MinGW: implement mmap
Add USE_WIN32_MMAP which triggers the use of windows' native
file memory mapping functionality in git_mmap()/git_munmap() functions.
As git functions currently use mmap with MAP_PRIVATE set only, this
implementation supports only that mode for now.
On Windows, offsets for memory mapped files need to match the allocation
granularity. Take this into account when calculating the packed git-
windowsize and file offsets. At the moment, the only function which makes
use of offsets in conjunction with mmap is use_pack() in sha1-file.c.
Git fast-import's code path tries to map a portion of the temporary
packfile that exceeds the current filesize, i.e. offset+length is
greater than the filesize. The NO_MMAP code worked with that since pread()
just reads the file content until EOF and returns gracefully, while
MapViewOfFile() aborts the mapping and returns 'Access Denied'.
Working around that by determining the filesize and adjusting the length
parameter.
Signed-off-by: Janos Laube <janos.dev@gmail.com>
Signed-off-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/Makefile b/Makefile
index b96c2b3..aae3b09 100644
--- a/Makefile
+++ b/Makefile
@@ -784,7 +784,6 @@
COMPAT_OBJS += compat/cygwin.o
endif
ifneq (,$(findstring MINGW,$(uname_S)))
- NO_MMAP = YesPlease
NO_PREAD = YesPlease
NO_OPENSSL = YesPlease
NO_CURL = YesPlease
@@ -808,6 +807,7 @@
NO_POSIX_ONLY_PROGRAMS = YesPlease
NO_ST_BLOCKS_IN_STRUCT_STAT = YesPlease
NO_NSEC = YesPlease
+ USE_WIN32_MMAP = YesPlease
COMPAT_CFLAGS += -D__USE_MINGW_ACCESS -DNOGDI -Icompat -Icompat/regex -Icompat/fnmatch
COMPAT_CFLAGS += -DSNPRINTF_SIZE_CORR=1
COMPAT_CFLAGS += -DSTRIP_EXTENSION=\".exe\"
@@ -985,6 +985,11 @@
ifdef NO_MMAP
COMPAT_CFLAGS += -DNO_MMAP
COMPAT_OBJS += compat/mmap.o
+else
+ ifdef USE_WIN32_MMAP
+ COMPAT_CFLAGS += -DUSE_WIN32_MMAP
+ COMPAT_OBJS += compat/win32mmap.o
+ endif
endif
ifdef NO_PREAD
COMPAT_CFLAGS += -DNO_PREAD
