Add support for a WT_CURSOR.reconfigure method, reference #1381.

1 files changed, 79 insertions, 48 deletions

diff --git a/src/cursor/cur_std.c b/src/cursor/cur_std.c
index cba83b1d088..6f7168a5cc6 100644
--- a/src/cursor/cur_std.c
+++ b/src/cursor/cur_std.c
@@ -58,28 +58,6 @@ __wt_cursor_set_notsup(WT_CURSOR *cursor)
 }
 
 /*
- * __wt_cursor_config_readonly --
- *	Parse read only configuration and setup cursor appropriately.
- */
-int
-__wt_cursor_config_readonly(WT_CURSOR *cursor, const char *cfg[], int def)
-{
-	WT_CONFIG_ITEM cval;
-	WT_SESSION_IMPL *session;
-
-	session = (WT_SESSION_IMPL *)cursor->session;
-
-	WT_RET(__wt_config_gets_def(session, cfg, "readonly", def, &cval));
-	if (cval.val != 0) {
-		/* Reset all cursor methods that could modify data. */
-		cursor->insert = __wt_cursor_notsup;
-		cursor->update = __wt_cursor_notsup;
-		cursor->remove = __wt_cursor_notsup;
-	}
-	return (0);
-}
-
-/*
  * __wt_cursor_kv_not_set --
  *	Standard error message for key/values not set.
  */
@@ -501,29 +479,72 @@ __wt_cursor_close(WT_CURSOR *cursor)
 }
 
 /*
- * __cursor_runtime_config --
+ * __wt_cursor_reconfigure --
  *	Set runtime-configurable settings.
  */
-static int
-__cursor_runtime_config(WT_CURSOR *cursor, const char *cfg[])
+int
+__wt_cursor_reconfigure(WT_CURSOR *cursor, const char *config)
 {
 	WT_CONFIG_ITEM cval;
+	WT_DECL_RET;
 	WT_SESSION_IMPL *session;
 
 	session = (WT_SESSION_IMPL *)cursor->session;
 
-	/* 
-	 * !!!
-	 * There's no way yet to reconfigure cursor flags at runtime; if, in
-	 * the future there is a way to do that, similar support needs to be
-	 * added for data-source cursors, or, this call needs to return an
-	 * error in the case of a data-source cursor.
+	/* Reconfiguration resets the cursor. */
+	WT_RET(cursor->reset(cursor));
+
+	/*
+	 * append
+	 * Only relevant to column stores.
 	 */
-	WT_RET(__wt_config_gets_def(session, cfg, "overwrite", 1, &cval));
-	if (cval.val)
-		F_SET(cursor, WT_CURSTD_OVERWRITE);
-	else
-		F_CLR(cursor, WT_CURSTD_OVERWRITE);
+	if (WT_CURSOR_RECNO(cursor)) {
+		if ((ret = __wt_config_getones(
+		    session, config, "append", &cval)) == 0) {
+			if (cval.val)
+				F_SET(cursor, WT_CURSTD_APPEND);
+			else
+				F_CLR(cursor, WT_CURSTD_APPEND);
+		} else
+			WT_RET_NOTFOUND_OK(ret);
+	}
+
+	/*
+	 * overwrite
+	 */
+	if ((ret = __wt_config_getones(
+	    session, config, "overwrite", &cval)) == 0) {
+		if (cval.val)
+			F_SET(cursor, WT_CURSTD_OVERWRITE);
+		else
+			F_CLR(cursor, WT_CURSTD_OVERWRITE);
+	} else
+		WT_RET_NOTFOUND_OK(ret);
+
+	/*
+	 * readonly
+	 */
+	if ((ret = __wt_config_getones(
+	    session, config, "readonly", &cval)) == 0) {
+		if (cval.val == 0) {
+			/*
+			 * Fail if the user is turning readonly off and the
+			 * cursor never supported writing in the first place.
+			 */
+			if (cursor->insert_orig ==
+			    (int (*)(WT_CURSOR *))__wt_cursor_set_notsup)
+				WT_RET_MSG(session, EINVAL,
+				    "cursor cannot be used for data update");
+			cursor->insert = cursor->insert_orig;
+			cursor->remove = cursor->remove_orig;
+			cursor->update = cursor->update_orig;
+		} else {
+			cursor->insert = __wt_cursor_notsup;
+			cursor->remove = __wt_cursor_notsup;
+			cursor->update = __wt_cursor_notsup;
+		}
+	} else
+		WT_RET_NOTFOUND_OK(ret);
 
 	return (0);
 }
@@ -580,15 +601,13 @@ __wt_cursor_init(WT_CURSOR *cursor,
 	WT_CONFIG_ITEM cval;
 	WT_CURSOR *cdump;
 	WT_SESSION_IMPL *session;
+	int readonly;
 
 	session = (WT_SESSION_IMPL *)cursor->session;
 
 	if (cursor->internal_uri == NULL)
 		WT_RET(__wt_strdup(session, uri, &cursor->internal_uri));
 
-	/* Set runtime-configurable settings. */
-	WT_RET(__cursor_runtime_config(cursor, cfg));
-
 	/*
 	 * append
 	 * The append flag is only relevant to column stores.
@@ -600,14 +619,22 @@ __wt_cursor_init(WT_CURSOR *cursor,
 	}
 
 	/*
-	 * checkpoint
-	 * Checkpoint cursors are read-only.
+	 * checkpoint, readonly
+	 * Checkpoint cursors are read-only, avoid any extra work.
 	 */
+	readonly = 0;
 	WT_RET(__wt_config_gets_def(session, cfg, "checkpoint", 0, &cval));
-	if (cval.len != 0) {
-		cursor->insert = __wt_cursor_notsup;
-		cursor->update = __wt_cursor_notsup;
-		cursor->remove = __wt_cursor_notsup;
+	if (cval.len == 0) {
+		WT_RET(
+		    __wt_config_gets_def(session, cfg, "readonly", 0, &cval));
+		if (cval.val != 0)
+			readonly = 1;
+	} else
+		readonly = 1;
+	if (readonly) {
+		cursor->insert = cursor->insert_orig = __wt_cursor_notsup;
+		cursor->update = cursor->update_orig = __wt_cursor_notsup;
+		cursor->remove = cursor->remove_orig = __wt_cursor_notsup;
 	}
 
 	/*
@@ -634,14 +661,18 @@ __wt_cursor_init(WT_CURSOR *cursor,
 	} else
 		cdump = NULL;
 
+	/* overwrite */
+	WT_RET(__wt_config_gets_def(session, cfg, "overwrite", 1, &cval));
+	if (cval.val)
+		F_SET(cursor, WT_CURSTD_OVERWRITE);
+	else
+		F_CLR(cursor, WT_CURSTD_OVERWRITE);
+
 	/* raw */
 	WT_RET(__wt_config_gets_def(session, cfg, "raw", 0, &cval));
 	if (cval.val != 0)
 		F_SET(cursor, WT_CURSTD_RAW);
 
-	/* readonly */
-	WT_RET(__wt_cursor_config_readonly(cursor, cfg, 0));
-
 	/*
 	 * Cursors that are internal to some other cursor (such as file cursors
 	 * inside a table cursor) should be closed after the containing cursor.