From 69f30a350575b4aa0267f3f8f222e3dcc63c698e Mon Sep 17 00:00:00 2001
From: levlam <levlam@telegram.org>
Date: Fri, 3 Jan 2020 01:01:39 +0300
Subject: [PATCH] Add real_size to Stat.

GitOrigin-RevId: 3b8b4c24504ed1fa7eed1885abd3a3e9014eb2c4
---
 tdutils/td/utils/port/FileFd.cpp | 10 ++++++++++
 tdutils/td/utils/port/FileFd.h   |  4 ++++
 tdutils/td/utils/port/Stat.cpp   |  1 +
 tdutils/td/utils/port/Stat.h     |  1 +
 tdutils/test/port.cpp            | 16 ++++++++++++++++
 5 files changed, 32 insertions(+)

diff --git a/tdutils/td/utils/port/FileFd.cpp b/tdutils/td/utils/port/FileFd.cpp
index fc4096af..2f65df61 100644
--- a/tdutils/td/utils/port/FileFd.cpp
+++ b/tdutils/td/utils/port/FileFd.cpp
@@ -480,6 +480,11 @@ Result<int64> FileFd::get_size() const {
   return s.size_;
 }
 
+Result<int64> FileFd::get_real_size() const {
+  TRY_RESULT(s, stat());
+  return s.real_size_;
+}
+
 #if TD_PORT_WINDOWS
 static uint64 filetime_to_unix_time_nsec(LONGLONG filetime) {
   const auto FILETIME_UNIX_TIME_DIFF = 116444736000000000ll;
@@ -510,6 +515,11 @@ Result<Stat> FileFd::stat() const {
     return OS_ERROR("Get FileStandardInfo failed");
   }
   res.size_ = standard_info.EndOfFile.QuadPart;
+  res.real_size_ = standard_info.AllocationSize.QuadPart;
+
+  if (res.size_ != 0 && res.real_size_ <= 0 ) {
+    res.real_size_ = res.size_; // just in case
+  }
 
   return res;
 #endif
diff --git a/tdutils/td/utils/port/FileFd.h b/tdutils/td/utils/port/FileFd.h
index f70a6dfe..2751af84 100644
--- a/tdutils/td/utils/port/FileFd.h
+++ b/tdutils/td/utils/port/FileFd.h
@@ -50,11 +50,15 @@ class FileFd {
 
   PollableFdInfo &get_poll_info();
   const PollableFdInfo &get_poll_info() const;
+
   void close();
+
   bool empty() const;
 
   Result<int64> get_size() const;
 
+  Result<int64> get_real_size() const;
+
   Result<Stat> stat() const;
 
   Status sync() TD_WARN_UNUSED_RESULT;
diff --git a/tdutils/td/utils/port/Stat.cpp b/tdutils/td/utils/port/Stat.cpp
index baccc9e5..ff1e20d9 100644
--- a/tdutils/td/utils/port/Stat.cpp
+++ b/tdutils/td/utils/port/Stat.cpp
@@ -106,6 +106,7 @@ Stat from_native_stat(const struct ::stat &buf) {
   res.atime_nsec_ = static_cast<uint64>(buf.st_atime) * 1000000000 + time_nsec.first;
   res.mtime_nsec_ = static_cast<uint64>(buf.st_mtime) * 1000000000 + time_nsec.second / 1000 * 1000;
   res.size_ = buf.st_size;
+  res.real_size_ = buf.st_blocks * 512;
   res.is_dir_ = (buf.st_mode & S_IFMT) == S_IFDIR;
   res.is_reg_ = (buf.st_mode & S_IFMT) == S_IFREG;
   return res;
diff --git a/tdutils/td/utils/port/Stat.h b/tdutils/td/utils/port/Stat.h
index 48463b30..1e0fc297 100644
--- a/tdutils/td/utils/port/Stat.h
+++ b/tdutils/td/utils/port/Stat.h
@@ -18,6 +18,7 @@ struct Stat {
   bool is_dir_;
   bool is_reg_;
   int64 size_;
+  int64 real_size_;
   uint64 atime_nsec_;
   uint64 mtime_nsec_;
 };
diff --git a/tdutils/test/port.cpp b/tdutils/test/port.cpp
index 3dba488e..5a16dc3d 100644
--- a/tdutils/test/port.cpp
+++ b/tdutils/test/port.cpp
@@ -95,6 +95,22 @@ TEST(Port, files) {
   ASSERT_STREQ("Habcd world?!", buf_slice.substr(0, 13));
 }
 
+TEST(Port, SparseFiles) {
+  CSlice path = "sparse.txt";
+  unlink(path).ignore();
+  auto fd = FileFd::open(path, FileFd::Write | FileFd::CreateNew).move_as_ok();
+  ASSERT_EQ(0, fd.get_size().move_as_ok());
+  ASSERT_EQ(0, fd.get_real_size().move_as_ok());
+  int64 offset = 100000000;
+  fd.pwrite("a", offset);
+  ASSERT_EQ(offset + 1, fd.get_size().move_as_ok());
+  auto real_size = fd.get_real_size().move_as_ok();
+  if (real_size == offset + 1) {
+    LOG(ERROR) << "File system doesn't support sparse files, rewind during streaming can be slow";
+  }
+  unlink(path).ensure();
+}
+
 TEST(Port, Writev) {
   std::vector<IoSlice> vec;
   CSlice test_file_path = "test.txt";