scm: git: backout r8839 (#8857)

call "git log" only once instead of per branch in fetching revisions.

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@9142 e93f8b46-1217-0410-a6f0-8f06a7374b81

app/models/repository/git.rb

@@ -107,7 +107,8 @@ class Repository::Git < Repository
   # However, Git does not have a sequential commit numbering.
   #
   # In order to fetch only new adding revisions,
-  # Redmine needs to save "heads".
+  # Redmine needs to parse revisions per branch.
+  # Branch "last_scmid" is for this requirement.
   #
   # In Git and Mercurial, revisions are not in date order.
   # Redmine Mercurial fixed issues.
@@ -130,17 +131,9 @@ class Repository::Git < Repository
   def fetch_changesets
     scm_brs = branches
     return if scm_brs.nil? || scm_brs.empty?
-
     h1 = extra_info || {}
     h  = h1.dup
-    repo_heads = scm_brs.map{ |br| br.scmid }
-    h["heads"] ||= []
-    prev_db_heads = h["heads"].dup
-    if prev_db_heads.empty?
-      prev_db_heads += heads_from_branches_hash
-    end
-    return if prev_db_heads.sort == repo_heads.sort
-
+    h["branches"]       ||= {}
     h["db_consistent"]  ||= {}
     if changesets.count == 0
       h["db_consistent"]["ordering"] = 1
@@ -151,39 +144,35 @@ class Repository::Git < Repository
       merge_extra_info(h)
       self.save
     end
-
-    save_revisions(prev_db_heads, repo_heads)
+    save_revisions(h, scm_brs)
   end
 
-  def save_revisions(prev_db_heads, repo_heads)
-    h = {}
-    opts = {}
-    opts[:reverse]  = true
-    opts[:excludes] = prev_db_heads
-    opts[:includes] = repo_heads
-    begin
-      scm.revisions('', nil, nil, opts) do |rev|
-        db_rev = find_changeset_by_name(rev.scmid)
-        transaction do
-          if db_rev.nil?
-            db_saved_rev = save_revision(rev)
-            parents = {}
-            parents[db_saved_rev] = rev.parents unless rev.parents.nil?
-            parents.each do |ch, chparents|
-              ch.parents = chparents.collect{|rp| find_changeset_by_name(rp)}.compact
+  def save_revisions(h, scm_brs)
+    scm_brs.each do |br1|
+      br = br1.to_s
+      from_scmid = nil
+      from_scmid = h["branches"][br]["last_scmid"] if h["branches"][br]
+      h["branches"][br] ||= {}
+      begin
+        scm.revisions('', from_scmid, br, {:reverse => true}) do |rev|
+          db_rev = find_changeset_by_name(rev.revision)
+          transaction do
+            if db_rev.nil?
+              db_saved_rev = save_revision(rev)
+              parents = {}
+              parents[db_saved_rev] = rev.parents unless rev.parents.nil?
+              parents.each do |ch, chparents|
+                ch.parents = chparents.collect{|rp| find_changeset_by_name(rp)}.compact
+              end
             end
+            h["branches"][br]["last_scmid"] = rev.scmid
+            merge_extra_info(h)
+            self.save
           end
-          h["heads"] = prev_db_heads.dup
-          h["heads"] << rev.scmid
-          merge_extra_info(h)
-          self.save
         end
+      rescue Redmine::Scm::Adapters::CommandFailed => e
+        logger.error("save revisions error: #{e.message}")
       end
-      h["heads"] = repo_heads.dup
-      merge_extra_info(h)
-      self.save
-    rescue Redmine::Scm::Adapters::CommandFailed => e
-      logger.error("save revisions error: #{e.message}")
     end
   end
   private :save_revisions