Don't store current branch in GitBranchesCollection

Reason: GitBranchesCollection is updated more less frequently that the current branch.
Current branch is accessible from GitRepository#getCurrentBranch()

plugins/git4idea/src/git4idea/branch/GitBranchesCollection.java

@@ -17,7 +17,6 @@ package git4idea.branch;
 
 import git4idea.GitBranch;
 import org.jetbrains.annotations.NotNull;
-import org.jetbrains.annotations.Nullable;
 
 import java.util.Collection;
 import java.util.Collections;
@@ -36,14 +35,12 @@ import java.util.HashSet;
  */
 public final class GitBranchesCollection {
   
-  public static final GitBranchesCollection EMPTY = new GitBranchesCollection(null, Collections.<GitBranch>emptyList(), Collections.<GitBranch>emptyList());
+  public static final GitBranchesCollection EMPTY = new GitBranchesCollection(Collections.<GitBranch>emptyList(), Collections.<GitBranch>emptyList());
 
   private final Collection<GitBranch> myLocalBranches;
   private final Collection<GitBranch> myRemoteBranches;
-  private final GitBranch myCurrentBranch;
 
-  public GitBranchesCollection(@Nullable GitBranch currentBranch, @NotNull Collection<GitBranch> localBranches, @NotNull Collection<GitBranch> remoteBranches) {
-    myCurrentBranch = currentBranch;
+  public GitBranchesCollection(@NotNull Collection<GitBranch> localBranches, @NotNull Collection<GitBranch> remoteBranches) {
     myRemoteBranches = remoteBranches;
     myLocalBranches = localBranches;
   }
@@ -52,7 +49,7 @@ public final class GitBranchesCollection {
    * Copy constructor. Sets inside are also copied.
    */
   public GitBranchesCollection(@NotNull GitBranchesCollection branches) {
-    this(branches.getCurrentBranch(), branches.getLocalBranches(), branches.getRemoteBranches());
+    this(branches.getLocalBranches(), branches.getRemoteBranches());
   }
 
   /**
@@ -71,12 +68,4 @@ public final class GitBranchesCollection {
     return new HashSet<GitBranch>(myRemoteBranches);
   }
 
-  /**
-   * @return currently active branch.
-   *         Current branch may be <code>null</code> in the case of detached head,
-   */
-  @Nullable
-  public GitBranch getCurrentBranch() {
-    return myCurrentBranch;
-  }
 }

plugins/git4idea/src/git4idea/history/browser/CachedRefs.java

@@ -31,6 +31,7 @@ import java.util.*;
  */
 public class CachedRefs implements SymbolicRefsI {
   private GitBranchesCollection myCollection;
+  private GitBranch myCurrentBranch;
   private String myTrackedRemoteName;
   private String myUsername;
   private AbstractHash myHeadHash;
@@ -44,6 +45,10 @@ public class CachedRefs implements SymbolicRefsI {
     myRefsMap = new MultiMap<String, Pair<SymbolicRefs.Kind, String>>();
   }
 
+  public void setCurrentBranch(GitBranch currentBranch) {
+    myCurrentBranch = currentBranch;
+  }
+
   public void setCollection(GitBranchesCollection collection) {
     myCollection = collection;
     /*GitBranch branch = myCollection.getCurrentBranch();
@@ -109,13 +114,12 @@ public class CachedRefs implements SymbolicRefsI {
 
   @Override
   public String getCurrentName() {
-    GitBranch branch = myCollection.getCurrentBranch();
-    return branch == null ? null : branch.getName();
+    return myCurrentBranch == null ? null : myCurrentBranch.getName();
   }
 
   @Override
   public GitBranch getCurrent() {
-    return myCollection.getCurrentBranch();
+    return myCurrentBranch;
   }
 
   @Override

plugins/git4idea/src/git4idea/history/browser/LowLevelAccessImpl.java

@@ -115,21 +115,19 @@ public class LowLevelAccessImpl implements LowLevelAccess {
   // uses cached version
   public CachedRefs getRefs() throws VcsException {
     final CachedRefs refs = new CachedRefs();
-    final GitRepository repositoryForRoot = GitUtil.getRepositoryManager(myProject).getRepositoryForRoot(myRoot);
-    final GitBranchesCollection branches;
-    if (repositoryForRoot != null) {
-      branches = repositoryForRoot.getBranches();
-    } else {
+    GitRepository repository = GitUtil.getRepositoryManager(myProject).getRepositoryForRoot(myRoot);
+    if (repository == null) {
       final File child = new File(myRoot.getPath(), ".git");
       if (! child.exists()) {
         throw new VcsException("No git repository in " + myRoot.getPath());
       }
-      GitRepository repository = GitRepository.getLightInstance(myRoot, myProject, myProject);
+      repository = GitRepository.getLightInstance(myRoot, myProject, myProject);
       repository.getBranches();
-      branches = repository.getBranches();
     }
+    GitBranchesCollection branches = repository.getBranches();
     refs.setCollection(branches);
-    final GitBranch current = branches.getCurrentBranch();
+    final GitBranch current = repository.getCurrentBranch();
+    refs.setCurrentBranch(current);
     if (current != null) {
       GitBranch tracked = current.tracked(myProject, myRoot);
       String fullName = tracked == null ? null : tracked.getFullName();

plugins/git4idea/src/git4idea/repo/GitRepositoryReader.java

@@ -260,7 +260,7 @@ class GitRepositoryReader {
     GitBranch currentBranch = readCurrentBranch();
     markActiveBranch(localBranches, currentBranch);
 
-    return new GitBranchesCollection(currentBranch, localBranches, remoteBranches);
+    return new GitBranchesCollection(localBranches, remoteBranches);
   }
   
   /**
@@ -356,7 +356,7 @@ class GitRepositoryReader {
         }
       });
     }
-    return new GitBranchesCollection(null, localBranches, remoteBranches);
+    return new GitBranchesCollection(localBranches, remoteBranches);
   }
 
     

plugins/git4idea/tests/git4idea/repo/GitRepositoryReaderTest.java

@@ -72,7 +72,7 @@ public class GitRepositoryReaderTest extends LightIdeaTestCase {
   
   public void testBranches(){
     GitBranchesCollection branchesCollection = myRepositoryReader.readBranches();
-    GitBranch currentBranch = branchesCollection.getCurrentBranch();
+    GitBranch currentBranch = myRepositoryReader.readCurrentBranch();
     Collection<GitBranch> localBranches = branchesCollection.getLocalBranches();
     Collection<GitBranch> remoteBranches = branchesCollection.getRemoteBranches();