Share downloaded bitcoind path with build script

build.rs

@@ -22,6 +22,9 @@ mod download {
     use tar::Archive;
 
     include!("src/versions.rs");
+    mod download_path {
+        include!("src/download_path.rs");
+    }
 
     #[cfg(all(
         target_os = "macos",
@@ -83,10 +86,7 @@ mod download {
             std::fs::create_dir(&bitcoin_exe_home)
                 .with_context(|| format!("cannot create dir {:?}", bitcoin_exe_home))?;
         }
-        let existing_filename = bitcoin_exe_home
-            .join(format!("bitcoin-{}", VERSION))
-            .join("bin")
-            .join("bitcoind");
+        let existing_filename = download_path::downloaded_exe_path(Path::new(&out_dir), VERSION);
 
         if !existing_filename.exists() {
             println!(

src/download_path.rs

@@ -0,0 +1,40 @@
+use std::path::{Path, PathBuf};
+
+pub(crate) fn downloaded_exe_path(out_dir: impl AsRef<Path>, version: &str) -> PathBuf {
+    let mut path = out_dir.as_ref().to_path_buf();
+    path.push("bitcoin");
+    path.push(format!("bitcoin-{}", version));
+    path.push("bin");
+
+    if cfg!(target_os = "windows") {
+        path.push("bitcoind.exe");
+    } else {
+        path.push("bitcoind");
+    }
+
+    path
+}
+
+#[cfg(test)]
+mod tests {
+    use super::downloaded_exe_path;
+    use std::path::Path;
+
+    #[test]
+    fn downloaded_exe_path_uses_bitcoin_layout() {
+        let executable = if cfg!(target_os = "windows") {
+            "bitcoind.exe"
+        } else {
+            "bitcoind"
+        };
+
+        assert_eq!(
+            downloaded_exe_path("/tmp/out", "26.0"),
+            Path::new("/tmp/out")
+                .join("bitcoin")
+                .join("bitcoin-26.0")
+                .join("bin")
+                .join(executable)
+        );
+    }
+}

src/lib.rs

@@ -3,6 +3,9 @@
 
 mod versions;
 
+#[cfg(feature = "download")]
+mod download_path;
+
 use crate::bitcoincore_rpc::jsonrpc::serde_json::Value;
 use anyhow::Context;
 use bitcoincore_rpc::{Auth, Client, RpcApi};
@@ -503,16 +506,7 @@ pub fn downloaded_exe_path() -> anyhow::Result<String> {
         return Err(Error::SkipDownload.into());
     }
 
-    let mut path: PathBuf = env!("OUT_DIR").into();
-    path.push("bitcoin");
-    path.push(format!("bitcoin-{}", versions::VERSION));
-    path.push("bin");
-
-    if cfg!(target_os = "windows") {
-        path.push("bitcoind.exe");
-    } else {
-        path.push("bitcoind");
-    }
+    let path = download_path::downloaded_exe_path(env!("OUT_DIR"), versions::VERSION);
 
     Ok(format!("{}", path.display()))
 }
@@ -521,7 +515,7 @@ pub fn downloaded_exe_path() -> anyhow::Result<String> {
 ///
 /// 1) If it's specified in the `BITCOIND_EXE` env var
 /// 2) If there is no env var but an auto-download feature such as `23_1` is enabled, returns the
-/// path of the downloaded executabled
+///    path of the downloaded executabled
 /// 3) If neither of the precedent are available, the `bitcoind` executable is searched in the `PATH`
 pub fn exe_path() -> anyhow::Result<String> {
     if let Ok(path) = std::env::var("BITCOIND_EXE") {