db module support getting length of field value

lib_acl_cpp/changes.txt

@@ -1,5 +1,9 @@
 修改历史列表：
 
+570) 2019.5.27
+570.1) feature: db_handle/db_mysql/db_pgsql 支持获取字段值的长度
+-- by 孙良灿(1142263518)
+
 569) 2019.5.18
 569.1) compile: 增加宏编译选项 ACL_CLIENT_ONLY，当将 acl 库用于客户端模式时可以有效地
 减少编译库的大小

lib_acl_cpp/include/acl_cpp/db/db_handle.hpp

@@ -139,11 +139,25 @@ public:
 	 */
 	const char* field_string(const char* name) const;
 
+	/**
+	 * 从查询结果的记录行中取得对应下标的字符串类型的字段值长度
+	 * @param ifield {size_t} 下标值
+	 * @return {size_t}
+	 */
+	size_t field_length(size_t ifield) const;
+	/**
+	 * 从查询结果的记录行中取得字段名的字符串类型的字段值长度
+	 * @param name {const char*} 下标值
+	 * @return {size_t}
+	 */
+	size_t field_length(const char* name) const;
+
 	/**
 	 * 向记录行添加一个字段值，添加字段值的顺序应该与字段名的顺序一致
 	 * @param value {const char*} 该行记录的某个字段值
+	 * @param len {size_t} value 数据长度
 	 */
-	void push_back(const char* value);
+	void push_back(const char* value, size_t len);
 
 	/**
 	 * 行记录中字段值的个数
@@ -162,6 +176,9 @@ private:
 
 	// 数据结果行的字段集合
 	std::vector<const char*> values_;
+
+	// 数据结果行字段长度集合
+	std::vector<size_t> lengths_;
 };
 
 /**

lib_acl_cpp/src/db/db_handle.cpp

@@ -158,9 +158,46 @@ const char* db_row::field_string(const char* name) const
 		return ptr;
 }
 
-void db_row::push_back(const char* value)
+size_t db_row::field_length(size_t ifield) const
+{
+	if (ifield >= lengths_.size()) {
+		logger_error("ifield(%d) invalid, lengths_.size: %d",
+			(int) ifield, (int) lengths_.size());
+		return NULL;
+	}
+
+	return lengths_[ifield];
+}
+
+size_t db_row::field_length(const char* name) const
+{
+	size_t   i, n = names_.size();
+
+	// 必须保证表中字段名的个数与行记录的值的个数相等
+	if (lengths_.size() != n) {
+		logger_error("invalid result, names=%d, lengths_=%d",
+			(int) n, (int) lengths_.size());
+		return NULL;
+	}
+
+	// 通过扫描字段名找出字段值的下标位置
+	for (i = 0; i < n; i++) {
+		if (strcasecmp(name, names_[i]) == 0)
+			break;
+	}
+	if (i == n) {
+		logger_error("cloumn not exist, name: %s", name);
+		return NULL;
+	}
+
+	// 直接返回相应下标的字段值
+	return lengths_[i];
+}
+
+void db_row::push_back(const char* value, size_t len)
 {
 	values_.push_back(value);
+	lengths_.push_back(len);
 }
 
 size_t db_row::length(void) const

lib_acl_cpp/src/db/db_mysql.cpp

@@ -41,6 +41,7 @@ typedef const char* (STDCALL *mysql_error_fn)(MYSQL*);
 typedef int (STDCALL *mysql_query_fn)(MYSQL*, const char*);
 typedef unsigned int (STDCALL *mysql_num_fields_fn)(MYSQL_RES*);
 typedef MYSQL_FIELD* (STDCALL *mysql_fetch_fields_fn)(MYSQL_RES*);
+typedef unsigned long* (STDCALL *mysql_fetch_lengths_fn)(MYSQL_RES*);
 typedef MYSQL_ROW (STDCALL *mysql_fetch_row_fn)(MYSQL_RES*);
 typedef MYSQL_RES* (STDCALL *mysql_store_result_fn)(MYSQL*);
 typedef my_ulonglong (STDCALL *mysql_num_rows_fn)(MYSQL_RES*);
@@ -65,6 +66,7 @@ static mysql_error_fn __mysql_error = NULL;
 static mysql_query_fn __mysql_query = NULL;
 static mysql_num_fields_fn __mysql_num_fields = NULL;
 static mysql_fetch_fields_fn __mysql_fetch_fields = NULL;
+static mysql_fetch_lengths_fn __mysql_fetch_lengths = NULL;
 static mysql_fetch_row_fn __mysql_fetch_row = NULL;
 static mysql_store_result_fn __mysql_store_result = NULL;
 static mysql_num_rows_fn __mysql_num_rows = NULL;
@@ -207,6 +209,12 @@ static void __mysql_dll_load(void)
 		logger_fatal("load mysql_fetch_fields from %s error: %s",
 			path, acl_dlerror());
 
+	__mysql_fetch_lengths = (mysql_fetch_lengths_fn)
+		acl_dlsym(__mysql_dll, "mysql_fetch_lengths");
+	if (__mysql_fetch_lengths == NULL)
+		logger_fatal("load mysql_fetch_lengths from %s error: %s",
+			path, acl_dlerror());
+
 	__mysql_fetch_row = (mysql_fetch_row_fn)
 		acl_dlsym(__mysql_dll, "mysql_fetch_row");
 	if (__mysql_fetch_row == NULL)
@@ -291,6 +299,7 @@ static void __mysql_dll_load(void)
 #  define  __mysql_query mysql_query
 #  define  __mysql_num_fields mysql_num_fields
 #  define  __mysql_fetch_fields mysql_fetch_fields
+#  define  __mysql_fetch_lengths mysql_fetch_lengths
 #  define  __mysql_fetch_row mysql_fetch_row
 #  define  __mysql_store_result mysql_store_result
 #  define  __mysql_num_rows mysql_num_rows
@@ -339,9 +348,12 @@ static void mysql_rows_save(MYSQL_RES* my_res, db_rows& result)
 		MYSQL_ROW my_row = __mysql_fetch_row(my_res);
 		if (my_row == NULL)
 			break;
+		unsigned long *my_lengths = __mysql_fetch_lengths(my_res);
+		if (my_lengths == NULL)
+			break;
 		db_row* row = NEW db_row(result.names_);
 		for (int j = 0; j < ncolumn; j++)
-			row->push_back(my_row[j]);
+			row->push_back(my_row[j], (size_t) my_lengths[j]);
 		result.rows_.push_back(row);
 	}
 

lib_acl_cpp/src/db/db_pgsql.cpp

@@ -36,6 +36,7 @@ typedef int   (*PQnfields_fn)(const PGresult *res);
 typedef char *(*PQfname_fn)(const PGresult *res, int field_num);
 typedef int   (*PQntuples_fn)(const PGresult *res);
 typedef char *(*PQgetvalue_fn)(const PGresult *res, int tup_num, int field_num);
+typedef int   (*PQgetlength_fn)(const PGresult *res, int tup_num, int field_num);
 typedef char *(*PQcmdTuples_fn)(PGresult *res);
 
 static PQconnectdb_fn __dbconnect = NULL;
@@ -49,6 +50,7 @@ static PQnfields_fn __dbnfields = NULL;
 static PQfname_fn __dbfname = NULL;
 static PQntuples_fn __dbntuples = NULL;
 static PQgetvalue_fn __dbget_value = NULL;
+static PQgetlength_fn __dbget_length = NULL;
 static PQcmdTuples_fn __dbcmd_tuples = NULL;
 
 static acl_pthread_once_t __pgsql_once = ACL_PTHREAD_ONCE_INIT;
@@ -152,6 +154,11 @@ static void __pgsql_dll_load(void)
 		logger_fatal("load PQgetvalue from %s error %s",
 			path, acl_dlerror());
 
+	__dbget_length = (PQgetlength_fn) acl_dlsym(__pgsql_dll, "PQgetlength");
+	if (__dbget_length == NULL)
+		logger_fatal("load PQgetlength from %s error %s",
+			path, acl_dlerror());
+
 	__dbcmd_tuples = (PQcmdTuples_fn) acl_dlsym(__pgsql_dll, "PQcmdTuples");
 	if (__dbcmd_tuples == NULL)
 		logger_fatal("load PQcmdTuples from %s error %s",
@@ -173,6 +180,7 @@ static void __pgsql_dll_load(void)
 #  define __dbfname PQfname
 #  define __dbntuples PQntuples
 #  define __dbget_value PQgetvalue
+#  define __dbget_length PQgetlength
 #  define __dbcmd_tuples PQcmdTuples
 # endif
 
@@ -209,7 +217,11 @@ static void pgsql_rows_save(PGresult* res, db_rows& result)
 	{
 		db_row* row = NEW db_row(result.names_);
 		for (int j = 0; j < ncolumn; j++)
-			row->push_back(__dbget_value(res, i, j));
+		{
+			char* value = __dbget_value(res, i, j);
+			int len = __dbget_length(res, i, j);
+			row->push_back(value, (size_t) len);
+		}
 		result.rows_.push_back(row);
 	}
 

lib_acl_cpp/src/db/db_sqlite.cpp

@@ -290,7 +290,9 @@ static void sqlite_rows_save(char** results, int nrow,
 	for (int i = 0; i < nrow; i++) {
 		db_row* row = NEW db_row(result.names_);
 		for (int j = 0; j < ncolumn; j++) {
-			row->push_back(results[n++]);
+			const char* value = results[n++];
+			size_t len = strlen(value);
+			row->push_back(value, len);
 		}
 		result.rows_.push_back(row);
 	}

lib_acl_cpp/src/db/sqlite_cursor.cpp

@@ -50,19 +50,19 @@ void sqlite_cursor::add_column_value(long long n)
 {
 	char* buf = (char*) dbuf_->dbuf_alloc(INT4_STR_SIZE + 1);
 	safe_snprintf(buf, INT4_STR_SIZE + 1, "%lld", n);
-	row_->push_back(buf);
+	row_->push_back(buf, strlen(buf));
 }
 
 void sqlite_cursor::add_column_value(double n)
 {
 	char* buf = (char*) dbuf_->dbuf_alloc(INT4_STR_SIZE + 1);
 	safe_snprintf(buf, INT4_STR_SIZE + 1, "%.4f", n);
-	row_->push_back(buf);
+	row_->push_back(buf, strlen(buf));
 }
 
 void sqlite_cursor::add_column_value(const char* s)
 {
-	row_->push_back(s);
+	row_->push_back(s, strlen(s));
 }
 
 } // namespace acl