@
-use std::path::Path;
+use std::{
+    hash::Hasher,
+    path::{Path, PathBuf},
+};
 
 const VERSION_TEMPLATE: &'static str = r#"
 pub const VERSION: &'static str = "{version}";
@@ -16,15 +19,34 @@ fn main() {
 
     println!("cargo:rustc-link-arg-bins=-Tlinkall.x");
 
-    let version_str = if let Ok(rel) = std::env::var("RELEASE_BUILD") {
+    let mut hasher = crc32fast::Hasher::new();
+    crc_walkdir(PathBuf::from("src"), &mut hasher);
+    let src_crc = hasher.finalize();
+
+    let mut version_str = if let Ok(rel) = std::env::var("RELEASE_BUILD") {
         rel
     } else {
         let epoch = std::time::SystemTime::now()
             .duration_since(std::time::UNIX_EPOCH)
             .unwrap()
             .as_secs();
 
-        format!("D{epoch}")
+        if let Ok(crc_string) = std::fs::read_to_string(std::env::temp_dir().join("fkm-build-crc"))
+        {
+            let split = crc_string.split_once('|');
+            if let Some((crc_str, ver)) = split {
+                let crc: u32 = crc_str.parse().unwrap_or(0);
+                if crc == src_crc {
+                    ver.to_string()
+                } else {
+                    format!("D{epoch}")
+                }
+            } else {
+                format!("D{epoch}")
+            }
+        } else {
+            format!("D{epoch}")
+        }
     };
 
     let chip = if cfg!(feature = "esp32") {
@@ -41,4 +63,22 @@ fn main() {
         .replace("{firmware}", "STATION");
 
     std::fs::write(Path::new("src").join("version.rs"), gen.trim()).unwrap();
+    _ = std::fs::write(
+        std::env::temp_dir().join("fkm-build-crc"),
+        format!("{src_crc}|{version_str}"),
+    );
+}
+
+fn crc_walkdir(path: PathBuf, hasher: &mut crc32fast::Hasher) {
+    if let Ok(mut dir) = path.read_dir() {
+        while let Some(Ok(entry)) = dir.next() {
+            let file_type = entry.file_type().unwrap();
+            if file_type.is_dir() {
+                crc_walkdir(entry.path(), hasher);
+            } else if file_type.is_file() && entry.file_name().to_string_lossy() != "version.rs" {
+                let string = std::fs::read_to_string(entry.path()).unwrap();
+                hasher.write(string.as_bytes());
+            }
+        }
+    }
 }

build.rs

@@ -0,0 +1,3 @@
+#!/bin/bash
+source ~/export-esp.sh
+cargo build --no-default-features --features=esp32c3 --target=riscv32imc-unknown-none-elf -r && espflash save-image --chip esp32c3 ./target/riscv32imc-unknown-none-elf/release/fkm-firmware "/tmp/fkm-build/esp32c3_STATION_$(cat ./src/version.rs | grep VERSION | cut -d'"' -f 2).bin"