From 8ecd056159345fdbbb6ba0500a7b1cdd5001be6c Mon Sep 17 00:00:00 2001
From: sage <sage@29311d96-e01e-0410-9327-a35deaab8ce9>
Date: Wed, 29 Jun 2005 07:20:03 +0000
Subject: [PATCH] *** empty log message ***

git-svn-id: https://ceph.svn.sf.net/svnroot/ceph@365 29311d96-e01e-0410-9327-a35deaab8ce9
---
 ceph/client/buffercache.h | 133 --------------------------------------
 1 file changed, 133 deletions(-)
 delete mode 100644 ceph/client/buffercache.h

diff --git a/ceph/client/buffercache.h b/ceph/client/buffercache.h
deleted file mode 100644
index f8a0a0597267..000000000000
--- a/ceph/client/buffercache.h
+++ /dev/null
@@ -1,133 +0,0 @@
-#ifndef __BUFFERCACHE_H
-#define __BUFFERCACHE_H
-
-#include "include/buffer.h"
-#include "include/bufferlist.h"
-#include "include/lru.h"
-
-/** map<off_t, bufferptr> buffer_map;
-
-for writes:
-
-void map_or_alloc(size_t len, off_t off, bufferlist &blist);
-- build a bufferlist that includes bufferptr's for existing buffers 
-  in the map and (if necessary) newly allocated ones.  caller can then use
-
-  blist.copy_from(int off, int len, char *buf);
-
-  to copy data into the bufferlist.  (copy() copies data _out_, and append appends, 
-  but copy_from or copy_into or whatever doesn't exist yet.)
-
-
-  for reads:
-  void map_existing(size_t len, off_t off, map<off_t, bufferlist>& hits, map<off_t, size_t>& holes)
-  
-- gives caller map of hits and holes.
-
-
-both of those could be wrapped up in a tidy class, aside from 2 things:
-
-- buffers need to be put in an lru of some sort with last_accessed etc. 
-  so we can flush them intelligently
-
-- maybe the buffers should be allocated w/ fixed size?  for writes at least, 
-  the new buffers can always be created as 256k (or whatever) and the bufferptrs 
-  that reference them (in buffer_map) will point to the relevant substring.  
-  the map_or_alloc() bit just needs to be smart then to check the underlying 
-  buffer's alloc'd size and adjust those subsets as necessary.
-
-  for reads, we'll be getting buffers of weird sizes coming from osds, 
-  so the cache should work with weird sized buffers regardless.  
-  (even if we always prefetch large blocks, files tails will come back small.)
-
-
-  so somewhere in there there should be a buffer_head struct or something. maybe it shoudl be
-
-  map<off_t, bufferhead> buffer_map;
-
-  we can reuse the LRU (include/lru.h) thinger to handle lru stuff pretty easily. 
-  maybe
-
-  class bufferhead : public LRUObject {
-  bufferptr bptr;
-  time_t    last_written;
-  int       state;  // clean, dirty, writing, reading
-  };
-
-gets weird too if say multiple reads are issued on the same (or overlapping) ranges of bytes.. 
-only want to submit a single read request.
-
-s
-*/
-
-// bufferhead states
-#define BUFHD_STATE_CLEAN	1
-#define BUFHD_STATE_DIRTY	2
-#define BUFHD_STATE_WRITING	3
-#define BUFHD_STATE_READING	4
-
-class bufferhead : public LRUObject {
-  bufferptr	bptr;
-  time_t	last_written;
-  int		state;
-};
-
-class buffercache {
- private:
-  map<off_t, bufferhead> buffer_map;
-  
-  map<off_t, bufferhead>::iterator overlap(size_t len, off_t off)
-  {
-    // returns iterator to buffer overlapping specified extent or end() if no overlap exists
-    map<off_t, bufferhead>::iterator it = buffer_map.lower_bound(off);
-    if (it == buffer_map.end() || (*it)->first < off + len) {
-      return it;
-    } else if (it == buffer_map.begin()) {
-      return buffer_map.end();
-    } else {
-      --it;
-      if ((*it)->first + (*it)->second.bptr.length() > off) {
-        return it;
-      } else {
-        return buffer_map.end();
-      }
-    }
-  }
-
- public:
-  /* for writes
-     build a bufferlist that includes bufferptr's for existing buffers 
-     in the map and (if necessary) newly allocated ones.  caller can then use
-	 
-	 blist.copy_from(int off, int len, char *buf);
-	 
-	 to copy data into the bufferlist. (copy() copies data _out_, and append appends, 
-	 but copy_from or copy_into or whatever doesn't exist yet.)
-  */
-  void map_or_alloc(size_t len, off_t off, bufferlist &blist)
-  {
-  }
-
-  /* for reads
-     gives caller maps of hits and holes
-  */
-  void map_existing(size_t len, off_t off, map<off_t, bufferhead>& hits, map<off_t, size_t>& holes)
-  {
-    off_t next_off = off;
-    for (map<off_t, bufferhead>::iterator it = overlap(len, off);
-         it != buffer_map.end() && (*it)->first < off + len;
-         it++) {
-      if ((*it)->first > next_off) {
-        holes[next_off] = (size_t) ((*it)->first - next_off);
-      }
-      hits[(*it)->first] = (*it)->second;
-      next_off = (*it)->first + (*it)->second.bptr.length();
-    }
-    if (next_off < off + len) {
-      holes[next_off] = (size_t) (off + len - next_off);
-    }
-  }
-};
-
-#endif
-
-- 
2.47.3