musikr: clean up buildscript

musikr/src/main/jni/build.rs

@@ -1,25 +1,22 @@
 use cxx_build;
 use std::env;
-use std::path::Path;
+use std::path::{Path, PathBuf};
 use std::process::Command;
+use std::error::Error;
 
-fn main() {
-    let working_dir = env::current_dir().expect("Failed to get current working directory");
-    let target = env::var("TARGET").expect("TARGET env var not set");
-    let working_dir = Path::new(&working_dir);
-
-    // Define directories
+fn build_taglib(target: &str, working_dir: &Path) -> Result<PathBuf, Box<dyn Error>> {
     let taglib_src_dir = working_dir.join("taglib");
     let taglib_build_dir = taglib_src_dir.join("build");
     let taglib_pkg_dir = taglib_src_dir.join("pkg");
-
-    // Determine if building for Android
-    let is_android = target.contains("android");
-
     let arch_build_dir = taglib_build_dir.join(&target);
     let arch_pkg_dir = taglib_pkg_dir.join(&target);
 
-    // Prepare cmake command
+    // If lib/libtag.a exists, we don't need to build it
+    if arch_pkg_dir.join("lib/libtag.a").exists() {
+        return Ok(arch_pkg_dir);
+    }
+
+    // Prepare basic cmake arguments
     let mut cmake_args = vec![
         "-B".to_string(),
         arch_build_dir.to_str().unwrap().to_string(),
@@ -33,9 +30,8 @@ fn main() {
         "-DCMAKE_CXX_FLAGS=-fPIC".to_string(),
     ];
 
-    // Add Android-specific arguments if building for Android
-    if is_android {
-        // Get architecture
+    if target.contains("android") {
+        // Android target, we need to tack on the NDK toolchain file/args
         let arch = if target == "x86_64-linux-android" {
             "x86_64"
         } else if target.contains("i686-linux-android") {
@@ -45,7 +41,8 @@ fn main() {
         } else if target.contains("armv7-linux-androideabi") {
             "armeabi-v7a"
         } else {
-            panic!("Unsupported Android target: {}", target);
+            // should never happen
+            return Err(format!("Unsupported Android target: {}", target).into());
         };
 
         let clang_path = env::var("CLANG_PATH").expect("CLANG_PATH env var not set");
@@ -53,7 +50,7 @@ fn main() {
         let ndk_path = if let Some(pos) = clang_path.find(toolchains_marker) {
             &clang_path[..pos]
         } else {
-            panic!("CLANG_PATH does not contain '{}'", toolchains_marker);
+            return Err(format!("CLANG_PATH does not contain '{}'", toolchains_marker).into());
         };
 
         let ndk_toolchain = working_dir.join("android.toolchain.cmake");
@@ -69,10 +66,9 @@ fn main() {
     let status = Command::new("cmake")
         .args(&cmake_args)
         .current_dir(&taglib_src_dir)
-        .status()
-        .expect("Failed to run cmake configure");
+        .status()?;
     if !status.success() {
-        panic!("cmake configure failed for target {}", target);
+        return Err(format!("cmake configure failed for target {}", target).into());
     }
 
     // Build step
@@ -85,10 +81,9 @@ fn main() {
             "-j{}",
             std::thread::available_parallelism().unwrap().get()
         ))
-        .status()
-        .expect("Failed to run cmake build");
+        .status()?;
     if !status.success() {
-        panic!("cmake build failed for target {}", target);
+        return Err(format!("cmake build failed for target {}", target).into());
     }
 
     // Install step
@@ -100,22 +95,15 @@ fn main() {
         .arg("--prefix")
         .arg(arch_pkg_dir.to_str().unwrap())
         .arg("--strip")
-        .status()
-        .expect("Failed to run cmake install");
+        .status()?;
     if !status.success() {
-        panic!("cmake install failed for arch {}", target);
+        return Err(format!("cmake install failed for arch {}", target).into());
     }
 
-    println!(
-        "cargo:rustc-link-search=native={}/lib",
-        arch_pkg_dir.display()
-    );
-    println!("cargo:rustc-link-lib=static=tag");
-    println!("cargo:rustc-link-lib=static=c++_static");
-    println!("cargo:rustc-link-lib=static=c++abi");
-    println!("cargo:rustc-link-lib=unwind");
+    Ok(arch_pkg_dir)
+}
 
-    // Build the shim and cxx bridge together
+fn configure_cxx_bridge(target: &str) -> Result<(), Box<dyn Error>> {
     let mut builder = cxx_build::bridge("src/taglib/bridge.rs");
     builder
         .file("shim/iostream_shim.cpp")
@@ -127,19 +115,44 @@ fn main() {
         .file("shim/id3v2_shim.cpp")
         .file("shim/mp4_shim.cpp")
         .include(format!("taglib/pkg/{}/include", target))
-        .include(".") // Add the current directory to include path
+        .include(".")
         .flag_if_supported("-std=c++14");
 
-    if is_android {
+    if target.contains("android") {
         builder
             .cpp_link_stdlib("c++_static")
-            .flag("-static-libstdc++")
+            // Magic linker flags that statically link exception handling symbols
+            // to the library.
             .flag("-fexceptions")
-            .flag("-funwind-tables"); // Use shared C++ runtime for Android compatibility
+            .flag("-funwind-tables");
     }
     builder.compile("taglib_cxx_bindings");
 
-    // Rebuild if shim files change
-    println!("cargo:rerun-if-changed=shim/");
-    println!("cargo:rerun-if-changed=taglib/");
+    Ok(())
+}
+
+fn main() -> Result<(), Box<dyn Error>> {
+    let working_dir = env::current_dir()?;
+    let target = env::var("TARGET")?;
+    let working_dir = Path::new(&working_dir);
+
+    let arch_pkg_dir = build_taglib(&target, &working_dir)?;
+    println!(
+        "cargo:rustc-link-search=native={}/lib",
+        arch_pkg_dir.display()
+    );
+    println!("cargo:rustc-link-lib=static=tag");
+    println!("cargo:rerun-if-changed=taglib/");
+
+    configure_cxx_bridge(&target)?;
+    if target.contains("android") {
+        // Magic linker flags that statically link the C++ runtime
+        // and exception handling to the library.
+        println!("cargo:rustc-link-lib=static=c++_static");
+        println!("cargo:rustc-link-lib=static=c++abi");
+        println!("cargo:rustc-link-lib=unwind");
+    }
+    println!("cargo:rerun-if-changed=shim/");
+
+    Ok(())
 }