From e44519b75bb26ea02c00c7f67b2193ebc9f22ac9 Mon Sep 17 00:00:00 2001
From: Marcus Holland-Moritz <github@mhxnet.de>
Date: Sun, 22 Nov 2020 14:11:38 +0100
Subject: [PATCH] folly::StringPiece -> std::string_view

---
 include/dwarfs/entry.h           |  5 ++--
 include/dwarfs/hash_util.h       | 40 ++++++++++++++++++++++++++++++++
 include/dwarfs/metadata_writer.h |  5 ++--
 src/dwarfs/entry.cpp             |  4 ++--
 src/dwarfs/scanner.cpp           | 16 ++++++-------
 5 files changed, 54 insertions(+), 16 deletions(-)
 create mode 100644 include/dwarfs/hash_util.h

diff --git a/include/dwarfs/entry.h b/include/dwarfs/entry.h
index 7dc63eeb..fa9245e4 100644
--- a/include/dwarfs/entry.h
+++ b/include/dwarfs/entry.h
@@ -24,12 +24,11 @@
 #include <array>
 #include <functional>
 #include <memory>
+#include <string_view>
 #include <vector>
 
 #include <sys/stat.h>
 
-#include <folly/Range.h>
-
 #include "file_interface.h"
 #include "fstypes.h"
 
@@ -95,7 +94,7 @@ class file : public entry {
       , with_similarity_(with_similarity) {}
 
   type_t type() const override;
-  folly::StringPiece hash() const;
+  std::string_view hash() const;
   void set_inode(std::shared_ptr<inode> ino);
   std::shared_ptr<inode> get_inode() const;
   void accept(entry_visitor& v, bool preorder) override;
diff --git a/include/dwarfs/hash_util.h b/include/dwarfs/hash_util.h
new file mode 100644
index 00000000..cabdbe4f
--- /dev/null
+++ b/include/dwarfs/hash_util.h
@@ -0,0 +1,40 @@
+/* vim:set ts=2 sw=2 sts=2 et: */
+/**
+ * \author     Marcus Holland-Moritz (github@mhxnet.de)
+ * \copyright  Copyright (c) Marcus Holland-Moritz
+ *
+ * This file is part of dwarfs.
+ *
+ * dwarfs is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * dwarfs is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with dwarfs.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include <string_view>
+
+#include <folly/Hash.h>
+
+namespace folly {
+
+template <>
+struct hasher<std::string_view> {
+  using folly_is_avalanching = std::true_type;
+
+  size_t operator()(std::string_view r) const {
+    return static_cast<size_t>(
+        hash::SpookyHashV2::Hash64(r.data(), r.size(), 0));
+  }
+};
+
+}
diff --git a/include/dwarfs/metadata_writer.h b/include/dwarfs/metadata_writer.h
index bc6f08ee..a694718b 100644
--- a/include/dwarfs/metadata_writer.h
+++ b/include/dwarfs/metadata_writer.h
@@ -21,10 +21,9 @@
 
 #pragma once
 
+#include <string_view>
 #include <vector>
 
-#include <folly/Range.h>
-
 #include "fstypes.h"
 #include "logger.h"
 
@@ -82,7 +81,7 @@ class metadata_writer {
     }
   }
 
-  void write(folly::StringPiece str) {
+  void write(std::string_view str) {
     if (!str.empty()) {
       write(str.data(), str.size());
     }
diff --git a/src/dwarfs/entry.cpp b/src/dwarfs/entry.cpp
index 3500c0ed..303be74a 100644
--- a/src/dwarfs/entry.cpp
+++ b/src/dwarfs/entry.cpp
@@ -158,8 +158,8 @@ void entry::pack(dir_entry_ug_time& de) const {
 
 entry::type_t file::type() const { return E_FILE; }
 
-folly::StringPiece file::hash() const {
-  return folly::StringPiece(hash_.begin(), hash_.end());
+std::string_view file::hash() const {
+  return std::string_view(&hash_[0], hash_.size());
 }
 
 void file::set_inode(std::shared_ptr<inode> ino) {
diff --git a/src/dwarfs/scanner.cpp b/src/dwarfs/scanner.cpp
index d15e3a52..b1a7e7a9 100644
--- a/src/dwarfs/scanner.cpp
+++ b/src/dwarfs/scanner.cpp
@@ -34,7 +34,6 @@
 #include <boost/system/system_error.hpp>
 
 #include <folly/Conv.h>
-#include <folly/Range.h>
 #include <folly/String.h>
 #include <folly/small_vector.h>
 
@@ -46,6 +45,7 @@
 #include "dwarfs/entry.h"
 #include "dwarfs/filesystem_writer.h"
 #include "dwarfs/fstypes.h"
+#include "dwarfs/hash_util.h"
 #include "dwarfs/inode_manager.h"
 #include "dwarfs/logger.h"
 #include "dwarfs/metadata.h"
@@ -85,9 +85,9 @@ class scanner_ : public scanner::impl {
   // TODO: StringPiece?
   // TODO: Use dense/unordered maps/sets and sort later?
   using file_name_table_t =
-      fast_hash_map<size_t, fast_hash_set<folly::StringPiece, folly::Hash>>;
+      fast_hash_map<size_t, fast_hash_set<std::string_view, folly::Hash>>;
 
-  std::unordered_map<folly::StringPiece, size_t, folly::Hash>
+  std::unordered_map<std::string_view, size_t, folly::Hash>
   compress_names_table(metadata_writer& mw,
                        const file_name_table_t& file_name) const;
 
@@ -118,7 +118,7 @@ scanner_<LoggerPolicy>::scanner_(logger& lgr, worker_group& wg,
     , log_(lgr) {}
 
 template <typename LoggerPolicy>
-std::unordered_map<folly::StringPiece, size_t, folly::Hash>
+std::unordered_map<std::string_view, size_t, folly::Hash>
 scanner_<LoggerPolicy>::compress_names_table(
     metadata_writer& mw, const file_name_table_t& file_name) const {
   log_.info() << "compressing names table...";
@@ -130,7 +130,7 @@ scanner_<LoggerPolicy>::compress_names_table(
   index.set_empty_key(0);
   uint32_t index_pos = 0;
 
-  std::unordered_map<folly::StringPiece, size_t, folly::Hash> offset;
+  std::unordered_map<std::string_view, size_t, folly::Hash> offset;
   size_t saved = 0;
   size_t orig_offset = mw.offset();
 
@@ -142,7 +142,7 @@ scanner_<LoggerPolicy>::compress_names_table(
   for (auto size : sizes) {
     auto nsi = file_name.find(size);
     assert(nsi != file_name.end());
-    std::vector<folly::StringPiece> names(nsi->second.size());
+    std::vector<std::string_view> names(nsi->second.size());
     std::copy(nsi->second.begin(), nsi->second.end(), names.begin());
     std::sort(names.begin(), names.end());
 
@@ -250,7 +250,7 @@ class save_links_visitor : public entry_visitor {
 
  private:
   metadata_writer& mw_;
-  std::unordered_map<folly::StringPiece, size_t, folly::Hash> offset_;
+  std::unordered_map<std::string_view, size_t, folly::Hash> offset_;
 };
 
 class save_directories_visitor : public entry_visitor {
@@ -374,7 +374,7 @@ void scanner_<LoggerPolicy>::scan(filesystem_writer& fsw,
   wg_.wait();
 
   size_t total{0};
-  std::unordered_map<folly::StringPiece, std::vector<file*>, folly::Hash>
+  std::unordered_map<std::string_view, std::vector<file*>, folly::Hash>
       file_hash;
   file_name_table_t file_name;