SuperSize: Fix method count mode for size diffs

It was not filtering out changed symbols.

Bug: 1040165
Change-Id: I85c0898788708defda595ccb1f25a5a97d94aa46
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2032806
Commit-Queue: Andrew Grieve <agrieve@chromium.org>
Reviewed-by: Samuel Huang <huangs@chromium.org>
Cr-Commit-Position: refs/heads/master@{#737846}

tools/binary_size/libsupersize/caspian/caspian_web.cc

@@ -91,6 +91,16 @@ bool BuildTree(bool method_count_mode,
 
   const bool diff_mode = info && before_info;
 
+  if (method_count_mode && diff_mode) {
+    // include_sections is used to filter to just .dex.method symbols.
+    // For diffs, we also want to filter to just adds & removes.
+    filters.push_back([](const GroupedPath&, const BaseSymbol& sym) -> bool {
+      DiffStatus diff_status = sym.GetDiffStatus();
+      return diff_status == DiffStatus::kAdded ||
+             diff_status == DiffStatus::kRemoved;
+    });
+  }
+
   if (minimum_size_bytes > 0) {
     if (!diff_mode) {
       filters.push_back([minimum_size_bytes](const GroupedPath&,

tools/binary_size/libsupersize/caspian/model.cc

@@ -326,6 +326,7 @@ void TreeNode::WriteIntoJson(
     std::function<bool(const TreeNode* const& l, const TreeNode* const& r)>
         compare_func,
     bool is_sparse,
+    bool method_count_mode,
     Json::Value* out) {
   if (symbol) {
     (*out)["helpme"] = std::string(symbol->Name());
@@ -362,7 +363,7 @@ void TreeNode::WriteIntoJson(
 
   (*out)["size"] = size;
   (*out)["flags"] = flags;
-  node_stats.WriteIntoJson(&(*out)["childStats"]);
+  node_stats.WriteIntoJson(method_count_mode, &(*out)["childStats"]);
 
   const size_t kMaxChildNodesToExpand = 1000;
   if (children.size() > kMaxChildNodesToExpand) {
@@ -380,7 +381,7 @@ void TreeNode::WriteIntoJson(
     std::sort(children.begin(), children.end(), compare_func);
     for (unsigned int i = 0; i < children.size(); i++) {
       children[i]->WriteIntoJson(depth - 1, compare_func, is_sparse,
-                                 &(*out)["children"][i]);
+                                 method_count_mode, &(*out)["children"][i]);
     }
   }
 }
@@ -407,17 +408,24 @@ NodeStats::NodeStats(const BaseSymbol& symbol) {
   }
 }
 
-void NodeStats::WriteIntoJson(Json::Value* out) const {
+void NodeStats::WriteIntoJson(bool method_count_mode, Json::Value* out) const {
   (*out) = Json::Value(Json::objectValue);
   for (const auto kv : child_stats) {
     const std::string sectionId = std::string(1, static_cast<char>(kv.first));
     const Stat stats = kv.second;
     (*out)[sectionId] = Json::Value(Json::objectValue);
     (*out)[sectionId]["size"] = stats.size;
-    (*out)[sectionId]["count"] = stats.count;
     (*out)[sectionId]["added"] = stats.added;
     (*out)[sectionId]["removed"] = stats.removed;
     (*out)[sectionId]["changed"] = stats.changed;
+    // Count is used to store value for "method count" mode.
+    // Why? Because that's how it was implemented in the .ndjson worker.
+    int count = stats.count;
+    bool is_diff = stats.added > 0 || stats.removed > 0 || stats.changed > 0;
+    if (method_count_mode && is_diff) {
+      count = stats.added - stats.removed;
+    }
+    (*out)[sectionId]["count"] = count;
   }
 }
 

tools/binary_size/libsupersize/caspian/model.h

@@ -321,7 +321,7 @@ struct NodeStats {
   NodeStats();
   ~NodeStats();
   explicit NodeStats(const BaseSymbol& symbol);
-  void WriteIntoJson(Json::Value* out) const;
+  void WriteIntoJson(bool method_count_mode, Json::Value* out) const;
   NodeStats& operator+=(const NodeStats& other);
   SectionId ComputeBiggestSection() const;
   int32_t SumCount() const;
@@ -341,6 +341,7 @@ struct TreeNode {
   void WriteIntoJson(int depth,
                      CompareFunc compare_func,
                      bool is_sparse,
+                     bool method_count_mode,
                      Json::Value* out);
 
   GroupedPath id_path;

tools/binary_size/libsupersize/caspian/tree_builder.cc

@@ -130,7 +130,8 @@ Json::Value TreeBuilder::Open(const char* path) {
     exit(1);
   }
   Json::Value v;
-  node->WriteIntoJson(1, node_sort_func, size_info_->IsSparse(), &v);
+  node->WriteIntoJson(1, node_sort_func, size_info_->IsSparse(),
+                      method_count_mode_, &v);
   return v;
 }