Added revalidate_policy config.

This allows resources to be validated prior to every app launch instead of just
after update.

Also fixed some erroneous logging.

CHANGELOG.md

@@ -18,6 +18,11 @@
   without a proxy, it does so for that session, but retains the proxy config for future sessions in
   which the proxy may again be needed.
 
+* Added `revalidate_policy` config to control when Getdown revalidates resources (by hashing them
+  and comparing that hash to the values in `digest.txt`). The default, `after_update`, only
+  validates resources after the app is updated. A new mode, `always`, validates resources prior to
+  every application launch.
+
 ## 1.8.4 - May 14, 2019
 
 * Added `verify_timeout` config to allow customization of the default (60 second) timeout during

core/src/main/java/com/threerings/getdown/data/Application.java

@@ -636,21 +636,18 @@ public class Application
             }
         }
 
-        // determine whether we want strict comments
+        // read some miscellaneous configurations
         _strictComments = config.getBoolean("strict_comments");
-
-        // determine whether we want to allow offline operation (defaults to false)
         _allowOffline = config.getBoolean("allow_offline");
+        _revalidatePolicy = config.getEnum(
+            "revalidate_policy", RevalidatePolicy.class, RevalidatePolicy.AFTER_UPDATE);
+        int tpSize = SysProps.threadPoolSize();
+        _maxConcDownloads = Math.max(1, config.getInt("max_concurrent_downloads", tpSize));
+        _verifyTimeout = config.getInt("verify_timeout", 60);
 
         // whether to cache code resources and launch from cache
         _useCodeCache = config.getBoolean("use_code_cache");
         _codeCacheRetentionDays = config.getInt("code_cache_retention_days", 7);
-
-        // maximum simultaneous downloads
-        _maxConcDownloads = Math.max(1, config.getInt("max_concurrent_downloads",
-                                                      SysProps.threadPoolSize()));
-
-        _verifyTimeout = config.getInt("verify_timeout", 60);
     }
 
     /**
@@ -1361,14 +1358,14 @@ public class Application
         unpacked.addAll(unpackedAsync);
 
         long complete = System.currentTimeMillis();
-        log.info("Verified resources", "count", rsrcs.size(), "size", (totalSize/1024) + "k",
+        log.info("Verified resources", "count", rsrcs.size(), "alreadyValid", alreadyValid[0],
-                 "duration", (complete-start) + "ms");
+                 "size", (totalSize/1024) + "k", "duration", (complete-start) + "ms");
     }
 
     private void verifyResource (Resource rsrc, ProgressObserver obs, int[] alreadyValid,
                                  Set<Resource> unpacked,
                                  Set<Resource> toInstall, Set<Resource> toDownload) {
-        if (rsrc.isMarkedValid()) {
+        if (_revalidatePolicy != RevalidatePolicy.ALWAYS && rsrc.isMarkedValid()) {
             if (alreadyValid != null) {
                 alreadyValid[0]++;
             }
@@ -1765,6 +1762,7 @@ public class Application
 
     protected int _verifyTimeout = 60;
 
+    protected RevalidatePolicy _revalidatePolicy = RevalidatePolicy.AFTER_UPDATE;
     protected boolean _useCodeCache;
     protected int _codeCacheRetentionDays;
 
@@ -1790,4 +1788,6 @@ public class Application
 
     protected static final String ENV_VAR_PREFIX = "%ENV.";
     protected static final Pattern ENV_VAR_PATTERN = Pattern.compile("%ENV\\.(.*?)%");
+
+    protected static enum RevalidatePolicy { ALWAYS, AFTER_UPDATE }
 }

core/src/main/java/com/threerings/getdown/util/Config.java

@@ -247,6 +247,20 @@ public class Config
         return Boolean.parseBoolean(getString(name));
     }
 
+    /**
+     * Returns the specified config value as an enum value. The string value of the config is
+     * converted to all upper case and then turned into an enum via {@link Enum#valueOf}.
+     */
+    public <T extends Enum<T>> T getEnum (String name, Class<T> eclass, T defval) {
+        String value = getString(name, defval.toString());
+        try {
+            return Enum.valueOf(eclass, value.toUpperCase());
+        } catch (Exception e) {
+            log.warning("Invalid value for '" + name + "' config: '" + value + "'.");
+            return defval;
+        }
+    }
+
     /**
      * Massages a single string into an array and leaves existing array values as is. Simplifies
      * access to parameters that are expected to be arrays.

launcher/src/main/java/com/threerings/getdown/launcher/Getdown.java

@@ -129,7 +129,7 @@ public abstract class Getdown
     {
         if (SysProps.noInstall()) {
             log.info("Skipping install due to 'no_install' sysprop.");
-        } else if (_readyToInstall) {
+        } else if (isUpdateAvailable()) {
             log.info("Installing " + _toInstallResources.size() + " downloaded resources:");
             for (Resource resource : _toInstallResources) {
                 resource.install(true);
@@ -260,13 +260,15 @@ public abstract class Getdown
             }
         }
 
-        try {
+        if (!predownloads.isEmpty()) {
-            download(predownloads);
+            try {
-            for (Resource rsrc : predownloads) {
+                download(predownloads);
-                rsrc.install(false); // install but don't validate yet
+                for (Resource rsrc : predownloads) {
+                    rsrc.install(false); // install but don't validate yet
+                }
+            } catch (IOException ioe) {
+                log.warning("Failed to predownload resources. Continuing...", ioe);
             }
-        } catch (IOException ioe) {
-            log.warning("Failed to predownload resources. Continuing...", ioe);
         }
     }