Now fully working on POSIX

7 files changed, 97 insertions, 45 deletions

diff --git a/doc/html b/doc/html
-Subproject 29c456437d320dbe7ddbc33e491984af0b14583
+Subproject 1d80781cac7cb087435fb798c636896045b2daa
diff --git a/include/afio/revision.hpp b/include/afio/revision.hpp
index a6b8436c..7be09270 100644
--- a/include/afio/revision.hpp
+++ b/include/afio/revision.hpp
@@ -1,4 +1,4 @@
 // Note the second line of this file must ALWAYS be the git SHA, third line ALWAYS the git SHA update time
-#define AFIO_PREVIOUS_COMMIT_REF    afa177fe7e944a5adc015d5237a5bed2c9cc5e2e
-#define AFIO_PREVIOUS_COMMIT_DATE   "2017-09-10 00:09:57 +00:00"
-#define AFIO_PREVIOUS_COMMIT_UNIQUE afa177fe
+#define AFIO_PREVIOUS_COMMIT_REF    3afebec0fd8750ff8a83eebc4f8de0480dd67e09
+#define AFIO_PREVIOUS_COMMIT_DATE   "2017-09-10 01:53:53 +00:00"
+#define AFIO_PREVIOUS_COMMIT_UNIQUE 3afebec0
diff --git a/include/afio/v2.0/detail/impl/posix/map_handle.ipp b/include/afio/v2.0/detail/impl/posix/map_handle.ipp
index 72927cd6..1032421d 100644
--- a/include/afio/v2.0/detail/impl/posix/map_handle.ipp
+++ b/include/afio/v2.0/detail/impl/posix/map_handle.ipp
@@ -29,39 +29,60 @@ Distributed under the Boost Software License, Version 1.0.
 
 AFIO_V2_NAMESPACE_BEGIN
 
-result<section_handle> section_handle::section(file_handle &backing, extent_type maximum_size, flag _flag) noexcept
+section_handle::~section_handle()
 {
-  extent_type length = 0;
-  if(backing.is_valid())
+  if(_v)
   {
-    OUTCOME_TRY(_length, backing.length());
-    length = _length;
-    if(length == 0)
-    {
-      // Some systems allow zero sized maps, POSIX bans it
-      return std::errc::invalid_argument;
-    }
-    if(maximum_size > 0 && maximum_size > length)
-    {
-      // For compatibility with Windows, disallow sections larger than the file
-      return std::errc::value_too_large;
-    }
+    (void) section_handle::close();
   }
-  if(!maximum_size)
+}
+result<void> section_handle::close() noexcept
+{
+  AFIO_LOG_FUNCTION_CALL(this);
+  // We don't want ~handle() to close our fake handle
+  _v = native_handle_type();
+  return success();
+}
+
+result<section_handle> section_handle::section(file_handle &backing, extent_type maximum_size, flag _flag) noexcept
+{
+  if(!(_flag & flag::posix_skip_length_checks))
   {
+    extent_type length = 0;
     if(backing.is_valid())
     {
-      maximum_size = length;
+      OUTCOME_TRY(_length, backing.length());
+      length = _length;
+      if(length == 0)
+      {
+        // Some systems allow zero sized maps, POSIX bans it
+        return std::errc::invalid_argument;
+      }
+      if(maximum_size > 0 && maximum_size > length)
+      {
+        // For compatibility with Windows, disallow sections larger than the file
+        return std::errc::value_too_large;
+      }
     }
-    else
+    if(!maximum_size)
     {
-      return std::errc::invalid_argument;
+      if(backing.is_valid())
+      {
+        maximum_size = length;
+      }
+      else
+      {
+        return std::errc::invalid_argument;
+      }
     }
   }
   if(!backing.is_valid())
     maximum_size = utils::round_up_to_page_size(maximum_size);
   result<section_handle> ret(section_handle(native_handle_type(), backing.is_valid() ? &backing : nullptr, maximum_size, _flag));
   // There are no section handles on POSIX, so do nothing
+  native_handle_type &nativeh = ret.value()._v;
+  nativeh.fd = INT_MAX;
+  nativeh.behaviour |= native_handle_type::disposition::section;
   AFIO_LOG_FUNCTION_CALL(&ret);
   return ret;
 }
@@ -75,20 +96,23 @@ result<section_handle::extent_type> section_handle::length() const noexcept
 result<section_handle::extent_type> section_handle::truncate(extent_type newsize) noexcept
 {
   AFIO_LOG_FUNCTION_CALL(this);
-  extent_type length = 0;
   if(_backing)
   {
-    OUTCOME_TRY(_length, _backing->length());
-    length = _length;
-    if(length == 0)
+    extent_type length = 0;
+    if(!(_flag & flag::posix_skip_length_checks))
     {
-      // Some systems allow zero sized maps, POSIX bans it
-      return std::errc::invalid_argument;
-    }
-    if(newsize > 0 && newsize > length)
-    {
-      // For compatibility with Windows, disallow sections larger than the file
-      return std::errc::value_too_large;
+      OUTCOME_TRY(_length, _backing->length());
+      length = _length;
+      if(length == 0)
+      {
+        // Some systems allow zero sized maps, POSIX bans it
+        return std::errc::invalid_argument;
+      }
+      if(newsize > 0 && newsize > length)
+      {
+        // For compatibility with Windows, disallow sections larger than the file
+        return std::errc::value_too_large;
+      }
     }
   }
   else
diff --git a/include/afio/v2.0/detail/impl/posix/mapped_file_handle.ipp b/include/afio/v2.0/detail/impl/posix/mapped_file_handle.ipp
index eff0ef77..0eac991e 100644
--- a/include/afio/v2.0/detail/impl/posix/mapped_file_handle.ipp
+++ b/include/afio/v2.0/detail/impl/posix/mapped_file_handle.ipp
@@ -30,16 +30,20 @@ AFIO_V2_NAMESPACE_BEGIN
 result<mapped_file_handle::size_type> mapped_file_handle::reserve(size_type reservation) noexcept
 {
   AFIO_LOG_FUNCTION_CALL(this);
+  OUTCOME_TRY(length, underlying_file_length());
+  if(length == 0)
+  {
+    return std::errc::invalid_argument;
+  }
   if(reservation == 0)
   {
-    OUTCOME_TRY(length, underlying_file_length());
     reservation = length;
   }
   reservation = utils::round_up_to_page_size(reservation);
   if(!_sh.is_valid())
   {
-    section_handle::flag sectionflags = section_handle::flag::readwrite;
-    OUTCOME_TRY(sh, section_handle::section(*this, 0, sectionflags));
+    section_handle::flag sectionflags = section_handle::flag::readwrite | section_handle::flag::posix_skip_length_checks;
+    OUTCOME_TRY(sh, section_handle::section(*this, length, sectionflags));
     _sh = std::move(sh);
   }
   if(_mh.is_valid() && reservation == _mh.length())
diff --git a/include/afio/v2.0/map_handle.hpp b/include/afio/v2.0/map_handle.hpp
index 1d25974e..e2f44685 100644
--- a/include/afio/v2.0/map_handle.hpp
+++ b/include/afio/v2.0/map_handle.hpp
@@ -63,6 +63,8 @@ public:
                                    barrier_on_close = 1 << 16,  //!< Maps of this section, if writable, issue a `barrier()` when destructed blocking until data (not metadata) reaches physical storage.
 
                                    // NOTE: IF UPDATING THIS UPDATE THE std::ostream PRINTER BELOW!!!
+                                   
+                                   posix_skip_length_checks = 1 << 28,
 
                                    readwrite = (read | write)};
   QUICKCPPLIB_BITFIELD_END(flag);
@@ -73,6 +75,10 @@ protected:
   flag _flag;
 
 public:
+#ifndef _WIN32
+  AFIO_HEADERS_ONLY_VIRTUAL_SPEC ~section_handle();
+  AFIO_HEADERS_ONLY_VIRTUAL_SPEC result<void> close() noexcept override;
+#endif
   //! Default constructor
   constexpr section_handle()
       : _backing(nullptr)
diff --git a/include/afio/v2.0/mapped_file_handle.hpp b/include/afio/v2.0/mapped_file_handle.hpp
index 64d79a44..ff1b8b5c 100644
--- a/include/afio/v2.0/mapped_file_handle.hpp
+++ b/include/afio/v2.0/mapped_file_handle.hpp
@@ -84,6 +84,7 @@ data, you can call `update_map()` which guarantees that the mapping your
 process sees is up to date, rather than relying on any kernel-specific automatic mapping.
 Whether automatic or enforced by `update_map()`, the reservation limit will not be exceeded
 nor will `address()` suddenly return something different.
+
 It is thus up to you to detect that the reservation has been exhausted, and to
 reserve a new reservation which will change the value returned by `address()`. This
 entirely manual system is a bit tedious and cumbersome to use, but as mapping files
@@ -100,9 +101,15 @@ Automatic mapping of growing files on various kernels:
 <dl>
 <dt>Microsoft Windows</dt>
 <dd>For the current Terminal Services Session, the first `mapped_file_handle::truncate()` or
-`mapped_file_handle::update_map()` by any process update maps in all processes simultaneously.</dd>
+`mapped_file_handle::update_map()` by any process update maps in all processes simultaneously.
+Other methods for extending the file will require a `mapped_file_handle::update_map()`
+by any process per Terminal Services Session to synchronise.
+</dd>
 <dt>Linux</dt>
-<dd>?</dd>
+<dd>The Linux kernel automatically maps newly appended data to a file into all over extended
+maps of that file. `mapped_file_handle::length()` will continue to return the old value until
+`mapped_file_handle::update_map()` is called to refresh it.
+</dd>
 <dt>FreeBSD</dt>
 <dd>?</dd>
 <dt>Apple MacOS</dt>
@@ -115,7 +122,13 @@ Automatic mapping of shrinking files on various kernels:
 <dd>All maps and open section handles on the file anywhere in the system must be removed before
 any shrinkage of a file is permitted.</dd>
 <dt>Linux</dt>
-<dd>?</dd>
+<dd>Data written after the maximum extent up to the page boundary appears to be zeroed on flush
+and any pages thereafter appear to be unmapped. Just to be safe, on all POSIX platforms
+`mapped_file_handle::truncate()` specifically
+undirties any pages about to be freed on newer kernels, or specifically deallocates them from
+memory and physical storage on older kernels before doing the file shrink. This ensures
+truncated pages don't get zombified.
+</dd>
 <dt>FreeBSD</dt>
 <dd>?</dd>
 <dt>Apple MacOS</dt>
@@ -152,7 +165,7 @@ public:
   mapped_file_handle() = default;
 
   //! Implicit move construction of mapped_file_handle permitted
-  mapped_file_handle(mapped_file_handle &&o) noexcept : file_handle(std::move(o)), _sh(std::move(o._sh)), _mh(std::move(o._mh))
+  mapped_file_handle(mapped_file_handle &&o) noexcept : file_handle(std::move(o)), _reservation(std::move(o._reservation)), _sh(std::move(o._sh)), _mh(std::move(o._mh))
   {
     _sh.set_backing(this);
     _mh.set_section(&_sh);
diff --git a/test/tests/mapped_view.cpp b/test/tests/mapped_view.cpp
index f849d4ec..124a5865 100644
--- a/test/tests/mapped_view.cpp
+++ b/test/tests/mapped_view.cpp
@@ -65,6 +65,10 @@ static inline void TestMappedView2()
 {
   using namespace AFIO_V2_NAMESPACE;
   using AFIO_V2_NAMESPACE::file_handle;
+  {
+    std::error_code ec;
+    filesystem::remove("testfile", ec);
+  }
   mapped_file_handle mfh = mapped_file_handle::mapped_file(1024 * 1024, {}, "testfile", file_handle::mode::write, file_handle::creation::if_needed, file_handle::caching::all, file_handle::flag::unlink_on_close).value();
   BOOST_CHECK(mfh.address() == nullptr);
   mfh.truncate(10000 * sizeof(int)).value();
@@ -106,7 +110,8 @@ static inline void TestMappedView2()
   BOOST_CHECK(v1.size() == 10000);
   v1[0] = 78;
   v1[9999] = 79;
-  // Should have auto informed mfh of the change and remapped it for us
+  // On Windows this will have updated the mapping, on POSIX it will not, so prod POSIX
+  mfh.update_map().value();
   v1 = mfh;
   BOOST_CHECK(v1.size() == 10000);
   BOOST_CHECK(v1[0] == 78);