Import wiredtiger: af735d14a603a6ef6256a6685f09ec13755a5024 from branch mongodb-3.6

ref: cc2f15f595..af735d14a6
for: 3.5.6

SERVER-28168  Cannot start or repair mongodb after unexpected shutdown.
SERVER-28194  Missing WiredTiger.turtle file loses data
WT-2439       Enhance reconciliation page layout
WT-2978       Make WiredTiger python binding pip-compatible
WT-2990       Fix a new bug where checkpoint load live_open failed
WT-3136       bug fix: WiredTiger doesn't check sprintf calls for error return
WT-3155       Remove WT_CONN_SERVER_RUN flag
WT-3182       Switch make-check to run the short test suite by default
WT-3190       Enhance eviction thread auto-tuning algorithm
WT-3191       Fix lint complaints
WT-3193       Close a race between verify opening a handle and eviction visiting it
WT-3196       Race with LSM and eviction when switching chunks
WT-3199       bug: eviction assertion failure
WT-3202       wtperf report an error on in_memory=true mode : No such file or directory
WT-3203       bulk-load state changes can race
WT-3204       eviction changes cost LSM performance
WT-3206       bug: core dump on NULL page index
WT-3207       Drops with checkpoint_wait=false should not wait for checkpoints
WT-3208       test format hung with 9mb cache
WT-3211       WT_CURSOR.remove cannot always retain its position.
WT-3212       'wt dump' crashes when given table with unknown collator
WT-3213       generated test/format CONFIG invalid on next run
WT-3216       add support for clang-tidy
WT-3218       unexpected checkpoint ordering failures
WT-3224       LSM assertion failure pindex->entries == 1
WT-3225       WiredTiger won't build with clang on CentOS 7.3.1611
WT-3227       Python test suite inserts unnecessary whitespace in error output.
WT-3228       Remove with overwrite shouldn't return WT_NOTFOUND
WT-3234       Update WiredTiger build for clang 4.0.
WT-3238       Java: Cursor.compare and Cursor.equals throw Exceptions for valid return values
WT-3240       Coverity reports
WT-3243       Reorder log slot release so joins don't wait on IO
WT-3244       Metadata operations failing in in-memory configurations when the cache is full
WT-98         Update the current cursor value without a search

1 files changed, 20 insertions, 17 deletions

diff --git a/src/third_party/wiredtiger/src/include/buf.i b/src/third_party/wiredtiger/src/include/buf.i
index ebbee6b4633..d192e292dcf 100644
--- a/src/third_party/wiredtiger/src/include/buf.i
+++ b/src/third_party/wiredtiger/src/include/buf.i
@@ -37,28 +37,30 @@ __wt_buf_extend(WT_SESSION_IMPL *session, WT_ITEM *buf, size_t size)
 
 /*
  * __wt_buf_init --
- *	Initialize a buffer at a specific size.
+ *	Create an empty buffer at a specific size.
  */
 static inline int
 __wt_buf_init(WT_SESSION_IMPL *session, WT_ITEM *buf, size_t size)
 {
+	/*
+	 * The buffer grow function does what we need, but anticipates data
+	 * referenced by the buffer. Avoid any data copy by setting data to
+	 * reference the buffer's allocated memory, and clearing it.
+	 */
 	buf->data = buf->mem;
-	buf->size = 0;				/* Clear existing data length */
-	WT_RET(__wt_buf_grow(session, buf, size));
-
-	return (0);
+	buf->size = 0;
+	return (__wt_buf_grow(session, buf, size));
 }
 
 /*
  * __wt_buf_initsize --
- *	Initialize a buffer at a specific size, and set the data length.
+ *	Create an empty buffer at a specific size, and set the data length.
  */
 static inline int
 __wt_buf_initsize(WT_SESSION_IMPL *session, WT_ITEM *buf, size_t size)
 {
-	buf->data = buf->mem;
-	buf->size = 0;				/* Clear existing data length */
-	WT_RET(__wt_buf_grow(session, buf, size));
+	WT_RET(__wt_buf_init(session, buf, size));
+
 	buf->size = size;			/* Set the data length. */
 
 	return (0);
@@ -72,14 +74,15 @@ static inline int
 __wt_buf_set(
     WT_SESSION_IMPL *session, WT_ITEM *buf, const void *data, size_t size)
 {
-	/* Ensure the buffer is large enough. */
-	WT_RET(__wt_buf_initsize(session, buf, size));
-
-	/* Copy the data, allowing for overlapping strings. */
-	if (size != 0)
-		memmove(buf->mem, data, size);
-
-	return (0);
+	/*
+	 * The buffer grow function does what we need, but expects the data to
+	 * be referenced by the buffer. If we're copying data from outside the
+	 * buffer, set it up so it makes sense to the buffer grow function. (No
+	 * test needed, this works if WT_ITEM.data is already set to "data".)
+	 */
+	buf->data = data;
+	buf->size = size;
+	return (__wt_buf_grow(session, buf, size));
 }
 
 /*