extents() now returns an extent_pair, as per LEWG-I guidance.

6 files changed, 26 insertions, 12 deletions

diff --git a/example/use_cases.cpp b/example/use_cases.cpp
index ac632333..62ab7d23 100644
--- a/example/use_cases.cpp
+++ b/example/use_cases.cpp
@@ -86,7 +86,7 @@ void read_entire_file2()
 
   // Get the valid extents of the file.
   const std::vector<
-    std::pair<llfio::file_handle::extent_type, llfio::file_handle::extent_type>
+    llfio::file_handle::extent_pair
   > valid_extents = fh.extents().value();
 
   // Schedule asynchronous reads for every valid extent
@@ -94,13 +94,13 @@ void read_entire_file2()
   for (size_t n = 0; n < valid_extents.size(); n++)
   {
     // Set up the scatter buffer
-    buffers[n].first.resize(valid_extents[n].second);
+    buffers[n].first.resize(valid_extents[n].length);
     for(;;)
     {
       llfio::async_file_handle::buffer_type scatter_req{ buffers[n].first.data(), buffers[n].first.size() };  // buffer to fill
       auto ret = llfio::async_read( //
         fh,                                           // handle to read from
-        { { scatter_req }, valid_extents[n].first },  // The scatter request buffers + offset
+        { { scatter_req }, valid_extents[n].offset },  // The scatter request buffers + offset
         [](                                                                               // The completion handler
           llfio::async_file_handle *,                                                     // The parent handle
           llfio::async_file_handle::io_result<llfio::async_file_handle::buffers_type> &&  // Result of the i/o
diff --git a/include/llfio/v2.0/algorithm/handle_adapter/combining.hpp b/include/llfio/v2.0/algorithm/handle_adapter/combining.hpp
index 73b935ec..6f18ffc1 100644
--- a/include/llfio/v2.0/algorithm/handle_adapter/combining.hpp
+++ b/include/llfio/v2.0/algorithm/handle_adapter/combining.hpp
@@ -434,7 +434,7 @@ namespace algorithm
         return ret;
       }
       //! \brief Always returns a failed matching `errc::operation_not_supported` as the meaning of combined valid extents is hard to discern here.
-      LLFIO_HEADERS_ONLY_VIRTUAL_SPEC result<std::vector<std::pair<extent_type, extent_type>>> extents() const noexcept override { return errc::operation_not_supported; }
+      LLFIO_HEADERS_ONLY_VIRTUAL_SPEC result<std::vector<file_handle::extent_pair>> extents() const noexcept override { return errc::operation_not_supported; }
       //! \brief Punches a hole in one or both attached handles. Note that no combination operation is performed.
       LLFIO_HEADERS_ONLY_VIRTUAL_SPEC result<extent_type> zero(extent_type offset, extent_type bytes, deadline d = deadline()) noexcept override
       {
diff --git a/include/llfio/v2.0/detail/impl/posix/file_handle.ipp b/include/llfio/v2.0/detail/impl/posix/file_handle.ipp
index 2246a627..070fef1c 100644
--- a/include/llfio/v2.0/detail/impl/posix/file_handle.ipp
+++ b/include/llfio/v2.0/detail/impl/posix/file_handle.ipp
@@ -330,12 +330,12 @@ result<file_handle::extent_type> file_handle::truncate(file_handle::extent_type
   return newsize;
 }
 
-result<std::vector<std::pair<file_handle::extent_type, file_handle::extent_type>>> file_handle::extents() const noexcept
+result<std::vector<file_handle::extent_pair>> file_handle::extents() const noexcept
 {
   LLFIO_LOG_FUNCTION_CALL(this);
   try
   {
-    std::vector<std::pair<file_handle::extent_type, file_handle::extent_type>> out;
+    std::vector<file_handle::extent_pair> out;
     out.reserve(64);
     extent_type start = 0, end = 0;
     for(;;)
diff --git a/include/llfio/v2.0/detail/impl/windows/file_handle.ipp b/include/llfio/v2.0/detail/impl/windows/file_handle.ipp
index e646fcd0..ad6b0138 100644
--- a/include/llfio/v2.0/detail/impl/windows/file_handle.ipp
+++ b/include/llfio/v2.0/detail/impl/windows/file_handle.ipp
@@ -338,15 +338,15 @@ result<file_handle::extent_type> file_handle::truncate(file_handle::extent_type
   return newsize;
 }
 
-result<std::vector<std::pair<file_handle::extent_type, file_handle::extent_type>>> file_handle::extents() const noexcept
+result<std::vector<file_handle::extent_pair>> file_handle::extents() const noexcept
 {
   windows_nt_kernel::init();
   using namespace windows_nt_kernel;
   LLFIO_LOG_FUNCTION_CALL(this);
   try
   {
-    static_assert(sizeof(std::pair<file_handle::extent_type, file_handle::extent_type>) == sizeof(FILE_ALLOCATED_RANGE_BUFFER), "FILE_ALLOCATED_RANGE_BUFFER is not equivalent to pair<extent_type, extent_type>!");
-    std::vector<std::pair<file_handle::extent_type, file_handle::extent_type>> ret;
+    static_assert(sizeof(file_handle::extent_pair) == sizeof(FILE_ALLOCATED_RANGE_BUFFER), "FILE_ALLOCATED_RANGE_BUFFER is not equivalent to pair<extent_type, extent_type>!");
+    std::vector<file_handle::extent_pair> ret;
 #ifdef NDEBUG
     ret.resize(64);
 #else
diff --git a/include/llfio/v2.0/fast_random_file_handle.hpp b/include/llfio/v2.0/fast_random_file_handle.hpp
index 2e214255..e1c2049b 100644
--- a/include/llfio/v2.0/fast_random_file_handle.hpp
+++ b/include/llfio/v2.0/fast_random_file_handle.hpp
@@ -225,7 +225,7 @@ public:
   }
 
   //! \brief Return a single extent of the maximum extent
-  LLFIO_HEADERS_ONLY_VIRTUAL_SPEC result<std::vector<std::pair<extent_type, extent_type>>> extents() const noexcept override { return std::vector<std::pair<extent_type, extent_type>>{{0, _length}}; }
+  LLFIO_HEADERS_ONLY_VIRTUAL_SPEC result<std::vector<file_handle::extent_pair>> extents() const noexcept override { return std::vector<file_handle::extent_pair>{{0, _length}}; }
 
 
   using file_handle::read;
diff --git a/include/llfio/v2.0/file_handle.hpp b/include/llfio/v2.0/file_handle.hpp
index 747fdf8a..6e37741b 100644
--- a/include/llfio/v2.0/file_handle.hpp
+++ b/include/llfio/v2.0/file_handle.hpp
@@ -291,13 +291,27 @@ public:
   LLFIO_MAKE_FREE_FUNCTION
   LLFIO_HEADERS_ONLY_VIRTUAL_SPEC result<extent_type> truncate(extent_type newsize) noexcept;
 
+  //! \brief A pair of valid extents
+  struct extent_pair
+  {
+    extent_type offset{(extent_type) -1};  //!< The offset of where the valid extent begins
+    extent_type length{(extent_type) -1};  //!< The number of valid bytes in the valid extent
+
+    constexpr extent_pair() {}
+    constexpr extent_pair(extent_type _offset, extent_type _length)
+        : offset(_offset)
+        , length(_length)
+    {
+    }
+  };
+
   /*! \brief Returns a list of currently valid extents for this open file. WARNING: racy!
   \return A vector of pairs of extent offset + extent length representing the valid extents
   in this file. Filing systems which do not support extents return a single extent matching
   the length of the file rather than returning an error.
   */
   LLFIO_MAKE_FREE_FUNCTION
-  LLFIO_HEADERS_ONLY_VIRTUAL_SPEC result<std::vector<std::pair<extent_type, extent_type>>> extents() const noexcept;
+  LLFIO_HEADERS_ONLY_VIRTUAL_SPEC result<std::vector<extent_pair>> extents() const noexcept;
 
   /*! \brief Efficiently zero, and possibly deallocate, data on storage.
 
@@ -432,7 +446,7 @@ inline result<file_handle::extent_type> truncate(file_handle &self, file_handle:
 }
 /*! \brief Returns a list of currently valid extents for this open file. WARNING: racy!
  */
-inline result<std::vector<std::pair<file_handle::extent_type, file_handle::extent_type>>> extents(const file_handle &self) noexcept
+inline result<std::vector<file_handle::extent_pair>> extents(const file_handle &self) noexcept
 {
   return self.extents();
 }