upstream/mercurial-mirror Files · mercurial/cffi/mpatchbuild.py

revlog: add the option to track the expected compression upper bound...

revlog: add the option to track the expected compression upper bound There are various optimization we can do if we can estimate the size of delta before actually spending CPU compressing them. So we add a attributed dedicated to tracking that. We only use it on Manifest because (1) it structure is quite stable across all Mercurial repository so its compression ratio is fairly universal. This is the revlog with most extreme delta (cf the sparse-revlog optimization). This will be put to use in later changesets. Right now the compression upper bound is set to 10. This is a fairly conservative value (observed value is more around 3), but I prefer to be safe while introducing the optimization principles. We can tune the optimization threshold later.

Yuya Nishihara - - Load All Authors

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             mpatchbuild.py
        
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      from __future__ import absolute_import

      import cffi

      import os

      ffi = cffi.FFI()

      mpatch_c = os.path.join(os.path.join(os.path.dirname(__file__), '..',

                                           'mpatch.c'))

      with open(mpatch_c) as f:

          ffi.set_source("mercurial.cffi._mpatch", f.read(),

                         include_dirs=["mercurial"])

      ffi.cdef("""

      struct mpatch_frag {

             int start, end, len;

             const char *data;

      };

      struct mpatch_flist {

             struct mpatch_frag *base, *head, *tail;

      };

      extern "Python" struct mpatch_flist* cffi_get_next_item(void*, ssize_t);

      int mpatch_decode(const char *bin, ssize_t len, struct mpatch_flist** res);

      ssize_t mpatch_calcsize(size_t len, struct mpatch_flist *l);

      void mpatch_lfree(struct mpatch_flist *a);

      static int mpatch_apply(char *buf, const char *orig, size_t len,

                              struct mpatch_flist *l);

      struct mpatch_flist *mpatch_fold(void *bins,

                             struct mpatch_flist* (*get_next_item)(void*, ssize_t),

                             ssize_t start, ssize_t end);

      """)

      if __name__ == '__main__':

          ffi.compile()

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				from __future__ import absolute_import

				import cffi
				import os

				ffi = cffi.FFI()
				mpatch_c = os.path.join(os.path.join(os.path.dirname(__file__), '..',
				'mpatch.c'))
				with open(mpatch_c) as f:
				ffi.set_source("mercurial.cffi._mpatch", f.read(),
				include_dirs=["mercurial"])
				ffi.cdef("""

				struct mpatch_frag {
				int start, end, len;
				const char *data;
				};

				struct mpatch_flist {
				struct mpatch_frag base, head, *tail;
				};

				extern "Python" struct mpatch_flist* cffi_get_next_item(void*, ssize_t);

				int mpatch_decode(const char bin, ssize_t len, struct mpatch_flist* res);
				ssize_t mpatch_calcsize(size_t len, struct mpatch_flist *l);
				void mpatch_lfree(struct mpatch_flist *a);
				static int mpatch_apply(char buf, const char orig, size_t len,
				struct mpatch_flist *l);
				struct mpatch_flist mpatch_fold(void bins,
				struct mpatch_flist* (get_next_item)(void, ssize_t),
				ssize_t start, ssize_t end);
				""")

				if __name__ == '__main__':
				ffi.compile()