From d68aeacdd9cb632879de345a77de80d53baf4d04 Mon Sep 17 00:00:00 2001
From: jacksona <jacksona@google.com>
Date: Wed, 3 Jul 2019 09:31:41 -0700
Subject: [PATCH 1/2] add handicap support to the ast tree parser.

---
 cc/gtp_client.cc |  7 +++++--
 cc/sgf.cc        | 39 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 44 insertions(+), 2 deletions(-)

diff --git a/cc/gtp_client.cc b/cc/gtp_client.cc
index 6f06a7b61..d0f469dfa 100644
--- a/cc/gtp_client.cc
+++ b/cc/gtp_client.cc
@@ -179,11 +179,14 @@ void GtpClient::Ponder() {
 
 GtpClient::Response GtpClient::ReplaySgf(
     const std::vector<std::unique_ptr<sgf::Node>>& trees) {
+
   if (!trees.empty()) {
+    // the SGF parser takes care of transforming an sgf into moves that the
+    // engine is able to understand, so all we do here is just play them in.
     for (const auto& move : trees[0]->ExtractMainLine()) {
       if (!player_->PlayMove(move.c)) {
-        MG_LOG(ERROR) << "couldn't play move " << move.c;
-        return Response::Error("cannot load file");
+        MG_LOG(ERROR) << "Couldn't play move " << move.c;
+        return Response::Error("Cannot load file");
       }
     }
   }
diff --git a/cc/sgf.cc b/cc/sgf.cc
index d873b192a..2d4b7d995 100644
--- a/cc/sgf.cc
+++ b/cc/sgf.cc
@@ -210,6 +210,7 @@ bool GetTreeImpl(const Ast::Tree& tree,
                  std::vector<std::unique_ptr<Node>>* dst) {
   const auto* src = &tree;
   const Ast::Property* prop;
+  const Ast::Property* stones;
 
   // Extract all the nodes out of this tree.
   for (const auto& node : src->nodes) {
@@ -219,6 +220,44 @@ bool GetTreeImpl(const Ast::Tree& tree,
       move.color = Color::kBlack;
     } else if ((prop = node.FindProperty("W")) != nullptr) {
       move.color = Color::kWhite;
+    } else if ((prop = node.FindProperty("HA")) != nullptr) {
+      int handicap;
+      bool valid_handicap = absl::SimpleAtoi(prop->values[0], &handicap);
+      if (!valid_handicap) {
+        MG_LOG(ERROR) << "Invalid handicap property: " << prop->values[0];
+        break;
+      }
+
+      if ((handicap <= 1) || (handicap > 9)) {
+        MG_LOG(ERROR) << "Invalid handicap value:" << handicap;
+        return false;
+      }
+      stones = node.FindProperty("AB");
+      if (stones == nullptr) {
+        MG_LOG(ERROR) << "Handicap stones not specified.";
+        return false;
+      }
+
+      for (const auto& h_location : stones->values) {
+        Move m;
+        m.color = Color::kBlack;
+        m.c = Coord::FromSgf(h_location, true);
+        if (m.c == Coord::kInvalid) {
+          MG_LOG(ERROR) << "Can't parse node " << node.ToString() << ": \""
+                        << h_location << "\" isn't a valid SGF coord for a handicap stone";
+          return false;
+        }
+        std::string comment;
+        dst->push_back(absl::make_unique<Node>(m, std::move(comment)));
+        dst = &(dst->back()->children);
+        if (h_location != stones->values.back()) {
+          m.color = Color::kWhite;
+          m.c = Coord::kPass;
+          dst->push_back(absl::make_unique<Node>(m, std::move(comment)));
+          dst = &(dst->back()->children);
+        }
+      }
+      continue;
     } else {
       continue;
     }

From 8582d5ce488c5f846a0f5c7fec25d89293f776aa Mon Sep 17 00:00:00 2001
From: jacksona <jacksona@google.com>
Date: Wed, 3 Jul 2019 12:05:30 -0700
Subject: [PATCH 2/2] remove unused comment variable

---
 cc/sgf.cc | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/cc/sgf.cc b/cc/sgf.cc
index 2d4b7d995..85df11b5e 100644
--- a/cc/sgf.cc
+++ b/cc/sgf.cc
@@ -247,13 +247,12 @@ bool GetTreeImpl(const Ast::Tree& tree,
                         << h_location << "\" isn't a valid SGF coord for a handicap stone";
           return false;
         }
-        std::string comment;
-        dst->push_back(absl::make_unique<Node>(m, std::move(comment)));
+        dst->push_back(absl::make_unique<Node>(m, ""));
         dst = &(dst->back()->children);
         if (h_location != stones->values.back()) {
           m.color = Color::kWhite;
           m.c = Coord::kPass;
-          dst->push_back(absl::make_unique<Node>(m, std::move(comment)));
+          dst->push_back(absl::make_unique<Node>(m, ""));
           dst = &(dst->back()->children);
         }
       }