Add intermediate step between SymbolLookup.libraryLookup and System.loadLibrary, that attempts to find library bundle inside jtreesitter jar file

Author: victorgveloso

src/main/java/io/github/treesitter/jtreesitter/internal/ChainedLibraryLookup.java

@@ -1,9 +1,16 @@
 package io.github.treesitter.jtreesitter.internal;
 
 import io.github.treesitter.jtreesitter.NativeLibraryLookup;
+
+import java.io.IOException;
+import java.io.InputStream;
 import java.lang.foreign.Arena;
 import java.lang.foreign.Linker;
 import java.lang.foreign.SymbolLookup;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.StandardCopyOption;
+import java.util.Locale;
 import java.util.Optional;
 import java.util.ServiceLoader;
 
@@ -31,12 +38,120 @@ private static SymbolLookup findLibrary(Arena arena) {
             return SymbolLookup.libraryLookup(library, arena);
         } catch (IllegalArgumentException ex1) {
             try {
-                System.loadLibrary("tree-sitter");
-                return SymbolLookup.loaderLookup();
+                findLibraryBundledInJar("tree-sitter");
             } catch (UnsatisfiedLinkError ex2) {
-                ex1.addSuppressed(ex2);
-                throw ex1;
+                try {
+                    System.loadLibrary("tree-sitter");
+                } catch (UnsatisfiedLinkError ex3) {
+                    ex2.addSuppressed(ex3);
+                    ex1.addSuppressed(ex2);
+                    throw ex1;
+                }
+            }
+            return SymbolLookup.loaderLookup();
+        }
+    }
+
+    private static void findLibraryBundledInJar(String libBaseName) throws UnsatisfiedLinkError {
+        /*
+         * Strategy:
+         * 1) Resolve os & arch and compute candidate resource names
+         * 2) Try to locate resource inside JAR with several common layouts
+         * 3) Extract to temp file and System.load it
+         */
+
+        final String mappedName = System.mapLibraryName(libBaseName); // platform-native file name (libtree-sitter.so, tree-sitter.dll, ...)
+        final String os = detectOs();
+        final String arch = detectArch();
+        final String ext = extractExtension(mappedName); // ".so" or ".dll" or ".dylib"
+
+        // Candidate resource paths inside the JAR. Adapt these to however you pack native libs.
+        String[] candidates = new String[] {
+            // platform-specific directories (most specific)
+            "/natives/" + os + "-" + arch + "/" + mappedName,
+            "/natives/" + arch + "/" + mappedName,
+            "/native/" + os + "-" + arch + "/" + mappedName,
+            "/native/" + arch + "/" + mappedName,
+            // less specific
+            "/natives/" + mappedName,
+            "/native/" + mappedName,
+            // fallback: just the file at root of jar (not recommended but sometimes used)
+            "/" + mappedName
+        };
+
+        InputStream foundStream = null;
+        String foundResource = null;
+        for (String candidate : candidates) {
+            InputStream is = ChainedLibraryLookup.class.getResourceAsStream(candidate);
+            if (is != null) {
+                foundStream = is;
+                foundResource = candidate;
+                break;
+            }
+        }
+
+        if (foundStream == null) {
+            // helpful message mentioning what we tried
+            String tried = String.join(", ", candidates);
+            throw new UnsatisfiedLinkError("Could not find bundled native library resource for '"
+                + libBaseName + "'. Tried: " + tried);
+        }
+
+        // Create temp file and copy resource contents
+        Path temp = null;
+        try (InputStream in = foundStream) {
+            String suffix = ext != null ? ext : null; // Files.createTempFile needs suffix with dot
+            // create a predictable prefix but allow uniqueness
+            String prefix = "jtreesitter-" + libBaseName + "-";
+            if (suffix == null) {
+                // fallback if we couldn't detect extension
+                temp = Files.createTempFile(prefix, null);
+            } else {
+                temp = Files.createTempFile(prefix, suffix);
+            }
+            // Ensure cleanup on exit as best-effort
+            temp.toFile().deleteOnExit();
+
+            // Copy bytes
+            Files.copy(in, temp, StandardCopyOption.REPLACE_EXISTING);
+
+            // On unix-like systems make executable (not strictly necessary for shared objects, but safe)
+            try {
+                temp.toFile().setExecutable(true, true);
+            } catch (Exception ignored) {
             }
+
+            // Load the native library from the extracted temp file
+            System.load(temp.toAbsolutePath().toString());
+        } catch (IOException e) {
+            // wrap as UnsatisfiedLinkError to match calling code expectations
+            UnsatisfiedLinkError ule = new UnsatisfiedLinkError("Failed to extract and load native library from JAR (resource: " + foundResource + "): " + e);
+            ule.initCause(e);
+            throw ule;
         }
     }
+
+    private static String detectOs() {
+        String osProp = System.getProperty("os.name", "generic").toLowerCase(Locale.ENGLISH);
+        if (osProp.contains("win")) return "windows";
+        if (osProp.contains("mac") || osProp.contains("darwin") || osProp.contains("os x")) return "macos";
+        if (osProp.contains("nux") || osProp.contains("nix") || osProp.contains("linux")) return "linux";
+        // fallback
+        return osProp.replaceAll("\\s+", "");
+    }
+
+    private static String detectArch() {
+        String archProp = System.getProperty("os.arch", "").toLowerCase(Locale.ENGLISH);
+        if (archProp.equals("x86_64") || archProp.equals("amd64")) return "x86_64";
+        if (archProp.equals("aarch64") || archProp.equals("arm64")) return "aarch64";
+        // other architectures we return raw (but normalized)
+        return archProp.replaceAll("\\s+", "");
+    }
+
+    private static String extractExtension(String mappedName) {
+        if (mappedName == null) return null;
+        int idx = mappedName.lastIndexOf('.');
+        if (idx == -1) return null;
+        return mappedName.substring(idx); // includes dot, e.g. ".so"
+    }
 }