libmemcached: fix #41 (ensure stable sort on host key collision)

[awesomized/libmemcached] / libmemcached / hosts.cc

diff --git a/libmemcached/hosts.cc b/libmemcached/hosts.cc
index 747245f956df0d600f076f106d6d3773d0da9ff2..98cb3f7d48dc777c1d4ca18f1c3f75b7a471f771 100644 (file)
--- a/libmemcached/hosts.cc
+++ b/libmemcached/hosts.cc
@@ -46,8 +46,8 @@ static memcached_return_t update_continuum(Memcached *ptr);
 
 static int compare_servers(const void *p1, const void *p2)
 {
-  memcached_server_instance_st a= (memcached_server_instance_st)p1;
-  memcached_server_instance_st b= (memcached_server_instance_st)p2;
+  const memcached_instance_st * a= (const memcached_instance_st *)p1;
+  const memcached_instance_st * b= (const memcached_instance_st *)p2;
 
   int return_value= strcmp(a->_hostname, b->_hostname);
 
@@ -63,7 +63,7 @@ static void sort_hosts(Memcached *ptr)
 {
   if (memcached_server_count(ptr))
   {
-    qsort(memcached_instance_list(ptr), memcached_server_count(ptr), sizeof(org::libmemcached::Instance), compare_servers);
+    qsort(memcached_instance_list(ptr), memcached_server_count(ptr), sizeof(memcached_instance_st), compare_servers);
   }
 }
 
@@ -120,7 +120,18 @@ static int continuum_item_cmp(const void *t1, const void *t2)
   WATCHPOINT_ASSERT(ct1->value != 153);
   if (ct1->value == ct2->value)
   {
-    return 0;
+    if (ct1->index == ct2->index)
+    {
+      return 0;
+    }
+    else if (ct1->index > ct2->index)
+    {
+      return 1;
+    }
+    else
+    {
+      return -1;
+    }
   }
   else if (ct1->value > ct2->value)
   {
@@ -146,7 +157,7 @@ static memcached_return_t update_continuum(Memcached *ptr)
     return memcached_set_errno(*ptr, errno, MEMCACHED_AT);
   }
 
-  org::libmemcached::Instance* list= memcached_instance_list(ptr);
+  memcached_instance_st* list= memcached_instance_list(ptr);
 
   /* count live servers (those without a retry delay set) */
   bool is_auto_ejecting= _is_auto_eject_host(ptr);
@@ -174,18 +185,20 @@ static memcached_return_t update_continuum(Memcached *ptr)
     live_servers= memcached_server_count(ptr);
   }
 
-  uint32_t points_per_server= (uint32_t) (memcached_is_weighted_ketama(ptr) ? MEMCACHED_POINTS_PER_SERVER_KETAMA : MEMCACHED_POINTS_PER_SERVER);
-
   if (live_servers == 0)
   {
     return MEMCACHED_SUCCESS;
   }
 
-  if (live_servers > ptr->ketama.continuum_count)
+  uint32_t points_per_server = (uint32_t) (memcached_is_weighted_ketama(ptr) ? MEMCACHED_POINTS_PER_SERVER_KETAMA : MEMCACHED_POINTS_PER_SERVER);
+  uint32_t continuum_limit = live_servers * points_per_server;
+  uint32_t continuum_extra = MEMCACHED_CONTINUUM_ADDITION * points_per_server;
+
+  if (continuum_limit > ptr->ketama.continuum_count)
   {
     memcached_continuum_item_st *new_ptr;
 
-    new_ptr= libmemcached_xrealloc(ptr, ptr->ketama.continuum, (live_servers + MEMCACHED_CONTINUUM_ADDITION) * points_per_server, memcached_continuum_item_st);
+    new_ptr= libmemcached_xrealloc(ptr, ptr->ketama.continuum, continuum_limit + continuum_extra, memcached_continuum_item_st);
 
     if (new_ptr == 0)
     {
@@ -193,7 +206,7 @@ static memcached_return_t update_continuum(Memcached *ptr)
     }
 
     ptr->ketama.continuum= new_ptr;
-    ptr->ketama.continuum_count= live_servers + MEMCACHED_CONTINUUM_ADDITION;
+    ptr->ketama.continuum_count= continuum_limit + continuum_extra;
   }
   assert_msg(ptr->ketama.continuum, "Programmer Error, empty ketama continuum");
 
@@ -221,7 +234,7 @@ static memcached_return_t update_continuum(Memcached *ptr)
         float pct= (float)list[host_index].weight / (float)total_weight;
         pointer_per_server= (uint32_t) ((::floor((float) (pct * MEMCACHED_POINTS_PER_SERVER_KETAMA / 4 * (float)live_servers + 0.0000000001))) * 4);
         pointer_per_hash= 4;
-        if (DEBUG)
+        if (0 && DEBUG)
         {
           printf("ketama_weighted:%s|%d|%llu|%u\n",
                  list[host_index]._hostname,
@@ -255,7 +268,7 @@ static memcached_return_t update_continuum(Memcached *ptr)
                                      memcached_literal_param("snprintf(sizeof(sort_host))"));
         }
 
-        if (DEBUG)
+        if (0 && DEBUG)
         {
           fprintf(stdout, "update_continuum: key is %s\n", sort_host);
         }
@@ -365,7 +378,7 @@ static memcached_return_t server_add(Memcached *memc,
   }
 
   uint32_t host_list_size= memc->number_of_hosts +1;
-  org::libmemcached::Instance* new_host_list= libmemcached_xrealloc(memc, memcached_instance_list(memc), host_list_size, org::libmemcached::Instance);
+  memcached_instance_st* new_host_list= libmemcached_xrealloc(memc, memcached_instance_list(memc), host_list_size, memcached_instance_st);
 
   if (new_host_list == NULL)
   {
@@ -376,7 +389,7 @@ static memcached_return_t server_add(Memcached *memc,
   assert(memc->number_of_hosts == host_list_size);
 
   /* TODO: Check return type */
-  org::libmemcached::Instance* instance= memcached_instance_fetch(memc, memcached_server_count(memc) -1);
+  memcached_instance_st* instance= memcached_instance_fetch(memc, memcached_server_count(memc) -1);
 
   if (__instance_create_with(memc, instance, hostname, port, weight, type) == NULL)
   {
@@ -409,7 +422,7 @@ memcached_return_t memcached_server_push(memcached_st *shell, const memcached_se
     uint32_t count= memcached_server_list_count(list);
     uint32_t host_list_size= count +original_host_size;
 
-    org::libmemcached::Instance* new_host_list= libmemcached_xrealloc(ptr, memcached_instance_list(ptr), host_list_size, org::libmemcached::Instance);
+    memcached_instance_st* new_host_list= libmemcached_xrealloc(ptr, memcached_instance_list(ptr), host_list_size, memcached_instance_st);
 
     if (new_host_list == NULL)
     {
@@ -424,7 +437,7 @@ memcached_return_t memcached_server_push(memcached_st *shell, const memcached_se
       WATCHPOINT_ASSERT(list[x].hostname[0] != 0);
 
       // We have extended the array, and now we will find it, and use it.
-      org::libmemcached::Instance* instance= memcached_instance_fetch(ptr, original_host_size);
+      memcached_instance_st* instance= memcached_instance_fetch(ptr, original_host_size);
       WATCHPOINT_ASSERT(instance);
 
       memcached_string_t hostname= { memcached_string_make_from_cstr(list[x].hostname) };
@@ -449,7 +462,7 @@ memcached_return_t memcached_server_push(memcached_st *shell, const memcached_se
   return MEMCACHED_INVALID_ARGUMENTS;
 }
 
-memcached_return_t memcached_instance_push(memcached_st *ptr, const struct org::libmemcached::Instance* list, uint32_t number_of_hosts)
+memcached_return_t memcached_instance_push(memcached_st *ptr, const struct memcached_instance_st* list, uint32_t number_of_hosts)
 {
   if (list == NULL)
   {
@@ -458,7 +471,7 @@ memcached_return_t memcached_instance_push(memcached_st *ptr, const struct org::
 
   uint32_t original_host_size= memcached_server_count(ptr);
   uint32_t host_list_size= number_of_hosts +original_host_size;
-  org::libmemcached::Instance* new_host_list= libmemcached_xrealloc(ptr, memcached_instance_list(ptr), host_list_size, org::libmemcached::Instance);
+  memcached_instance_st* new_host_list= libmemcached_xrealloc(ptr, memcached_instance_list(ptr), host_list_size, memcached_instance_st);
 
   if (new_host_list == NULL)
   {
@@ -477,7 +490,7 @@ memcached_return_t memcached_instance_push(memcached_st *ptr, const struct org::
     WATCHPOINT_ASSERT(list[x]._hostname[0] != 0);
 
     // We have extended the array, and now we will find it, and use it.
-    org::libmemcached::Instance* instance= memcached_instance_fetch(ptr, original_host_size);
+    memcached_instance_st* instance= memcached_instance_fetch(ptr, original_host_size);
     WATCHPOINT_ASSERT(instance);
 
     memcached_string_t hostname= { memcached_string_make_from_cstr(list[x]._hostname) };
@@ -591,7 +604,7 @@ memcached_return_t memcached_server_add_parsed(memcached_st *ptr,
                                                in_port_t port,
                                                uint32_t weight)
 {
-  char buffer[MEMCACHED_NI_MAXHOST];
+  char buffer[MEMCACHED_NI_MAXHOST]= { 0 };
 
   memcpy(buffer, hostname, hostname_length);
   buffer[hostname_length]= 0;