fix and refactor: rust port not finding metacall shared libraries and config files

source/ports/rs_port/build.rs

@@ -1,38 +1,199 @@
-use std::env;
+use std::{
+    env, fs,
+    path::{Path, PathBuf},
+    vec,
+};
+
+// Search for MetaCall libraries in platform-specific locations
+// Handle custom installation paths via environment variables
+// Find configuration files recursively
+// Provide helpful error messages when things aren't found
+
+/// Represents the install paths for a platform
+struct InstallPath {
+    paths: Vec<PathBuf>,
+    name: String,
+}
+
+/// Find files recursively in a directory matching a pattern
+fn find_files_recursively<P: AsRef<Path>>(
+    root_dir: P,
+    filename: &str,
+    max_depth: Option<usize>,
+) -> Result<Vec<PathBuf>, Box<dyn std::error::Error>> {
+    let mut matches = Vec::new();
+    let mut stack = vec![(root_dir.as_ref().to_path_buf(), 0)];
+
+    while let Some((current_dir, depth)) = stack.pop() {
+        if let Some(max) = max_depth {
+            if depth > max {
+                continue;
+            }
+        }
+
+        if let Ok(entries) = fs::read_dir(&current_dir) {
+            for entry in entries.flatten() {
+                let path = entry.path();
+
+                if path.is_file() {
+                    // Simple filename comparison instead of regex
+                    if let Some(file_name) = path.file_name().and_then(|n| n.to_str()) {
+                        if file_name == filename {
+                            matches.push(path);
+                        }
+                    }
+                } else if path.is_dir() {
+                    stack.push((path, depth + 1));
+                }
+            }
+        }
+    }
+
+    Ok(matches)
+}
+
+fn platform_install_paths() -> Result<InstallPath, Box<dyn std::error::Error>> {
+    // let platform = env::var("PLATFORM");
+
+    if cfg!(target_os = "windows") {
+        // defaults to path:
+        // C:\Users\Default\AppData\Local
+        let local_app_data = env::var("LOCALAPPDATA")
+            .unwrap_or_else(|_| String::from("C:\\Users\\Default\\AppData\\Local"));
+
+        println!("windows");
+        Ok(InstallPath {
+            paths: vec![PathBuf::from(local_app_data)
+                .join("Metacall")
+                .join("metacall")],
+            name: "metacall.dll".to_string(),
+        })
+    } else if cfg!(target_os = "macos") {
+        println!("macos");
+        Ok(InstallPath {
+            paths: vec![
+                PathBuf::from("/opt/homebrew/lib/"),
+                PathBuf::from("/usr/local/lib/"),
+            ],
+            name: "metacall.dylib".to_string(),
+        })
+    } else if cfg!(target_os = "linux") {
+        println!("linux");
+        Ok(InstallPath {
+            paths: vec![PathBuf::from("/usr/local/lib/"), PathBuf::from("/gnu/lib/")],
+            name: "libmetacall.so".to_string(),
+        })
+    } else {
+        Err(format!("Platform {} not supported", env::consts::OS).into())
+    }
+}
+
+/// Get search paths, checking for custom installation path first
+fn get_search_config() -> Result<InstallPath, Box<dyn std::error::Error>> {
+    // First, check if user specified a custom path
+    if let Ok(custom_path) = env::var("METACALL_INSTALL_PATH") {
+        // For custom paths, we need to search for any metacall library variant
+        return Ok(InstallPath {
+            paths: vec![PathBuf::from(custom_path)],
+            name: r"^(lib)?metacall(d)?\.(so|dylib|dll)$".to_string(),
+        });
+    }
+
+    // Fall back to platform-specific paths
+    platform_install_paths()
+}
+
+/// Find the MetaCall library
+/// This orchestrates the search process
+fn find_metacall_library() -> Result<PathBuf, Box<dyn std::error::Error>> {
+    let search_config = get_search_config()?;
+
+    // Search in each configured path
+    for search_path in &search_config.paths {
+        println!(
+            "cargo:warning=Searching for MetaCall in: {}",
+            search_path.display()
+        );
+
+        // Only search at depth 0 (current directory)
+        match find_files_recursively(search_path, &search_config.name, Some(0)) {
+            Ok(files) if !files.is_empty() => {
+                let found_lib = &files[0];
+                println!(
+                    "cargo:warning=Found MetaCall library: {}",
+                    found_lib.display()
+                );
+                return Ok(found_lib.clone());
+            }
+            Ok(_) => {
+                // No files found in this path, continue searching
+                continue;
+            }
+            Err(e) => {
+                println!(
+                    "cargo:warning=Error searching in {}: {}",
+                    search_path.display(),
+                    e
+                );
+                continue;
+            }
+        }
+    }
+
+    // If we get here, library wasn't found
+    let search_paths: Vec<String> = search_config
+        .paths
+        .iter()
+        .map(|p| p.display().to_string())
+        .collect();
+
+    Err(format!(
+        "MetaCall library not found. Searched in: {}. \
+        If you have it installed elsewhere, set METACALL_INSTALL_PATH environment variable.",
+        search_paths.join(", ")
+    )
+    .into())
+}
 
 fn main() {
     // When running tests from CMake
     if let Ok(val) = env::var("PROJECT_OUTPUT_DIR") {
-        // Link search path to build folder
         println!("cargo:rustc-link-search=native={val}");
 
-        // Link against correct version of metacall
         match env::var("CMAKE_BUILD_TYPE") {
-            Ok(val) => {
-                if val == "Debug" {
-                    // Try to link the debug version when running tests
-                    println!("cargo:rustc-link-lib=dylib=metacalld");
-                } else {
-                    println!("cargo:rustc-link-lib=dylib=metacall");
-                }
+            Ok(val) if val == "Debug" => {
+                println!("cargo:rustc-link-lib=dylib=metacalld");
             }
-            Err(_) => {
+            _ => {
                 println!("cargo:rustc-link-lib=dylib=metacall");
             }
         }
-    } else {
-        // When building from Cargo
-        let profile = env::var("PROFILE").unwrap();
-        match profile.as_str() {
-            // "debug" => {
-            //     println!("cargo:rustc-link-lib=dylib=metacalld");
-            // }
-            "debug" | "release" => {
-                println!("cargo:rustc-link-lib=dylib=metacall")
+        return;
+    }
+
+    // When building from Cargo - try to find MetaCall
+    match find_metacall_library() {
+        Ok(lib_path) => {
+            // Extract the directory containing the library
+            if let Some(lib_dir) = lib_path.parent() {
+                println!("cargo:rustc-link-search=native={}", lib_dir.display());
             }
-            _ => {
-                println!("cargo:rustc-link-lib=dylib=metacall")
+
+            // Link against the library
+            let profile = env::var("PROFILE").unwrap_or_else(|_| "release".to_string());
+            match profile.as_str() {
+                "debug" | "release" => {
+                    println!("cargo:rustc-link-lib=dylib=metacall");
+                }
+                _ => {
+                    println!("cargo:rustc-link-lib=dylib=metacall");
+                }
             }
         }
+        Err(e) => {
+            println!("cargo:warning={e}");
+            // Still try to link in case the library is in system paths
+            println!("cargo:rustc-link-lib=dylib=metacall");
+        }
     }
 }