[vcs-log] add VcsLogProperty for determining whether log provider supports indexing, introduce registry key to enable it for Git

platform/util/resources/misc/registry.properties

@@ -300,6 +300,8 @@ vcs.log.labels.redesign=false
 vcs.log.labels.redesign.description=Show branch labels on the right with combined tag icons, do not display tag names, combine tracked branches, display detached heads with an exclamation mark
 vcs.log.highlight.not.indexed=false
 vcs.log.highlight.not.indexed.description=Highlight commits that are not indexed
+vcs.log.index.git=false
+vcs.log.index.git.description=Index all commits in Git repository for fast search
 
 vcs.executable.validator.timeout.sec=60
 vcs.unversioned.files.in.commit=true

platform/vcs-log/api/src/com/intellij/vcs/log/VcsLogProperties.java

@@ -27,6 +27,7 @@ public class VcsLogProperties {
   }
 
   @NotNull public static final VcsLogProperty<Boolean> LIGHTWEIGHT_BRANCHES = new VcsLogProperty<>(false);
+  @NotNull public static final VcsLogProperty<Boolean> SUPPORTS_INDEXING = new VcsLogProperty<>(false);
 
   @NotNull
   public static <T> T get(@NotNull VcsLogProvider provider, VcsLogProperty<T> property) {

platform/vcs-log/impl/src/com/intellij/vcs/log/data/index/VcsLogPersistentIndex.java

@@ -86,7 +86,13 @@ public class VcsLogPersistentIndex implements VcsLogIndex, Disposable {
     myProject = project;
     myProviders = providers;
     myFatalErrorsConsumer = fatalErrorsConsumer;
-    myRoots = providers.keySet();
+    myRoots = ContainerUtil.newLinkedHashSet();
+
+    for (Map.Entry<VirtualFile, VcsLogProvider> entry : providers.entrySet()) {
+      if (VcsLogProperties.get(entry.getValue(), VcsLogProperties.SUPPORTS_INDEXING)) {
+        myRoots.add(entry.getKey());
+      }
+    }
 
     myUserRegistry = (VcsUserRegistryImpl)ServiceManager.getService(myProject, VcsUserRegistry.class);
 
@@ -194,12 +200,12 @@ public class VcsLogPersistentIndex implements VcsLogIndex, Disposable {
 
   @Override
   public synchronized boolean isIndexed(@NotNull VirtualFile root) {
-    return !myCommitsToIndex.containsKey(root) && myNumberOfTasks.get(root).get() == 0;
+    return myRoots.contains(root) && (!myCommitsToIndex.containsKey(root) && myNumberOfTasks.get(root).get() == 0);
   }
 
   @Override
   public synchronized void markForIndexing(int index, @NotNull VirtualFile root) {
-    if (isIndexed(index)) return;
+    if (isIndexed(index) || !myRoots.contains(root)) return;
     TIntHashSet set = myCommitsToIndex.get(root);
     if (set == null) {
       set = new TIntHashSet();

plugins/git4idea/src/git4idea/log/GitLogProvider.java

@@ -20,6 +20,7 @@ import com.intellij.openapi.diagnostic.Attachment;
 import com.intellij.openapi.diagnostic.Logger;
 import com.intellij.openapi.project.Project;
 import com.intellij.openapi.util.ThrowableNotNullFunction;
+import com.intellij.openapi.util.registry.Registry;
 import com.intellij.openapi.util.text.StringUtil;
 import com.intellij.openapi.vcs.FilePath;
 import com.intellij.openapi.vcs.VcsException;
@@ -518,12 +519,16 @@ public class GitLogProvider implements VcsLogProvider {
     return currentBranchName;
   }
 
+  @SuppressWarnings("unchecked")
   @Nullable
   @Override
   public <T> T getPropertyValue(VcsLogProperties.VcsLogProperty<T> property) {
     if (property == VcsLogProperties.LIGHTWEIGHT_BRANCHES) {
       return (T)Boolean.TRUE;
     }
+    else if (property == VcsLogProperties.SUPPORTS_INDEXING) {
+      return (T)Boolean.valueOf(Registry.is("vcs.log.index.git"));
+    }
     return null;
   }