From 0ba1ef0bab39c2ecca77dbbee7d107f7f961ae39 Mon Sep 17 00:00:00 2001
From: Olly Betts <olly@survex.com>
Date: Thu, 18 Feb 2016 19:18:08 +1300
Subject: [PATCH] Fold BtreeCursor::prev() into find_entry_lt()

This is the only place it is used, and we can make several
simplifications based on knowing the context it's called in.
---
 xapian-core/backends/glass/glass_cursor.cc | 68 +++++++++++-------------------
 xapian-core/backends/glass/glass_cursor.h  | 11 +----
 2 files changed, 25 insertions(+), 54 deletions(-)

diff --git a/xapian-core/backends/glass/glass_cursor.cc b/xapian-core/backends/glass/glass_cursor.cc
index ffa4a8bf5..77e38d45c 100644
--- a/xapian-core/backends/glass/glass_cursor.cc
+++ b/xapian-core/backends/glass/glass_cursor.cc
@@ -100,50 +100,6 @@ GlassCursor::~GlassCursor()
 }
 
 bool
-GlassCursor::prev()
-{
-    LOGCALL(DB, bool, "GlassCursor::prev", NO_ARGS);
-    Assert(!is_after_end);
-    if (B->cursor_version != version || !is_positioned) {
-	// Either the cursor needs rebuilding (in which case find_entry() will
-	// call rebuild() and then reposition the cursor), or we've read the
-	// last key and tag, and we're now not positioned (in which case we
-	// seek to the current key, and then it's as if we read the key but not
-	// the tag).
-	if (!find_entry(current_key)) {
-	    // Exact entry was no longer there after rebuild(), and we've
-	    // automatically ended up on the entry before it.
-	    RETURN(true);
-	}
-    } else if (tag_status != UNREAD) {
-	while (true) {
-	    if (! B->prev(C, 0)) {
-		is_positioned = false;
-		RETURN(false);
-	    }
-	    if (LeafItem(C[0].get_p(), C[0].c).component_of() == 1) {
-		break;
-	    }
-	}
-    }
-
-    while (true) {
-	if (! B->prev(C, 0)) {
-	    is_positioned = false;
-	    RETURN(false);
-	}
-	if (LeafItem(C[0].get_p(), C[0].c).component_of() == 1) {
-	    break;
-	}
-    }
-    get_key(&current_key);
-    tag_status = UNREAD;
-
-    LOGLINE(DB, "Moved to entry: key=" << hex_display_encode(current_key));
-    RETURN(true);
-}
-
-bool
 GlassCursor::next()
 {
     LOGCALL(DB, bool, "GlassCursor::next", NO_ARGS);
@@ -228,6 +184,30 @@ done:
     RETURN(found);
 }
 
+void
+GlassCursor::find_entry_lt(const string &key)
+{
+    LOGCALL_VOID(DB, "GlassCursor::find_entry_lt", key);
+    if (!find_entry(key)) {
+	// The entry wasn't found, so find_entry() left us on the entry before
+	// the one we asked for and we're done.
+	return;
+    }
+
+    Assert(!is_after_end);
+    Assert(is_positioned);
+
+    do {
+	if (! B->prev(C, 0)) {
+	    is_positioned = false;
+	    return;
+	}
+    } while (LeafItem(C[0].get_p(), C[0].c).component_of() != 1);
+    get_key(&current_key);
+
+    LOGLINE(DB, "Found entry: key=" << hex_display_encode(current_key));
+}
+
 bool
 GlassCursor::find_exact(const string &key)
 {
diff --git a/xapian-core/backends/glass/glass_cursor.h b/xapian-core/backends/glass/glass_cursor.h
index e7ed3c855..89a1c11a3 100644
--- a/xapian-core/backends/glass/glass_cursor.h
+++ b/xapian-core/backends/glass/glass_cursor.h
@@ -273,13 +273,6 @@ class GlassCursor {
 	 */
 	bool next();
  
-	/** Move to the previous key.
-	 *
-	 *  This is like GlassCursor::next, but BC is taken to the previous
-	 *  rather than next item.
-	 */
-	bool prev();
-
 	/** Position the cursor on the highest entry with key <= @a key.
 	 *
 	 *  If the exact key is found in the table, the cursor will be
@@ -315,9 +308,7 @@ class GlassCursor {
 	bool find_exact(const string &key);
 
 	/// Position the cursor on the highest entry with key < @a key.
-	void find_entry_lt(const string &key) {
-	    if (find_entry(key)) prev();
-	}
+	void find_entry_lt(const string &key);
 
 	/** Position the cursor on the lowest entry with key >= @a key.
 	 *
-- 
2.11.4.GIT