From 0aeedf657c66db2208c0038c6b63aaaba3eaab94 Mon Sep 17 00:00:00 2001
From: Sage Weil <sage@inktank.com>
Date: Thu, 4 Oct 2012 11:04:53 -0700
Subject: [PATCH] librbd: generate format_string in ImageCtx

Prebuild the format string on image load so that it is handy at all times.

Signed-off-by: Sage Weil <sage@inktank.com>
---
 src/librbd/ImageCtx.cc | 25 +++++++++++++++++++++++--
 src/librbd/ImageCtx.h  |  2 ++
 2 files changed, 25 insertions(+), 2 deletions(-)

diff --git a/src/librbd/ImageCtx.cc b/src/librbd/ImageCtx.cc
index 1b673e18ac40f..512d8cbc39ec6 100644
--- a/src/librbd/ImageCtx.cc
+++ b/src/librbd/ImageCtx.cc
@@ -45,7 +45,9 @@ namespace librbd {
       parent_lock("librbd::ImageCtx::parent_lock"),
       refresh_lock("librbd::ImageCtx::refresh_lock"),
       old_format(true),
-      order(0), size(0), features(0),	id(image_id), parent(NULL),
+      order(0), size(0), features(0),
+      format_string(NULL),
+      id(image_id), parent(NULL),
       stripe_unit(0), stripe_count(0),
       object_cacher(NULL), writeback_handler(NULL), object_set(NULL)
   {
@@ -92,6 +94,7 @@ namespace librbd {
       delete object_set;
       object_set = NULL;
     }
+    delete format_string;
   }
 
   int ImageCtx::init() {
@@ -153,9 +156,21 @@ namespace librbd {
     layout.fl_object_size = 1ull << order;
     layout.fl_pg_pool = data_ctx.get_id();  // FIXME: pool id overflow?
 
+    delete format_string;
+    size_t len = object_prefix.length() + 16;
+    format_string = new char[len];
+    if (old_format) {
+      snprintf(format_string, len, "%s.%%012llx", object_prefix.c_str());
+    } else {
+      snprintf(format_string, len, "%s.%%016llx", object_prefix.c_str());
+    }
+
     ldout(cct, 10) << "init_layout stripe_unit " << stripe_unit
 		   << " stripe_count " << stripe_count
-		   << " object_size " << layout.fl_object_size << dendl;
+		   << " object_size " << layout.fl_object_size
+		   << " prefix " << object_prefix
+		   << " format " << format_string
+		   << dendl;
   }
 
   void ImageCtx::perf_start(string name) {
@@ -266,6 +281,12 @@ namespace librbd {
     return 1ull << order;
   }
 
+  string ImageCtx::get_object_name(uint64_t num) const {
+    char buf[object_prefix.length() + 32];
+    snprintf(buf, sizeof(buf), format_string, num);
+    return string(buf);
+  }
+
   uint64_t ImageCtx::get_stripe_unit() const
   {
     return stripe_unit;
diff --git a/src/librbd/ImageCtx.h b/src/librbd/ImageCtx.h
index f952ef621defc..1c58a4ce026cb 100644
--- a/src/librbd/ImageCtx.h
+++ b/src/librbd/ImageCtx.h
@@ -72,6 +72,7 @@ namespace librbd {
     uint64_t size;
     uint64_t features;
     std::string object_prefix;
+    char *format_string;
     std::string header_oid;
     std::string id; // only used for new-format images
     parent_info parent_md;
@@ -106,6 +107,7 @@ namespace librbd {
 
     uint64_t get_size() const;
     uint64_t get_object_size() const;
+    string get_object_name(uint64_t num) const;
     uint64_t get_num_objects() const;
     uint64_t get_stripe_unit() const;
     uint64_t get_stripe_count() const;
-- 
2.39.5