optimize encryption api

only one encryption key lookup in most cases instead of three
(has_key, get_key_size, get_key).

include/mysql/plugin_audit.h.pp

@@ -201,13 +201,11 @@ int thd_setspecific(void* thd, MYSQL_THD_KEY_T key, void *value);
 extern struct encryption_keys_service_st {
   unsigned int (*get_latest_encryption_key_version_func)();
   unsigned int (*has_encryption_key_func)(unsigned int);
-  unsigned int (*get_encryption_key_size_func)(unsigned int);
-  int (*get_encryption_key_func)(unsigned int, unsigned char*, unsigned int);
+  unsigned int (*get_encryption_key_func)(unsigned int, unsigned char*, unsigned int*);
 } *encryption_keys_service;
 unsigned int get_latest_encryption_key_version();
 unsigned int has_encryption_key(unsigned int version);
-unsigned int get_encryption_key_size(unsigned int version);
-int get_encryption_key(unsigned int version, unsigned char* key, unsigned int keybufsize);
+unsigned int get_encryption_key(unsigned int version, unsigned char* key, unsigned int *keybufsize);
 struct st_mysql_xid {
   long formatID;
   long gtrid_length;

include/mysql/plugin_auth.h.pp

@@ -201,13 +201,11 @@ int thd_setspecific(void* thd, MYSQL_THD_KEY_T key, void *value);
 extern struct encryption_keys_service_st {
   unsigned int (*get_latest_encryption_key_version_func)();
   unsigned int (*has_encryption_key_func)(unsigned int);
-  unsigned int (*get_encryption_key_size_func)(unsigned int);
-  int (*get_encryption_key_func)(unsigned int, unsigned char*, unsigned int);
+  unsigned int (*get_encryption_key_func)(unsigned int, unsigned char*, unsigned int*);
 } *encryption_keys_service;
 unsigned int get_latest_encryption_key_version();
 unsigned int has_encryption_key(unsigned int version);
-unsigned int get_encryption_key_size(unsigned int version);
-int get_encryption_key(unsigned int version, unsigned char* key, unsigned int keybufsize);
+unsigned int get_encryption_key(unsigned int version, unsigned char* key, unsigned int *keybufsize);
 struct st_mysql_xid {
   long formatID;
   long gtrid_length;

include/mysql/plugin_encryption_key_management.h

@@ -27,9 +27,10 @@
 
 #include <mysql/plugin.h>
 
-#define MariaDB_ENCRYPTION_KEY_MANAGEMENT_INTERFACE_VERSION 0x0100
+#define MariaDB_ENCRYPTION_KEY_MANAGEMENT_INTERFACE_VERSION 0x0200
 
-#define BAD_ENCRYPTION_KEY_VERSION (UINT_MAX32)
+#define BAD_ENCRYPTION_KEY_VERSION (~(unsigned int)0)
+#define KEY_BUFFER_TOO_SMALL       (100)
 
 /**
   Encryption key management plugin descriptor
@@ -45,20 +46,28 @@ struct st_mariadb_encryption_key_management
   */
   unsigned int (*get_latest_key_version)();
 
-  /** function returning if a key of the given version exists */
-  unsigned int (*has_key_version)(unsigned int version);
-
-  /** function returning the key size in bytes */
-  unsigned int (*get_key_size)(unsigned int version);
-
   /**
     function returning a key for a key version
 
-    the key is put in 'key' buffer, that has size of 'keybufsize' bytes.
+    @param version      the requested key version
+    @param key          the key will be stored there. Can be NULL -
+                        in which case no key will be returned
+    @param key_length   in: key buffer size
+                        out: the actual length of the key
 
-    @return 0 on success, non-zero on failure
+    This method can be used to query the key length - the required
+    buffer size - by passing key==NULL.
+
+    If the buffer size is less than the key length the content of the
+    key buffer is undefined (the plugin is free to partially fill it with
+    the key data or leave it untouched).
+
+    @return 0 on success, or
+            BAD_ENCRYPTION_KEY_VERSION, KEY_BUFFER_TOO_SMALL,
+            or any other non-zero number for errors
   */
-  int (*get_key)(unsigned int version, unsigned char* key, unsigned int keybufsize);
+  unsigned int (*get_key)(unsigned int version, unsigned char *key,
+                          unsigned int *key_length);
 };
 #endif
 

include/mysql/plugin_encryption_key_management.h.pp

@@ -201,13 +201,11 @@ int thd_setspecific(void* thd, MYSQL_THD_KEY_T key, void *value);
 extern struct encryption_keys_service_st {
   unsigned int (*get_latest_encryption_key_version_func)();
   unsigned int (*has_encryption_key_func)(unsigned int);
-  unsigned int (*get_encryption_key_size_func)(unsigned int);
-  int (*get_encryption_key_func)(unsigned int, unsigned char*, unsigned int);
+  unsigned int (*get_encryption_key_func)(unsigned int, unsigned char*, unsigned int*);
 } *encryption_keys_service;
 unsigned int get_latest_encryption_key_version();
 unsigned int has_encryption_key(unsigned int version);
-unsigned int get_encryption_key_size(unsigned int version);
-int get_encryption_key(unsigned int version, unsigned char* key, unsigned int keybufsize);
+unsigned int get_encryption_key(unsigned int version, unsigned char* key, unsigned int *keybufsize);
 struct st_mysql_xid {
   long formatID;
   long gtrid_length;
@@ -368,7 +366,6 @@ struct st_mariadb_encryption_key_management
 {
   int interface_version;
   unsigned int (*get_latest_key_version)();
-  unsigned int (*has_key_version)(unsigned int version);
-  unsigned int (*get_key_size)(unsigned int version);
-  int (*get_key)(unsigned int version, unsigned char* key, unsigned int keybufsize);
+  unsigned int (*get_key)(unsigned int version, unsigned char *key,
+                          unsigned int *key_length);
 };

include/mysql/plugin_ftparser.h.pp

@@ -201,13 +201,11 @@ int thd_setspecific(void* thd, MYSQL_THD_KEY_T key, void *value);
 extern struct encryption_keys_service_st {
   unsigned int (*get_latest_encryption_key_version_func)();
   unsigned int (*has_encryption_key_func)(unsigned int);
-  unsigned int (*get_encryption_key_size_func)(unsigned int);
-  int (*get_encryption_key_func)(unsigned int, unsigned char*, unsigned int);
+  unsigned int (*get_encryption_key_func)(unsigned int, unsigned char*, unsigned int*);
 } *encryption_keys_service;
 unsigned int get_latest_encryption_key_version();
 unsigned int has_encryption_key(unsigned int version);
-unsigned int get_encryption_key_size(unsigned int version);
-int get_encryption_key(unsigned int version, unsigned char* key, unsigned int keybufsize);
+unsigned int get_encryption_key(unsigned int version, unsigned char* key, unsigned int *keybufsize);
 struct st_mysql_xid {
   long formatID;
   long gtrid_length;

include/mysql/plugin_password_validation.h.pp

@@ -201,13 +201,11 @@ int thd_setspecific(void* thd, MYSQL_THD_KEY_T key, void *value);
 extern struct encryption_keys_service_st {
   unsigned int (*get_latest_encryption_key_version_func)();
   unsigned int (*has_encryption_key_func)(unsigned int);
-  unsigned int (*get_encryption_key_size_func)(unsigned int);
-  int (*get_encryption_key_func)(unsigned int, unsigned char*, unsigned int);
+  unsigned int (*get_encryption_key_func)(unsigned int, unsigned char*, unsigned int*);
 } *encryption_keys_service;
 unsigned int get_latest_encryption_key_version();
 unsigned int has_encryption_key(unsigned int version);
-unsigned int get_encryption_key_size(unsigned int version);
-int get_encryption_key(unsigned int version, unsigned char* key, unsigned int keybufsize);
+unsigned int get_encryption_key(unsigned int version, unsigned char* key, unsigned int *keybufsize);
 struct st_mysql_xid {
   long formatID;
   long gtrid_length;

include/mysql/service_encryption_keys.h

@@ -28,23 +28,20 @@ extern "C" {
 extern struct encryption_keys_service_st {
   unsigned int (*get_latest_encryption_key_version_func)();
   unsigned int (*has_encryption_key_func)(unsigned int);
-  unsigned int (*get_encryption_key_size_func)(unsigned int);
-  int (*get_encryption_key_func)(unsigned int, unsigned char*, unsigned int);
+  unsigned int (*get_encryption_key_func)(unsigned int, unsigned char*, unsigned int*);
 } *encryption_keys_service;
 
 #ifdef MYSQL_DYNAMIC_PLUGIN
 
 #define get_latest_encryption_key_version() encryption_keys_service->get_latest_encryption_key_version_func()
 #define has_encryption_key(V) encryption_keys_service->has_encryption_key_func(V)
-#define get_encryption_key_size(V) encryption_keys_service->get_encryption_key_size_func(V)
 #define get_encryption_key(V,K,S) encryption_keys_service->get_encryption_key_func((V), (K), (S))
 
 #else
 
 unsigned int get_latest_encryption_key_version();
 unsigned int has_encryption_key(unsigned int version);
-unsigned int get_encryption_key_size(unsigned int version);
-int get_encryption_key(unsigned int version, unsigned char* key, unsigned int keybufsize);
+unsigned int get_encryption_key(unsigned int version, unsigned char* key, unsigned int *keybufsize);
 
 #endif