Don't install artifacts that have already been installed unless the --override option is present

Author: SamCarlberg

src/main/java/edu/wpi/first/wpilib/opencv/installer/ArtifactType.java

@@ -0,0 +1,31 @@
+package edu.wpi.first.wpilib.opencv.installer;
+
+import lombok.Getter;
+import lombok.RequiredArgsConstructor;
+
+@Getter
+@RequiredArgsConstructor
+public enum ArtifactType {
+
+    /**
+     * The artifact type for the Java library.
+     */
+    JAVA("Java library"),
+
+    /**
+     * The artifact type for the JNI bindings.
+     */
+    JNI("JNI bindings"),
+
+    /**
+     * The artifact type for the C++ headers.
+     */
+    HEADERS("C++ headers"),
+
+    /**
+     * The artifact type for the C++ native libraries.
+     */
+    NATIVES("C++ native libraries");
+
+    private final String artifactName;
+}

src/main/java/edu/wpi/first/wpilib/opencv/installer/InstallChecker.java

@@ -0,0 +1,37 @@
+package edu.wpi.first.wpilib.opencv.installer;
+
+import lombok.experimental.UtilityClass;
+
+import java.util.prefs.Preferences;
+
+/**
+ * Utility class for checking if artifacts have already been installed.
+ */
+@UtilityClass
+public class InstallChecker {
+
+    private static final Preferences prefs = Preferences.userNodeForPackage(InstallChecker.class);
+
+    /**
+     * Checks if the given artifact type has already been installed by this app.
+     *
+     * @param which   the artifact type to check
+     * @param version the version of OpenCV to check for
+     *
+     * @return true if the given artifact has already been installed, false if it has not
+     */
+    public static boolean isInstalled(ArtifactType which, String version) {
+        return prefs.node(version).getBoolean(which.name(), false);
+    }
+
+    /**
+     * Sets the given artifact type as having been successfully installed.
+     *
+     * @param which   the artifact type that was installed
+     * @param version the version of OpenCV the artifact is for
+     */
+    public static void registerSuccessfulInstall(ArtifactType which, String version) {
+        prefs.node(version).putBoolean(which.name(), true);
+    }
+
+}

src/main/java/edu/wpi/first/wpilib/opencv/installer/Installer.java

@@ -51,13 +51,6 @@ public class Installer {
     private static String openCvVersion = "";
     private static String version = "";
 
-    private enum ArtifactType {
-        JAVA, // This one has special cases because the jar isn't packaged, so unzipping it would just output a ton of class files
-        JNI,
-        HEADERS,
-        NATIVES
-    }
-
 
     /**
      * Main entry point.
@@ -87,7 +80,7 @@ public static void main(String[] args) throws ParseException {
         if (parsedArgs.hasOption("platform")) {
             setPlatform(Platform.valueOf(parsedArgs.getOptionValue("platform")));
         }
-        setVersion(parsedArgs.getOptionValue("version"));
+        setOpenCvVersion(parsedArgs.getOptionValue("version"));
         overwrite = parsedArgs.hasOption("overwrite");
         System.out.println("Installing specified OpenCV components");
         if (parsedArgs.hasOption("java") || parsedArgs.hasOption("all")) {
@@ -127,7 +120,7 @@ public static void setPlatform(Platform p) {
      *
      * @param v the version of OpenCV to install
      */
-    public static void setVersion(String v) {
+    public static void setOpenCvVersion(String v) {
         openCvVersion = v;
         calculateVersion();
     }
@@ -136,6 +129,15 @@ private static void calculateVersion() {
         version = platform + "-" + openCvVersion;
     }
 
+    /**
+     * Gets the version of OpenCV being installed.
+     *
+     * @return the version of OpenCV being installed
+     */
+    public static String getOpenCvVersion() {
+        return openCvVersion;
+    }
+
     /**
      * Downloads the Java API jar.
      */
@@ -177,6 +179,12 @@ public static void installNatives() {
     }
 
     private static void install(ArtifactType type) {
+        if (!overridePlatform && InstallChecker.isInstalled(type, openCvVersion)) {
+            System.out.println("Artifacts for the version " + openCvVersion + " " + type.getArtifactName() + " have already been installed!");
+            if (!overwrite) {
+                return;
+            }
+        }
         try {
             String artifactId;
             String v = version;
@@ -231,6 +239,7 @@ private static void install(ArtifactType type) {
                 unzipped = dst.getParent();
             }
             copyAll(unzipped, Paths.get(installLocation));
+            InstallChecker.registerSuccessfulInstall(type, openCvVersion);
         } catch (Exception e) {
             e.printStackTrace(System.out);
         }
@@ -252,6 +261,7 @@ private static String resolveRelative(String repo, String artifactId, String ver
      * Unzips the given zip file
      *
      * @param zipFile the file to unzip
+     *
      * @return the directory that the file was unzipped into
      */
     private static Path unzip(File zipFile) {
@@ -282,6 +292,7 @@ private static Path unzip(File zipFile) {
      *
      * @param sourceDir the directory holding the files to copy
      * @param dstDir    the directory to copy the files into
+     *
      * @throws IOException if the source directory is unreadable
      */
     private static void copyAll(Path sourceDir, Path dstDir) throws IOException {