From e849fa158b16df9af0352c674d272ee43b4123a1 Mon Sep 17 00:00:00 2001
From: Marcus Holland-Moritz <github@mhxnet.de>
Date: Wed, 3 Mar 2021 13:17:05 +0100
Subject: [PATCH] Replace dense_hash_map with F14 maps

---
 CMakeLists.txt               |  5 +----
 README.md                    |  3 +--
 src/dwarfs/block_manager.cpp | 14 +++++---------
 src/dwarfs/python_script.cpp |  7 +++----
 4 files changed, 10 insertions(+), 19 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index c423f968..e480f4a9 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -102,8 +102,6 @@ if(NOT FUSE_FOUND AND NOT FUSE3_FOUND)
   message(FATAL_ERROR "No FUSE or FUSE3 library found")
 endif()
 
-find_path(SPARSEHASH_INCLUDE_DIR sparsehash/dense_hash_map
-          DOC "dense_hash_map header" REQUIRED)
 find_program(RONN_EXE ronn DOC "ronn man page generator" REQUIRED)
 
 if(USE_JEMALLOC)
@@ -358,8 +356,7 @@ list(
   ${CMAKE_CURRENT_SOURCE_DIR}/fbthrift
   ${CMAKE_CURRENT_SOURCE_DIR}/zstd/lib
   ${CMAKE_CURRENT_SOURCE_DIR}/xxHash
-  ${CMAKE_CURRENT_BINARY_DIR}
-  ${SPARSEHASH_INCLUDE_DIR})
+  ${CMAKE_CURRENT_BINARY_DIR})
 
 if(USE_JEMALLOC)
   list(APPEND INCLUDE_DIRS ${Jemalloc_INCLUDE_DIRS})
diff --git a/README.md b/README.md
index a97177fb..3a351420 100644
--- a/README.md
+++ b/README.md
@@ -158,8 +158,7 @@ A good starting point for apt-based systems is probably:
         libelf-dev \
         libfmt-dev \
         libfuse3-dev \
-        libgoogle-glog-dev \
-        libsparsehash-dev
+        libgoogle-glog-dev
 
 You can pick either `clang` or `g++`, but at least recent `clang`
 versions will produce substantially faster code:
diff --git a/src/dwarfs/block_manager.cpp b/src/dwarfs/block_manager.cpp
index 0aa567c4..6fb34973 100644
--- a/src/dwarfs/block_manager.cpp
+++ b/src/dwarfs/block_manager.cpp
@@ -31,8 +31,7 @@
 
 #include <fmt/format.h>
 
-#include <sparsehash/dense_hash_map>
-
+#include <folly/container/F14Map.h>
 #include <folly/small_vector.h>
 #include <folly/stats/Histogram.h>
 
@@ -87,19 +86,16 @@ struct bm_stats {
   folly::Histogram<size_t> l2_collision_vec_size;
 };
 
-template <typename KeyT, typename ValT, KeyT EmptyKey = KeyT{},
-          size_t MaxCollInline = 2>
+template <typename KeyT, typename ValT, size_t MaxCollInline = 2>
 class fast_multimap {
  private:
   using collision_vector = folly::small_vector<ValT, MaxCollInline>;
-  using blockhash_t = google::dense_hash_map<KeyT, ValT>;
-  using collision_t = std::unordered_map<KeyT, collision_vector>;
+  using blockhash_t = folly::F14ValueMap<KeyT, ValT>;
+  using collision_t = folly::F14FastMap<KeyT, collision_vector>;
 
  public:
-  fast_multimap() { values_.set_empty_key(EmptyKey); }
-
   void insert(KeyT const& key, ValT const& val) {
-    if (key == EmptyKey or !values_.insert(std::make_pair(key, val)).second) {
+    if (!values_.insert(std::make_pair(key, val)).second) {
       collisions_[key].emplace_back(val);
     }
   }
diff --git a/src/dwarfs/python_script.cpp b/src/dwarfs/python_script.cpp
index c747d644..4686087d 100644
--- a/src/dwarfs/python_script.cpp
+++ b/src/dwarfs/python_script.cpp
@@ -26,10 +26,10 @@
 #include <boost/algorithm/string.hpp>
 #include <boost/python.hpp>
 
-#include <sparsehash/dense_hash_map>
-
 #include <fmt/format.h>
 
+#include <folly/container/F14Map.h>
+
 #include "dwarfs/entry.h"
 #include "dwarfs/error.h"
 #include "dwarfs/inode.h"
@@ -396,8 +396,7 @@ void python_script::impl::order(inode_vector& iv) {
       td << "ordered files in script code";
     }
 
-    google::dense_hash_map<inode const*, size_t> priority(iv.size());
-    priority.set_empty_key(nullptr);
+    folly::F14FastMap<inode const*, size_t> priority(iv.size());
 
     auto td = LOG_TIMED_DEBUG;
     size_t index = 0;