Fix bug #3443, better foreign key error messsages.

innobase/dict/dict0dict.c:
  Add 'add_newline' parameter to dict_print_info_on_foreign_key_in_create_format.
innobase/include/dict0dict.h:
  Add 'add_newline' parameter to dict_print_info_on_foreign_key_in_create_format.
innobase/include/os0file.h:
  Add os_file_read_string.
innobase/include/trx0trx.h:
  Add trx_set_detailed_error and trx_set_detailed_error_from_file functions
  and a detailed_error field to trx_struct.
innobase/include/ut0mem.h:
  Add ut_strlcpy.
innobase/os/os0file.c:
  Add os_file_read_string.
innobase/row/row0ins.c:
  Add row_ins_set_detailed function and call it when needed.
  
  Adapt to changes in dict_print_info_on_foreign_key_in_create_format.
innobase/trx/trx0trx.c:
  Add trx_set_detailed_error and trx_set_detailed_error_from_file.
  
  Clear trx->detailed_error in trx_create.
innobase/ut/ut0mem.c:
  Add ut_strlcpy.
mysql-test/r/innodb.result:
  Add new tests, adapt existing ones whose output was changed.
mysql-test/t/innodb.test:
  Add new tests, adapt existing ones whose output was changed.
sql/ha_innodb.cc:
  Add get_error_message.
  
  Clear trx->detailed_error in start_stmt and external_lock.
sql/ha_innodb.h:
  Add get_error_message.
sql/handler.cc:
  Add special case code in print_error for HA_ERR_ROW_IS_REFERENCED and
  HA_ERR_NO_REFERENCED_ROW.
  
  Change SETMSG to point to new error messages.
sql/share/errmsg.txt:
  Add ER_ROW_IS_REFERENCED_2 and ER_NO_REFERENCED_ROW_2.

innobase/include/dict0dict.h

@@ -375,9 +375,10 @@ CREATE TABLE. */
 void
 dict_print_info_on_foreign_key_in_create_format(
 /*============================================*/
-	FILE*		file,	/* in: file where to print */
-	trx_t*		trx,	/* in: transaction */
-	dict_foreign_t*	foreign);/* in: foreign key constraint */
+	FILE*		file,		/* in: file where to print */
+	trx_t*		trx,		/* in: transaction */
+	dict_foreign_t*	foreign,	/* in: foreign key constraint */
+	ibool		add_newline);	/* in: whether to add a newline */
 /************************************************************************
 Displays the names of the index and the table. */
 void

innobase/include/os0file.h

@@ -432,6 +432,17 @@ os_file_read(
 				offset */
 	ulint		n);	/* in: number of bytes to read */	
 /***********************************************************************
+Rewind file to its start, read at most size - 1 bytes from it to str, and
+NUL-terminate str. All errors are silently ignored. This function is
+mostly meant to be used with temporary files. */
+
+void
+os_file_read_string(
+/*================*/
+	FILE*	file,	/* in: file to read from */
+	char*	str,	/* in: buffer where to read */
+	ulint	size);	/* in: size of buffer */
+/***********************************************************************
 Requests a synchronous positioned read operation. This function does not do
 any error handling. In case of error it returns FALSE. */
 

innobase/include/trx0trx.h

@@ -56,6 +56,22 @@ void
 trx_search_latch_release_if_reserved(
 /*=================================*/
         trx_t*     trx); /* in: transaction */
+/**********************************************************************
+Set detailed error message for the transaction. */
+void
+trx_set_detailed_error(
+/*===================*/
+	trx_t*	trx,	/* in: transaction struct */
+	char*	msg);	/* in: detailed error message */
+/*****************************************************************
+Set detailed error message for the transaction from a file. Note that the
+file is rewinded before reading from it. */
+
+void
+trx_set_detailed_error_from_file(
+/*=============================*/
+	trx_t*	trx,	/* in: transaction struct */
+	FILE*	file);	/* in: file to read message from */
 /********************************************************************
 Retrieves the error_info field from a trx. */
 
@@ -649,6 +665,9 @@ struct trx_struct{
 	trx_undo_arr_t*	undo_no_arr;	/* array of undo numbers of undo log
 					records which are currently processed
 					by a rollback operation */
+	/*------------------------------*/
+	char detailed_error[256];	/* detailed error message for last
+					error, or empty. */
 };
 
 #define TRX_MAX_N_THREADS	32	/* maximum number of concurrent

innobase/include/ut0mem.h

@@ -118,6 +118,18 @@ UNIV_INLINE
 int
 ut_strcmp(const void* str1, const void* str2);
 
+/**************************************************************************
+Copies up to size - 1 characters from the NUL-terminated string src to
+dst, NUL-terminating the result. Returns strlen(src), so truncation
+occurred if the return value >= size. */
+ulint
+ut_strlcpy(
+/*=======*/
+				/* out: strlen(src) */
+	char*		dst,	/* in: destination buffer */
+	const char*	src,	/* in: source buffer */
+	ulint		size);	/* in: size of destination buffer */
+
 /**************************************************************************
 Compute strlen(ut_strcpyq(str, q)). */
 UNIV_INLINE