Cache result of nativeLink

So that it won't be run again if no input file has changed and if none of the relevant scala-native options has changed.
scala-native · Nov 22, 2016 · d7078df · d7078df
1 parent e5811ba
commit d7078df
Showing 1 changed file with 43 additions and 11 deletions.
diff --git a/sbtplugin/src/main/scala/scala/scalanative/sbtplugin/ScalaNativePluginInternal.scala b/sbtplugin/src/main/scala/scala/scalanative/sbtplugin/ScalaNativePluginInternal.scala
@@ -170,17 +170,44 @@ object ScalaNativePluginInternal {
 
       checkThatClangIsRecentEnough(clang)
 
-      IO.createDirectory(target)
-      val unpackSuccess = unpackRtlib(clang, clangpp, classpath)
-
-      if (unpackSuccess) {
-        val links = compileNir(opts).map(_.name)
-        compileLl(clangpp, target, appll, binary, links, linkage, clangOpts)
-
-        binary
-      } else {
-        throw new MessageOnlyException("Couldn't unpack nativelib.")
-      }
+      val nirFiles   = (Keys.target.value ** "*.nir").get.toSet
+      val configFile = (streams.value.cacheDirectory / "native-config")
+      val inputFiles = nirFiles + configFile
+
+      writeConfigHash(configFile,
+                      opts,
+                      clang,
+                      clangpp,
+                      classpath,
+                      target,
+                      appll,
+                      binary,
+                      linkage,
+                      clangOpts)
+
+      val compileIfChanged =
+        FileFunction.cached(streams.value.cacheDirectory / "native-cache",
+                            FilesInfo.hash) {
+          _ =>
+            IO.createDirectory(target)
+            val unpackSuccess = unpackRtlib(clang, clangpp, classpath)
+            if (unpackSuccess) {
+              val links = compileNir(opts).map(_.name)
+              compileLl(clangpp,
+                        target,
+                        appll,
+                        binary,
+                        links,
+                        linkage,
+                        clangOpts)
+              Set(binary)
+            } else {
+              throw new MessageOnlyException("Couldn't unpack nativelib.")
+            }
+        }
+
+      val _ = compileIfChanged(inputFiles)
+      binary
     },
     run := {
       val log    = streams.value.log
@@ -198,6 +225,11 @@ object ScalaNativePluginInternal {
     }
   )
 
+  private def writeConfigHash(file: File, config: Any*): Unit = {
+    val _ = config.## // Force evaluation of lazy structures
+    IO.write(file, Hash(config.toString))
+  }
+
   private def maybeInjectShared(lib: Boolean): Seq[String] =
     if (lib) Seq("-shared") else Seq.empty