No longer redownloads unicorn each cargo build

bindings/rust/build.rs

@@ -1,11 +1,11 @@
 use bytes::Buf;
 use flate2::read::GzDecoder;
 use reqwest::header::USER_AGENT;
-use std::path::PathBuf;
+use std::path::{Path, PathBuf};
 use std::{env, process::Command};
 use tar::Archive;
 
-fn find_unicorn(unicorn_dir: &PathBuf) -> Option<PathBuf> {
+fn find_unicorn(unicorn_dir: &Path) -> Option<PathBuf> {
     for entry in std::fs::read_dir(unicorn_dir).ok()? {
         let entry = entry.unwrap();
         let path = entry.path();
@@ -18,7 +18,12 @@ fn find_unicorn(unicorn_dir: &PathBuf) -> Option<PathBuf> {
     None
 }
 
-fn download_unicorn() -> Option<String> {
+fn out_dir() -> PathBuf {
+    let out_dir = env::var("OUT_DIR").unwrap();
+    Path::new(&out_dir).to_path_buf()
+}
+
+fn download_unicorn() -> PathBuf {
     // https://docs.github.com/en/rest/reference/repos#download-a-repository-archive-tar
     let pkg_version;
     if let Ok(unicorn_version) = env::var("UNICORN_VERSION") {
@@ -26,7 +31,7 @@ fn download_unicorn() -> Option<String> {
     } else {
         pkg_version = env::var("CARGO_PKG_VERSION").unwrap();
     }
-    let out_dir = PathBuf::from(env::var("OUT_DIR").unwrap());
+    let out_dir = out_dir();
     let client = reqwest::blocking::Client::new();
     let resp = client
         .get(format!(
@@ -43,89 +48,106 @@ fn download_unicorn() -> Option<String> {
     let mut archive = Archive::new(tar);
     archive.unpack(&out_dir).unwrap();
 
-    match find_unicorn(&out_dir) {
+    find_unicorn(&out_dir).unwrap()
-        Some(dir) => Some(String::from(out_dir.join(dir).to_str()?)),
-        None => None,
-    }
 }
 
 fn main() {
     let profile = env::var("PROFILE").unwrap();
 
-    let unicorn_dir;
+    if let Some(unicorn_dir) = find_unicorn(&out_dir()) {
-    if let Result::Ok(_) = env::var("CI") {
+        let rust_build_path = unicorn_dir.join("rust_build");
-        unicorn_dir = format!("../..");
-    } else {
-        unicorn_dir = download_unicorn().unwrap();
-    }
-
-    println!("cargo:rerun-if-changed={}", &unicorn_dir);
-
-    // We don't use TARGET since we can't cross-build.
-    if env::consts::OS == "windows" {
-        // Windows
-        let mut cmd = Command::new("cmake");
-        cmd.current_dir(&unicorn_dir)
-            .arg("-B")
-            .arg("rust_build")
-            .arg("-DUNICORN_BUILD_SHARED=off")
-            .arg("-G")
-            .arg("Visual Studio 16 2019");
-
-        if profile == "debug" {
-            cmd.arg("-DCMAKE_BUILD_TYPE=Debug");
-        } else {
-            cmd.arg("-DCMAKE_BUILD_TYPE=Release");
-        }
-
-        cmd.output()
-            .expect("Fail to create build directory on Windows.");
-
-        let mut platform = "x64";
-        let mut conf = "Release";
-        if std::mem::size_of::<usize>() == 4 {
-            platform = "Win32";
-        }
-        if profile == "debug" {
-            conf = "Debug";
-        }
-
-        Command::new("msbuild")
-            .current_dir(format!("{}/rust_build", &unicorn_dir))
-            .arg("unicorn.sln")
-            .arg("-m")
-            .arg("-p:Platform=".to_owned() + platform)
-            .arg("-p:Configuration=".to_owned() + conf)
-            .output()
-            .expect("Fail to build unicorn on Win32.");
         println!(
-            "cargo:rustc-link-search={}/rust_build/{}",
+            "cargo:rustc-link-search={}",
-            unicorn_dir, conf
+            rust_build_path.to_str().unwrap()
+        );
+        println!(
+            "cargo:rustc-link-search={}",
+            rust_build_path.join("Debug").to_str().unwrap()
+        );
+        println!(
+            "cargo:rustc-link-search={}",
+            rust_build_path.join("Release").to_str().unwrap()
         );
     } else {
-        // Most Unix-like systems
+        let unicorn_dir = if let Result::Ok(_) = env::var("CI") {
-        let mut cmd = Command::new("cmake");
+            Path::new("..").join("..")
-        cmd.current_dir(&unicorn_dir)
-            .arg("-B")
-            .arg("rust_build")
-            .arg("-DUNICORN_BUILD_SHARED=off");
-
-        if profile == "debug" {
-            cmd.arg("-DCMAKE_BUILD_TYPE=Debug");
         } else {
-            cmd.arg("-DCMAKE_BUILD_TYPE=Release");
+            println!("cargo:warning=Unicorn not found. Downloading...");
+            download_unicorn()
+        };
+
+        let rust_build_path = unicorn_dir.join("rust_build");
+
+        let mut cmd = Command::new("cmake");
+
+        // We don't use TARGET since we can't cross-build.
+        if env::consts::OS == "windows" {
+            // Windows
+            cmd.current_dir(&unicorn_dir)
+                .arg("-B")
+                .arg("rust_build")
+                .arg("-DUNICORN_BUILD_SHARED=off")
+                .arg("-G")
+                .arg("Visual Studio 16 2019");
+
+            if profile == "debug" {
+                cmd.arg("-DCMAKE_BUILD_TYPE=Debug");
+            } else {
+                cmd.arg("-DCMAKE_BUILD_TYPE=Release");
+            }
+
+            cmd.output()
+                .expect("Fail to create build directory on Windows.");
+
+            let mut platform = "x64";
+            let mut conf = "Release";
+            if std::mem::size_of::<usize>() == 4 {
+                platform = "Win32";
+            }
+            if profile == "debug" {
+                conf = "Debug";
+            }
+
+            Command::new("msbuild")
+                .current_dir(&rust_build_path)
+                .arg("unicorn.sln")
+                .arg("-m")
+                .arg("-p:Platform=".to_owned() + platform)
+                .arg("-p:Configuration=".to_owned() + conf)
+                .output()
+                .expect("Fail to build unicorn on Win32.");
+            println!(
+                "cargo:rustc-link-search={}",
+                rust_build_path.join(conf).to_str().unwrap()
+            );
+        } else {
+            // Most Unix-like systems
+            let mut cmd = Command::new("cmake");
+            cmd.current_dir(&unicorn_dir)
+                .arg("-B")
+                .arg("rust_build")
+                .arg("-DUNICORN_BUILD_SHARED=off");
+
+            if profile == "debug" {
+                cmd.arg("-DCMAKE_BUILD_TYPE=Debug");
+            } else {
+                cmd.arg("-DCMAKE_BUILD_TYPE=Release");
+            }
+
+            cmd.output()
+                .expect("Fail to create build directory on *nix.");
+
+            Command::new("make")
+                .current_dir(&rust_build_path)
+                .arg("-j6")
+                .output()
+                .expect("Fail to build unicorn on *nix.");
+
+            println!(
+                "cargo:rustc-link-search={}",
+                rust_build_path.to_str().unwrap()
+            );
         }
-
-        cmd.output()
-            .expect("Fail to create build directory on *nix.");
-
-        Command::new("make")
-            .current_dir(format!("{}/rust_build", &unicorn_dir))
-            .arg("-j6")
-            .output()
-            .expect("Fail to build unicorn on *nix.");
-
-        println!("cargo:rustc-link-search={}/rust_build", unicorn_dir);
     }
 
     // This is a workaround for Unicorn static link since libunicorn.a is also linked again lib*-softmmu.a.
@@ -157,4 +179,7 @@ fn main() {
         println!("cargo:rustc-link-lib={}-softmmu", arch);
     }
     println!("cargo:rustc-link-lib=unicorn-common");
+
+    println!("cargo:rerun-if-changed=build.rs");
+    println!("cargo:rerun-if-changed=src");
 }