Replace get_value_as_string() by get() function returning string_view

This way we don't need to initialize a std::string in all cases.

Author: joto

src/pgsql-capabilities.cpp

@@ -48,7 +48,7 @@ static void init_set_from_query(std::set<std::string> *set,
         PGRES_TUPLES_OK,
         "SELECT {} FROM {} WHERE {}"_format(column, table, condition));
     for (int i = 0; i < res.num_tuples(); ++i) {
-        set->insert(res.get_value_as_string(i, 0));
+        set->emplace(res.get(i, 0));
     }
 }
 
@@ -59,8 +59,7 @@ static void init_settings(pg_conn_t const &db_connection)
         PGRES_TUPLES_OK, "SELECT name, setting FROM pg_settings");
 
     for (int i = 0; i < res.num_tuples(); ++i) {
-        capabilities().settings.emplace(res.get_value_as_string(i, 0),
-                                        res.get_value_as_string(i, 1));
+        capabilities().settings.emplace(res.get(i, 0), res.get(i, 1));
     }
 }
 
@@ -74,7 +73,7 @@ static void init_database_name(pg_conn_t const &db_connection)
             "Database error: Can not access database name."};
     }
 
-    capabilities().database_name = res.get_value_as_string(0, 0);
+    capabilities().database_name = res.get(0, 0);
 }
 
 static void init_postgis_version(pg_conn_t const &db_connection)
@@ -91,8 +90,8 @@ static void init_postgis_version(pg_conn_t const &db_connection)
                 capabilities().database_name)};
     }
 
-    capabilities().postgis = {std::stoi(res.get_value_as_string(0, 0)),
-                              std::stoi(res.get_value_as_string(1, 0))};
+    capabilities().postgis = {std::stoi(std::string{res.get(0, 0)}),
+                              std::stoi(std::string{res.get(1, 0)})};
 }
 
 void init_database_capabilities(pg_conn_t const &db_connection)

src/pgsql.hpp

@@ -93,13 +93,12 @@ class pg_result_t
     }
 
     /**
-     * Create a std::string with the value of the field at (row, col). This
-     * does the correct thing for binary data.
+     * Return a std::string_view with the value of the field at (row, col).
      */
-    std::string get_value_as_string(int row, int col) const noexcept
+    std::string_view get(int row, int col) const noexcept
     {
-        return std::string(get_value(row, col),
-                           (std::size_t)get_length(row, col));
+        return {get_value(row, col),
+                static_cast<std::size_t>(get_length(row, col))};
     }
 
     /**

tests/common-pg.hpp

@@ -43,7 +43,7 @@ class conn_t : public pg_conn_t
     {
         pg_result_t const res = query(PGRES_TUPLES_OK, cmd);
         REQUIRE(res.num_tuples() == 1);
-        return res.get_value_as_string(0, 0);
+        return std::string{res.get(0, 0)};
     }
 
     int result_as_int(std::string const &cmd) const

tests/test-db-copy-mgr.cpp

@@ -235,7 +235,7 @@ TEST_CASE("copy_mgr_t")
         auto const res = conn.query(PGRES_TUPLES_OK,
                                     "SELECT t FROM test_copy_mgr ORDER BY id");
         CHECK(res.num_tuples() == 2);
-        CHECK(res.get_value_as_string(0, 0) == "good");
-        CHECK(res.get_value_as_string(1, 0) == "better");
+        CHECK(res.get(0, 0) == "good");
+        CHECK(res.get(1, 0) == "better");
     }
 }

tests/test-pgsql.cpp

@@ -41,7 +41,7 @@ TEST_CASE("query with SELECT should work")
     REQUIRE(result.status() == PGRES_TUPLES_OK);
     REQUIRE(result.num_fields() == 1);
     REQUIRE(result.num_tuples() == 1);
-    REQUIRE(result.get_value_as_string(0, 0) == "42");
+    REQUIRE(result.get(0, 0) == "42");
 }
 
 TEST_CASE("query with invalid SQL should fail")
@@ -65,7 +65,7 @@ TEST_CASE("exec_prepared without parameters should work")
     REQUIRE(result.status() == PGRES_TUPLES_OK);
     REQUIRE(result.num_fields() == 1);
     REQUIRE(result.num_tuples() == 1);
-    REQUIRE(result.get_value_as_string(0, 0) == "42");
+    REQUIRE(result.get(0, 0) == "42");
 }
 
 TEST_CASE("exec_prepared with single string parameters should work")
@@ -77,7 +77,7 @@ TEST_CASE("exec_prepared with single string parameters should work")
     REQUIRE(result.status() == PGRES_TUPLES_OK);
     REQUIRE(result.num_fields() == 1);
     REQUIRE(result.num_tuples() == 1);
-    REQUIRE(result.get_value_as_string(0, 0) == "17");
+    REQUIRE(result.get(0, 0) == "17");
 }
 
 TEST_CASE("exec_prepared with string parameters should work")
@@ -89,7 +89,7 @@ TEST_CASE("exec_prepared with string parameters should work")
     REQUIRE(result.status() == PGRES_TUPLES_OK);
     REQUIRE(result.num_fields() == 1);
     REQUIRE(result.num_tuples() == 1);
-    REQUIRE(result.get_value_as_string(0, 0) == "6");
+    REQUIRE(result.get(0, 0) == "6");
 }
 
 TEST_CASE("exec_prepared with non-string parameters should work")
@@ -101,5 +101,5 @@ TEST_CASE("exec_prepared with non-string parameters should work")
     REQUIRE(result.status() == PGRES_TUPLES_OK);
     REQUIRE(result.num_fields() == 1);
     REQUIRE(result.num_tuples() == 1);
-    REQUIRE(result.get_value_as_string(0, 0) == "6");
+    REQUIRE(result.get(0, 0) == "6");
 }