Add a way to override library paths using system properties

.github/workflows/checks.yml

@@ -55,7 +55,7 @@ jobs:
 
       - name: Run samples
         run: |
-          vips --version || brew install vips
+          vips --version || ((brew install pkgconf || brew link --overwrite pkgconf) && brew install vips)
           ./run_samples.sh
 
   windows-sense-check:

README.md

@@ -23,7 +23,7 @@ repositories {
 }
 
 dependencies {
-    implementation("app.photofox.vips-ffm:vips-ffm-core:1.2.2")
+    implementation("app.photofox.vips-ffm:vips-ffm-core:1.3.0")
 }
 ```
 When running your project you must add `--enable-native-access=ALL-UNNAMED` to your JVM runtime arguments. If you
@@ -172,6 +172,12 @@ yet (which could manifest as crashes/segfaults):
 * `vipsffm.abinumber.glib.override`, default: `0`
 * `vipsffm.abinumber.gobject.override`, default: `0`
 
+If you want to manually override the library lookup path for any of the above (for example, if you're using a platform
+like Android where it's hard to set the system library path), you can do so using these system properties:
+* libvips: `vipsffm.libpath.vips.override` (eg `/opt/homebrew/lib/libvips.dylib`)
+* glib: `vipsffm.libpath.glib.override`
+* gobject: `vipsffm.libpath.gobject.override`
+
 ## Project goals
 
 Ideas and suggestions are welcome, but please make sure they fit in to these goals, or you have a good argument about

core/src/main/java/app/photofox/vipsffm/VipsLibLookup.java

@@ -2,6 +2,7 @@
 
 import java.lang.foreign.Arena;
 import java.lang.foreign.SymbolLookup;
+import java.nio.file.Path;
 import java.util.List;
 import java.util.Optional;
 
@@ -25,6 +26,10 @@ public static SymbolLookup buildSymbolLoader(Arena arena) {
     }
 
     private static SymbolLookup findVipsLoader(Arena arena) {
+        var overrideLookup = makeOptionalLibraryLookup("vips", arena);
+        if (overrideLookup.isPresent()) {
+            return overrideLookup.get();
+        }
         var abiNumber = Optional.ofNullable(System.getProperty("vipsffm.abinumber.vips.override"))
             .orElse("42");
         var names = List.of(
@@ -36,6 +41,10 @@ private static SymbolLookup findVipsLoader(Arena arena) {
     }
 
     private static SymbolLookup findGlibLoader(Arena arena) {
+        var overrideLookup = makeOptionalLibraryLookup("glib", arena);
+        if (overrideLookup.isPresent()) {
+            return overrideLookup.get();
+        }
         var abiNumber = Optional.ofNullable(System.getProperty("vipsffm.abinumber.glib.override"))
             .orElse("0");
         var names = List.of(
@@ -47,6 +56,10 @@ private static SymbolLookup findGlibLoader(Arena arena) {
     }
 
     private static SymbolLookup findGObjectLoader(Arena arena) {
+        var overrideLookup = makeOptionalLibraryLookup("gobject", arena);
+        if (overrideLookup.isPresent()) {
+            return overrideLookup.get();
+        }
         var abiNumber = Optional.ofNullable(System.getProperty("vipsffm.abinumber.gobject.override"))
             .orElse("0");
         var names = List.of(
@@ -79,4 +92,26 @@ static Optional<SymbolLookup> attemptLibraryLookup(String name, Arena arena) {
             return Optional.empty();
         }
     }
+
+    private static Optional<SymbolLookup> makeOptionalLibraryLookup(String libraryName, Arena arena) {
+        var propertyPath = "vipsffm.libpath.%s.override".formatted(libraryName);
+        var overridePath = Optional.ofNullable(System.getProperty(propertyPath));
+        return overridePath.map(path -> {
+            SymbolLookup symbolLookup;
+            try {
+                symbolLookup = SymbolLookup.libraryLookup(Path.of(path), arena);
+            } catch (IllegalArgumentException exception) {
+                throw makeOverriddenPathMissingException(libraryName, path);
+            }
+            return symbolLookup;
+        });
+    }
+
+    private static IllegalArgumentException makeOverriddenPathMissingException(
+        String libraryName,
+        String overridePath
+    ) {
+        var message = "path override requested for %s, but library not found at path: %s".formatted(libraryName, overridePath);
+        return new IllegalArgumentException(message);
+    }
 }

docs/index.html

@@ -70,7 +70,7 @@ <h2 id="usage-heading">Usage</h2>
 }
 
 dependencies {
-    implementation(&quot;app.photofox.vips-ffm:vips-ffm-core:1.2.2&quot;)
+    implementation(&quot;app.photofox.vips-ffm:vips-ffm-core:1.3.0&quot;)
 }
 </code></pre>
 <p>When running your project you must add <code>--enable-native-access=ALL-UNNAMED</code> to your JVM runtime arguments. If you
@@ -122,8 +122,7 @@ <h3 id="thumbnail-sample-heading">Thumbnail sample</h3>
 Vips.run { arena -&gt;
     val sourceImage = VImage.newFromFile(
       arena,
-      &quot;sample/src/main/resources/sample_images/rabbit.jpg&quot;,
-      VipsOption.Enum(&quot;access&quot;, VipsAccess.ACCESS_SEQUENTIAL) // example of an option
+      &quot;sample/src/main/resources/sample_images/rabbit.jpg&quot;
     )
     val sourceWidth = sourceImage.width
     val sourceHeight = sourceImage.height
@@ -132,9 +131,9 @@ <h3 id="thumbnail-sample-heading">Thumbnail sample</h3>
     val outputPath = workingDirectory.resolve(&quot;rabbit_copy.jpg&quot;)
     sourceImage.writeToFile(outputPath.absolutePathString())
 
-    val thumbnail = sourceImage.thumbnail(
-      &quot;sample/src/main/resources/sample_images/rabbit.jpg&quot;,
-      400
+    val thumbnail = sourceImage.thumbnailImage(
+      400,
+      VipsOption.Boolean(&quot;auto-rotate&quot;, true) // example of an option
     )
     val thumbnailWidth = thumbnail.width
     val thumbnailHeight = thumbnail.height
@@ -218,6 +217,13 @@ <h2 id="native-library-loading-heading">Native library loading</h2>
 <li><code>vipsffm.abinumber.glib.override</code>, default: <code>0</code></li>
 <li><code>vipsffm.abinumber.gobject.override</code>, default: <code>0</code></li>
 </ul>
+<p>If you want to manually override the library lookup path for any of the above (for example, if you're using a platform
+like Android where it's hard to set the system library path), you can do so using these system properties:</p>
+<ul>
+<li>libvips: <code>vipsffm.libpath.vips.override</code> (eg <code>/opt/homebrew/lib/libvips.dylib</code>)</li>
+<li>glib: <code>vipsffm.libpath.glib.override</code></li>
+<li>gobject: <code>vipsffm.libpath.gobject.override</code></li>
+</ul>
 <h2 id="project-goals-heading">Project goals</h2>
 <p>Ideas and suggestions are welcome, but please make sure they fit in to these goals, or you have a good argument about
 why a goal should change!</p>

run_samples.sh

@@ -4,12 +4,15 @@ set -eou pipefail
 echo "building samples..."
 ./gradlew sample:clean sample:shadowJar
 
+export JAVA_PATH_OPTS=""
 if [[ "$OSTYPE" == "darwin"* ]]; then
   export DYLD_LIBRARY_PATH=/opt/homebrew/lib
+  # this tests the library path override feature
+  export JAVA_PATH_OPTS="-Dvipsffm.libpath.vips.override=/opt/homebrew/lib/libvips.dylib"
 fi
 
 echo "running samples..."
-java -jar sample/build/libs/sample-all.jar 2>&1 | tee sample_output.log
+java $JAVA_PATH_OPTS -jar sample/build/libs/sample-all.jar 2>&1 | tee sample_output.log
 
 echo "checking for leaks..."
 if grep --quiet "objects alive:" sample_output.log; then