1 files changed, 63 insertions, 0 deletions
diff --git a/src/main/groovy/frege/gradle/plugins/FregeRuntime.java b/src/main/groovy/frege/gradle/plugins/FregeRuntime.java
new file mode 100644
index 0000000..4265d0b
--- /dev/null
+++ b/src/main/groovy/frege/gradle/plugins/FregeRuntime.java
@@ -0,0 +1,63 @@
+package frege.gradle.plugins;
+
+import com.google.common.collect.Lists;
+import org.gradle.api.Buildable;
+import org.gradle.api.GradleException;
+import org.gradle.api.Project;
+import org.gradle.api.artifacts.Dependency;
+import org.gradle.api.file.FileCollection;
+import org.gradle.api.internal.file.collections.LazilyInitializedFileCollection;
+import org.gradle.api.internal.tasks.TaskDependencyResolveContext;
+
+import java.io.File;
+import java.util.List;
+
+public class FregeRuntime {
+
+    private final Project project;
+
+    public FregeRuntime(Project project) {
+        this.project = project;
+    }
+
+
+    public FileCollection inferFregeClasspath(final Iterable<File> classpath) {
+        return new LazilyInitializedFileCollection() {
+            public String getDisplayName() {
+                return "Frege runtime classpath";
+            }
+
+            public FileCollection createDelegate() {
+                final FregeJarFile fregeJar = FregeRuntime.this.findFregeJarFile(classpath);
+                if (fregeJar == null) {
+                    throw new GradleException(String.format("Cannot infer Frege class path because no Frege Jar was found on class path: %s", classpath));
+                }
+                String notation = fregeJar.getDependencyNotation();
+                List<Dependency> dependencies = Lists.newArrayList();
+                dependencies.add(project.getDependencies().create(notation));
+                return project.getConfigurations().detachedConfiguration(dependencies.toArray(new Dependency[dependencies.size()]));
+            }
+
+            public void visitDependencies(TaskDependencyResolveContext context) {
+                if (classpath instanceof Buildable) {
+                    context.add(classpath);
+                }
+            }
+
+        };
+    }
+
+    private FregeJarFile findFregeJarFile(Iterable<File> classpath) {
+        if (classpath == null) {
+            return null;
+        }
+        for (File file : classpath) {
+            FregeJarFile fregeJar = FregeJarFile.parse(file);
+            if (fregeJar != null) {
+                return fregeJar;
+            }
+        }
+        return null;
+    }
+
+}