Add NativeLoader listener support

components/native-loader/src/main/java/datadog/nativeloader/CompositeLibraryLoadingListener.java

@@ -0,0 +1,133 @@
+package datadog.nativeloader;
+
+import java.net.URL;
+import java.nio.file.Path;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+
+final class CompositeLibraryLoadingListener extends SafeLibraryLoadingListener {
+  private final Collection<? extends LibraryLoadingListener> listeners;
+
+  CompositeLibraryLoadingListener(LibraryLoadingListener... listeners) {
+    this(Arrays.asList(listeners));
+  }
+
+  CompositeLibraryLoadingListener(Collection<? extends LibraryLoadingListener> listeners) {
+    this.listeners = listeners;
+  }
+
+  @Override
+  public boolean isNop() {
+    return this.listeners.isEmpty();
+  }
+
+  int size() {
+    return this.listeners.size();
+  }
+
+  @Override
+  public void onResolveDynamic(
+      PlatformSpec platformSpec,
+      String optionalComponent,
+      String libName,
+      boolean isPreloaded,
+      URL optionalUrl) {
+    for (LibraryLoadingListener listener : this.listeners) {
+      try {
+        listener.onResolveDynamic(
+            platformSpec, optionalComponent, libName, isPreloaded, optionalUrl);
+      } catch (Throwable ignored) {
+      }
+    }
+  }
+
+  @Override
+  public void onResolveDynamicFailure(
+      PlatformSpec platformSpec,
+      String optionalComponent,
+      String libName,
+      LibraryLoadException optionalCause) {
+    for (LibraryLoadingListener listener : this.listeners) {
+      try {
+        listener.onResolveDynamicFailure(platformSpec, optionalComponent, libName, optionalCause);
+      } catch (Throwable ignored) {
+      }
+    }
+  }
+
+  @Override
+  public void onLoad(
+      PlatformSpec platformSpec,
+      String optionalComponent,
+      String libName,
+      boolean isPreloaded,
+      Path optionalLibPath) {
+    for (LibraryLoadingListener listener : this.listeners) {
+      try {
+        listener.onLoad(platformSpec, optionalComponent, libName, isPreloaded, optionalLibPath);
+      } catch (Throwable ignored) {
+      }
+    }
+  }
+
+  @Override
+  public void onTempFileCreated(
+      PlatformSpec platformSpec, String optionalComponent, String libName, Path tempFile) {
+    for (LibraryLoadingListener listener : this.listeners) {
+      try {
+        listener.onTempFileCreated(platformSpec, optionalComponent, libName, tempFile);
+      } catch (Throwable ignored) {
+      }
+    }
+  }
+
+  @Override
+  public void onTempFileCreationFailure(
+      PlatformSpec platformSpec,
+      String optionalComponent,
+      String libName,
+      Path tempDir,
+      String libExt,
+      Path optionalTempFile,
+      Throwable optionalCause) {
+    for (LibraryLoadingListener listener : this.listeners) {
+      try {
+        listener.onTempFileCreationFailure(
+            platformSpec,
+            optionalComponent,
+            libName,
+            tempDir,
+            libExt,
+            optionalTempFile,
+            optionalCause);
+      } catch (Throwable ignored) {
+      }
+    }
+  }
+
+  @Override
+  public void onTempFileCleanup(
+      PlatformSpec platformSpec, String optionalComponent, String libName, Path tempPath) {
+    for (LibraryLoadingListener listener : this.listeners) {
+      try {
+        listener.onTempFileCleanup(platformSpec, optionalComponent, libName, tempPath);
+      } catch (Throwable ignored) {
+      }
+    }
+  }
+
+  @Override
+  public CompositeLibraryLoadingListener join(LibraryLoadingListener... listeners) {
+    ArrayList<LibraryLoadingListener> combinedListeners =
+        new ArrayList<>(this.listeners.size() + listeners.length);
+    combinedListeners.addAll(this.listeners);
+    combinedListeners.addAll(Arrays.asList(listeners));
+    return new CompositeLibraryLoadingListener(combinedListeners);
+  }
+
+  @Override
+  public String toString() {
+    return this.getClass().getSimpleName() + ":" + this.listeners.toString();
+  }
+}

components/native-loader/src/main/java/datadog/nativeloader/LibFile.java

@@ -7,75 +7,122 @@
  * Represents a resolved library
  *
  * <ul>
- *   <li>library may be preloaded - with no backing file
- *   <li>regular file - that doesn't require clean-up
- *   <li>temporary file - copying from another source - that does require clean-up
+ *   <li>library may be preloaded - with no backing optionalFile
+ *   <li>regular optionalFile - that doesn't require clean-up
+ *   <li>temporary optionalFile - copying from another source - that does require clean-up
  * </ul>
  */
 public final class LibFile implements AutoCloseable {
   static final boolean NO_CLEAN_UP = false;
   static final boolean CLEAN_UP = true;
 
-  static final LibFile preloaded(String libName) {
-    return new LibFile(libName, null, NO_CLEAN_UP);
+  static final LibFile preloaded(
+      PlatformSpec platformSpec,
+      String optionalComponent,
+      String libName,
+      SafeLibraryLoadingListener listeners) {
+    return new LibFile(platformSpec, optionalComponent, libName, null, NO_CLEAN_UP, listeners);
   }
 
-  static final LibFile fromFile(String libName, File file) {
-    return new LibFile(libName, file, NO_CLEAN_UP);
+  static final LibFile fromFile(
+      PlatformSpec platformSpec,
+      String optionalComponent,
+      String libName,
+      File optionalFile,
+      SafeLibraryLoadingListener listeners) {
+    return new LibFile(
+        platformSpec, optionalComponent, libName, optionalFile, NO_CLEAN_UP, listeners);
   }
 
-  static final LibFile fromTempFile(String libName, File file) {
-    return new LibFile(libName, file, CLEAN_UP);
+  static final LibFile fromTempFile(
+      PlatformSpec platformSpec,
+      String optionalComponent,
+      String libName,
+      File optionalFile,
+      SafeLibraryLoadingListener listeners) {
+    return new LibFile(platformSpec, optionalComponent, libName, optionalFile, CLEAN_UP, listeners);
   }
 
+  final PlatformSpec platformSpec;
+  final String optionalComponent;
   final String libName;
 
-  final File file;
+  final File optionalFile;
   final boolean needsCleanup;
 
-  LibFile(String libName, File file, boolean needsCleanup) {
+  final SafeLibraryLoadingListener listeners;
+
+  LibFile(
+      PlatformSpec platformSpec,
+      String optionalComponent,
+      String libName,
+      File optionalFile,
+      boolean needsCleanup,
+      SafeLibraryLoadingListener listeners) {
+    this.platformSpec = platformSpec;
+    this.optionalComponent = optionalComponent;
     this.libName = libName;
 
-    this.file = file;
+    this.optionalFile = optionalFile;
     this.needsCleanup = needsCleanup;
+
+    this.listeners = listeners;
   }
 
   /** Indicates if this library was "preloaded" */
   public boolean isPreloaded() {
-    return (this.file == null);
+    return (this.optionalFile == null);
   }
 
   /** Loads the underlying library into the JVM */
   public void load() throws LibraryLoadException {
-    if (this.isPreloaded()) return;
+    boolean isPreloaded = this.isPreloaded();
+    if (isPreloaded) {
+      this.listeners.onLoad(
+          this.platformSpec, this.optionalComponent, this.libName, isPreloaded, null);
+      return;
+    }
 
     try {
       Runtime.getRuntime().load(this.getAbsolutePath());
+
+      this.listeners.onLoad(
+          this.platformSpec,
+          this.optionalComponent,
+          this.libName,
+          isPreloaded,
+          this.optionalFile.toPath());
     } catch (Throwable t) {
-      throw new LibraryLoadException(this.libName, t);
+      LibraryLoadException ex = new LibraryLoadException(this.libName, t);
+      this.listeners.onLoadFailure(this.platformSpec, this.optionalComponent, this.libName, ex);
+      throw ex;
     }
   }
 
   /** Provides a File to the library -- returns null for pre-loaded libraries */
   public final File toFile() {
-    return this.file;
+    return this.optionalFile;
   }
 
   /** Provides a Path to the library -- return null for pre-loaded libraries */
   public final Path toPath() {
-    return this.file == null ? null : this.file.toPath();
+    return this.optionalFile == null ? null : this.optionalFile.toPath();
   }
 
   /** Provides the an absolute path to the library -- returns null for pre-loaded libraries */
   public final String getAbsolutePath() {
-    return this.file == null ? null : this.file.getAbsolutePath();
+    return this.optionalFile == null ? null : this.optionalFile.getAbsolutePath();
   }
 
-  /** Schedules clean-up of underlying file -- if the file is a temp file */
+  /** Schedules clean-up of underlying optionalFile -- if the file is a temp file */
   @Override
   public void close() {
     if (this.needsCleanup) {
-      NativeLoader.delete(this.file);
+      boolean deleted = NativeLoader.delete(this.optionalFile);
+      if (deleted) {
+        this.listeners.onTempFileCleanup(
+            this.platformSpec, this.optionalComponent, this.libName, this.optionalFile.toPath());
+      }
     }
   }
 }

components/native-loader/src/main/java/datadog/nativeloader/LibraryLoadingListener.java

@@ -0,0 +1,53 @@
+package datadog.nativeloader;
+
+import java.net.URL;
+import java.nio.file.Path;
+
+public interface LibraryLoadingListener {
+  default void onResolveDynamic(
+      PlatformSpec platformSpec,
+      String optionalComponent,
+      String libName,
+      boolean isPreloaded,
+      URL optionalUrl) {}
+
+  default void onResolveDynamicFailure(
+      PlatformSpec platformSpec,
+      String optionalComponent,
+      String libName,
+      LibraryLoadException optionalCause) {}
+
+  default void onLoad(
+      PlatformSpec platformSpec,
+      String optionalComponent,
+      String libName,
+      boolean isPreloaded,
+      Path optionalLibPath) {}
+
+  default void onLoadFailure(
+      PlatformSpec platformSpec,
+      String optionalComponent,
+      String libName,
+      LibraryLoadException optionalCause) {}
+
+  default void onTempFileCreated(
+      PlatformSpec platformSpec, String optionalComponent, String libName, Path tempFile) {}
+
+  default void onTempFileCreationFailure(
+      PlatformSpec platformSpec,
+      String optionalComponent,
+      String libName,
+      Path tempDir,
+      String libExt,
+      Path optionalTempFile,
+      Throwable optionalCause) {}
+
+  default void onTempFileCleanup(
+      PlatformSpec platformSpec, String optionalComponent, String libName, Path tempFile) {}
+}
+
+abstract class SafeLibraryLoadingListener implements LibraryLoadingListener {
+  public abstract SafeLibraryLoadingListener join(LibraryLoadingListener... listeners);
+
+  public abstract boolean isNop();
+}