Windows has its own ftruncate() called _chsize_s().
p_mkstemp() is changed to use p_open() so we can make sure we open for
writing; the addition of exclusive create is a good thing to do
regardless, as we want a temporary path for ourselves.
Lastly, MSVC doesn't quite know how to add two numbers if one of them is a
void pointer, so let's alias it to unsigned char.C
Some OSs cannot keep their ideas about file content straight when mixing
standard IO with file mapping. As we use mmap for reading from the
packfile, let's make writing to the pack file use mmap.
When running multithreaded, it is not enough to check for the offmap
allocation. Move the call to cache_init() to packfile allocation so we
can be sure it is always allocated free of races.
This fixes#2355.
There are a number of tests that modify the global or system
search paths during the tests. This adds a helper function to
make it easier to restore those paths and makes sure that they
are getting restored in a manner that preserves test isolation.
The switch makes the loop somewhat unwieldy. Let's assume it's fine and
perform the check when we're accessing the data.
This makes our code look a lot more like git's.
Dependency chains are often large and require a few
reallocations. Allocate a 64-element chain before doing anything else to
avoid allocations during the loop.
This value comes from the stack-allocated one git uses. We still
allocate this on the heap, but it does help performance a little bit.
Bring back the use of the delta base cache for unpacking objects. When
generating the delta chain, we stop when we find a delta base in the
pack's cache and use that as the starting point.
We currently make use of recursive function calls to unpack an object,
resolving the deltas as we come back down the chain. This means that we
have unbounded stack growth as we look up objects in a pack.
This is now done in two steps: first we figure out what the dependency
chain is by looking up the delta bases until we reach a non-delta
object, pushing the information we need onto a stack and then we pop
from that stack and apply the deltas until there are no more left.
This version of the code does not make use of the delta base cache so it
is slower than what's in the mainline. A later commit will reintroduce
it.
