From 433bb5e46ab0b7803fb2421bd50057738de1d45a Mon Sep 17 00:00:00 2001
From: Marcus Holland-Moritz <github@mhxnet.de>
Date: Sat, 27 Jul 2024 15:50:50 +0200
Subject: [PATCH] refactor: switch from folly::gen to ranges

---
 src/dwarfs/block_compressor.cpp           | 13 ++++++++-----
 src/dwarfs/internal/global_entry_data.cpp | 22 ++++++++++++++--------
 src/mkdwarfs_main.cpp                     |  6 +++---
 3 files changed, 25 insertions(+), 16 deletions(-)

diff --git a/src/dwarfs/block_compressor.cpp b/src/dwarfs/block_compressor.cpp
index 20c31e8d..161fb74a 100644
--- a/src/dwarfs/block_compressor.cpp
+++ b/src/dwarfs/block_compressor.cpp
@@ -23,8 +23,7 @@
 #include <cassert>
 #include <cstdint>
 #include <iostream>
-
-#include <folly/gen/Base.h>
+#include <ranges>
 
 #include <dwarfs/block_compressor.h>
 #include <dwarfs/error.h>
@@ -104,10 +103,14 @@ compression_registry::make_decompressor(compression_type type,
 void compression_registry::for_each_algorithm(
     std::function<void(compression_type, compression_info const&)> const& fn)
     const {
-  using namespace folly::gen;
+  auto view = std::views::keys(factories_);
+  std::vector<compression_type> types{view.begin(), view.end()};
 
-  from(factories_) | get<0>() | order |
-      [this, &fn](compression_type type) { fn(type, *factories_.at(type)); };
+  std::ranges::sort(types);
+
+  for (auto type : types) {
+    fn(type, *factories_.at(type));
+  }
 }
 
 compression_registry::compression_registry() = default;
diff --git a/src/dwarfs/internal/global_entry_data.cpp b/src/dwarfs/internal/global_entry_data.cpp
index 8b070d5f..cacfc078 100644
--- a/src/dwarfs/internal/global_entry_data.cpp
+++ b/src/dwarfs/internal/global_entry_data.cpp
@@ -19,7 +19,7 @@
  * along with dwarfs.  If not, see <https://www.gnu.org/licenses/>.
  */
 
-#include <folly/gen/Base.h>
+#include <ranges>
 
 #include <dwarfs/error.h>
 #include <dwarfs/internal/global_entry_data.h>
@@ -29,10 +29,12 @@ namespace dwarfs::internal {
 
 template <typename T, typename U>
 std::vector<T> global_entry_data::get_vector(map_type<T, U> const& map) const {
-  using namespace folly::gen;
-  std::vector<std::pair<T, U>> pairs(map.begin(), map.end());
-  return from(pairs) | orderBy([](auto const& p) { return p.second; }) |
-         get<0>() | as<std::vector>();
+  std::vector<std::pair<T, U>> pairs{map.begin(), map.end()};
+  std::ranges::sort(pairs, [](auto const& p1, auto const& p2) {
+    return p1.second < p2.second;
+  });
+  auto view = std::views::keys(pairs);
+  return std::vector<T>{view.begin(), view.end()};
 }
 
 auto global_entry_data::get_uids() const -> std::vector<uid_type> {
@@ -58,9 +60,13 @@ auto global_entry_data::get_symlinks() const -> std::vector<std::string> {
 }
 
 void global_entry_data::index(map_type<std::string, uint32_t>& map) {
-  using namespace folly::gen;
-  uint32_t ix = 0;
-  from(map) | get<0>() | order | [&](std::string const& s) { map[s] = ix++; };
+  auto keys = std::views::all(map) | std::views::keys;
+  std::vector<std::string_view> tmp{keys.begin(), keys.end()};
+  std::ranges::sort(tmp);
+  std::decay_t<decltype(map)>::mapped_type ix{0};
+  for (auto& s : tmp) {
+    map[s] = ix++;
+  }
 }
 
 uint64_t global_entry_data::get_time_offset(uint64_t time) const {
diff --git a/src/mkdwarfs_main.cpp b/src/mkdwarfs_main.cpp
index 222c9a01..ff04b428 100644
--- a/src/mkdwarfs_main.cpp
+++ b/src/mkdwarfs_main.cpp
@@ -410,15 +410,15 @@ int mkdwarfs_main(int argc, sys_char** argv, iolayer const& iol) {
   auto order_desc = "inode fragments order (" + order_parser.choices() + ")";
 
   auto progress_desc = fmt::format(
-      "progress mode ({})", fmt::join(progress_modes | std::views::keys, ", "));
+      "progress mode ({})", fmt::join(std::views::keys(progress_modes), ", "));
 
   auto debug_filter_desc =
       fmt::format("show effect of filter rules without producing an image ({})",
-                  fmt::join(debug_filter_modes | std::views::keys, ", "));
+                  fmt::join(std::views::keys(debug_filter_modes), ", "));
 
   auto resolution_desc =
       fmt::format("time resolution in seconds or ({})",
-                  fmt::join(time_resolutions | std::views::keys, ", "));
+                  fmt::join(std::views::keys(time_resolutions), ", "));
 
   auto hash_list = checksum::available_algorithms();