implement tunable for suppressing history fetch other than from the cache

fixes #446

Author: vladak

src/org/opensolaris/opengrok/configuration/RuntimeEnvironment.java

@@ -887,6 +887,16 @@ public void setChattyStatusPage(boolean chatty) {
         threadConfig.get().setChattyStatusPage(chatty);
     }
 
+    public boolean noFetchHistoryWhenNotInCache() {
+        String enabled =
+            System.getProperty("org.opensolaris.opengrok.history.noFetchWhenNotInCache");
+        if (enabled != null) {
+            return true;
+        }
+
+        return (false);
+    }
+    
     /**
      * Read an configuration file and set it as the current configuration.
      *

src/org/opensolaris/opengrok/history/FileHistoryCache.java

@@ -63,6 +63,17 @@ class FileHistoryCache implements HistoryCache {
     private final Object lock = new Object();
     private String historyCacheDirName = "historycache";
     private String latestRevFileName = "OpenGroklatestRev";
+    private boolean historyIndexDone = false;
+    
+    @Override
+    public void setHistoryIndexDone() {
+        historyIndexDone = true;
+    }
+
+    @Override
+    public boolean isHistoryIndexDone() {
+        return historyIndexDone;
+    }
 
     /**
      * Generate history for single file.
@@ -445,6 +456,13 @@ public History get(File file, Repository repository, boolean withFiles)
             }
         }
 
+        // Some repository checkouts may contain lots of files untracked by
+        // given SCM. For these it would be waste of time to get their history.
+        RuntimeEnvironment env = RuntimeEnvironment.getInstance();
+        if (isHistoryIndexDone() && env.noFetchHistoryWhenNotInCache()) {
+            return null;
+        }
+
         final History history;
         long time;
         try {
@@ -464,7 +482,6 @@ public History get(File file, Repository repository, boolean withFiles)
             // a sub-directory change. This will cause us to present a stale
             // history log until a the current directory is updated and
             // invalidates the cache entry.
-            RuntimeEnvironment env = RuntimeEnvironment.getInstance();
             if ((cache != null) &&
                         (cache.exists() ||
                              (time > env.getHistoryReaderTimeLimit()))) {

src/org/opensolaris/opengrok/history/HistoryCache.java

@@ -18,7 +18,7 @@
  */
 
 /*
- * Copyright (c) 2006, 2012, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2006, 2014, Oracle and/or its affiliates. All rights reserved.
  */
 package org.opensolaris.opengrok.history;
 
@@ -27,7 +27,6 @@
 import java.util.Map;
 
 interface HistoryCache {
-
     /**
      * Create and initialize an empty history cache if one doesn't exist
      * already.
@@ -133,4 +132,8 @@ Map<String, Date> getLastModifiedTimes(
      * @throws HistoryException if an error occurred while getting the info
      */
     String getInfo() throws HistoryException;
+
+    // Set and query if history index phase is done.
+    void setHistoryIndexDone();
+    boolean isHistoryIndexDone();
 }

src/org/opensolaris/opengrok/history/HistoryGuru.java

@@ -18,7 +18,7 @@
  */
 
 /*
- * Copyright (c) 2005, 2012, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2005, 2014, Oracle and/or its affiliates. All rights reserved.
  */
 package org.opensolaris.opengrok.history;
 
@@ -162,8 +162,7 @@ public Annotation annotate(File file, String rev) throws IOException {
     }
 
     /**
-     * Get the appropriate history reader for the file specified by parent and
-     * basename.
+     * Get the appropriate history reader for given file.
      *
      * @param file The file to get the history reader for
      * @throws HistoryException If an error occurs while getting the history
@@ -601,6 +600,7 @@ public void run() {
         String time_str = StringUtils.getReadableTime(stop - start);
         log.log(Level.INFO, "Done historycache for all repositories (took {0})",
             time_str);
+        historyCache.setHistoryIndexDone();
     }
 
     public void createCache(Collection<String> repositories) {

src/org/opensolaris/opengrok/history/JDBCHistoryCache.java

@@ -57,6 +57,8 @@
 
 class JDBCHistoryCache implements HistoryCache {
 
+    private boolean historyIndexDone = false;
+
     /** The schema in which the tables live. */
     private static final String SCHEMA = "OPENGROK";
 
@@ -1384,4 +1386,14 @@ private void doRenamedHistory(final Repository repository, File file,
             }
         }
     }
+
+    @Override
+    public void setHistoryIndexDone() {
+        historyIndexDone = true;
+    }
+
+    @Override
+    public boolean isHistoryIndexDone() {
+        return historyIndexDone;
+    }
 }