cache: use threads instead of fork()

Basically rewrite all the code supporting the cache (i.e. anything other
than the ringbuffer logic). The underlying design is untouched.

Note that the old cache2.c (on which this code is based) already had a
threading implementation. This was mostly unused on Linux, and had some
problems, such as using shared volatile variables for communication and
uninterruptible timeouts, instead of using locks for synchronization.

This commit does use proper locking, while still retaining the way the
old cache worked. It's basically a big refactor.

Simplify the code too. Since we don't need to copy stream ctrl args
anymore (we're always guaranteed a shared address space now), lots of
annoying code just goes away. Likewise, we don't need to care about
sector sizes. The cache uses the high-level stream API to read from
other streams, and sector sizes are handled transparently.

1 files changed, 5 insertions, 4 deletions

diff --git a/configure b/configure
index f01c515c54..d18d1cc547 100755
--- a/configure
+++ b/configure
@@ -493,7 +493,6 @@ libavdevice=auto
 _stream_cache=yes
 _priority=no
 def_dos_paths="#define HAVE_DOS_PATHS 0"
-def_stream_cache="#define CONFIG_STREAM_CACHE 1"
 def_priority="#undef CONFIG_PRIORITY"
 need_shmem=yes
 _build_man=auto
@@ -1452,9 +1451,11 @@ else
 fi
 echores "$_pthreads"
 
-if cygwin || mingw32 ; then
-  _stream_cache=no
-  def_stream_cache="#undef CONFIG_STREAM_CACHE"
+_stream_cache="$_pthreads"
+if test "$_stream_cache" = yes ; then
+  def_stream_cache='#define CONFIG_STREAM_CACHE'
+else
+  def_stream_cache='#undef CONFIG_STREAM_CACHE'
 fi
 
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