Improve data caching with datetime objects

source/pdo_sqlsrv/pdo_stmt.cpp

@@ -220,7 +220,7 @@ void meta_data_free( _Inout_ field_meta_data* meta )
     sqlsrv_free( meta );
 }
 
-zval convert_to_zval( _In_ SQLSRV_PHPTYPE sqlsrv_php_type, _Inout_ void** in_val, _In_opt_ SQLLEN field_len )
+zval convert_to_zval(_Inout_ sqlsrv_stmt* stmt, _In_ SQLSRV_PHPTYPE sqlsrv_php_type, _Inout_ void** in_val, _In_opt_ SQLLEN field_len )
 {
     zval out_zval;
     ZVAL_UNDEF(&out_zval);
@@ -264,15 +264,8 @@ zval convert_to_zval( _In_ SQLSRV_PHPTYPE sqlsrv_php_type, _Inout_ void** in_val
         break;
     }
     case SQLSRV_PHPTYPE_DATETIME:
-        if (*in_val == NULL) {
-
-            ZVAL_NULL(&out_zval);
-        }
-        else {
-
-            out_zval = *(reinterpret_cast<zval*>(*in_val));
-            sqlsrv_free(*in_val);
-        }
+        convert_datetime_string_to_zval(stmt, static_cast<char*>(*in_val), field_len, out_zval);
+        sqlsrv_free(*in_val);
         break;
     case SQLSRV_PHPTYPE_NULL:
         ZVAL_NULL(&out_zval);
@@ -833,11 +826,11 @@ int pdo_sqlsrv_stmt_get_col_data( _Inout_ pdo_stmt_t *stmt, _In_ int colno,
         core_sqlsrv_get_field( driver_stmt, colno, sqlsrv_php_type, false, *(reinterpret_cast<void**>(ptr)),
                                reinterpret_cast<SQLLEN*>( len ), true, &sqlsrv_phptype_out TSRMLS_CC );
 
-        if ( ptr ) {
-            zval* zval_ptr = reinterpret_cast<zval*>( sqlsrv_malloc( sizeof( zval )));
-            *zval_ptr = convert_to_zval( sqlsrv_phptype_out, reinterpret_cast<void**>( ptr ), *len );
-            *ptr = reinterpret_cast<char*>( zval_ptr );
-            *len = sizeof( zval );
+        if (ptr) {
+            zval* zval_ptr = reinterpret_cast<zval*>(sqlsrv_malloc(sizeof(zval)));
+            *zval_ptr = convert_to_zval(driver_stmt, sqlsrv_phptype_out, reinterpret_cast<void**>(ptr), *len);
+            *ptr = reinterpret_cast<char*>(zval_ptr);
+            *len = sizeof(zval);
         }
 
         return 1;        

source/shared/core_sqlsrv.h

@@ -1810,6 +1810,8 @@ bool validate_string( _In_ char* string, _In_ SQLLEN& len);
 bool convert_string_from_utf16( _In_ SQLSRV_ENCODING encoding, _In_reads_bytes_(cchInLen) const SQLWCHAR* inString, _In_ SQLINTEGER cchInLen, _Inout_updates_bytes_(cchOutLen) char** outString, _Out_ SQLLEN& cchOutLen );
 SQLWCHAR* utf16_string_from_mbcs_string( _In_ SQLSRV_ENCODING php_encoding, _In_reads_bytes_(mbcs_len) const char* mbcs_string, _In_ unsigned int mbcs_len, _Out_ unsigned int* utf16_len, bool use_strict_conversion = false );
 
+void convert_datetime_string_to_zval(_Inout_ sqlsrv_stmt* stmt, _In_opt_ char* input, _In_ SQLLEN length, _Inout_ zval& out_zval);
+
 //*********************************************************************************************************************************
 // Error handling routines and Predefined Errors
 //*********************************************************************************************************************************

source/shared/core_stmt.cpp

@@ -1867,54 +1867,36 @@ void core_get_field_common( _Inout_ sqlsrv_stmt* stmt, _In_ SQLUSMALLINT field_i
             break;
         }
 
-        // get the date as a string (http://msdn2.microsoft.com/en-us/library/ms712387(VS.85).aspx) and
-        // convert it to a DateTime object and return the created object
+        // Reference: https://docs.microsoft.com/sql/odbc/reference/appendixes/sql-to-c-timestamp
+        // Retrieve the datetime data as a string, which may be cached for later use.
+        // The string is converted to a DateTime object only when it is required to 
+        // be returned as a zval.
         case SQLSRV_PHPTYPE_DATETIME:
         {
-            char field_value_temp[MAX_DATETIME_STRING_LEN] = {'\0'};
-            zval params[1];
-            zval field_value_temp_z;
-            zval function_z;
+            char* field_value_temp = NULL;
+            SQLLEN field_len_temp = 0;
 
-            ZVAL_UNDEF( &field_value_temp_z );
-            ZVAL_UNDEF( &function_z );
-            ZVAL_UNDEF( params );
+            field_value_temp = static_cast<char*>(sqlsrv_malloc(MAX_DATETIME_STRING_LEN));
+            memset(field_value_temp, '\0', MAX_DATETIME_STRING_LEN);
 
-            SQLRETURN r = stmt->current_results->get_data( field_index + 1, SQL_C_CHAR, field_value_temp,
-                                                           MAX_DATETIME_STRING_LEN, field_len, true TSRMLS_CC );
+            SQLRETURN r = stmt->current_results->get_data(field_index + 1, SQL_C_CHAR, field_value_temp, MAX_DATETIME_STRING_LEN, &field_len_temp, true TSRMLS_CC);
 
-            CHECK_CUSTOM_ERROR(( r == SQL_NO_DATA ), stmt, SQLSRV_ERROR_NO_DATA, field_index ) {
-                throw core::CoreException();
+            if (r == SQL_NO_DATA || field_len_temp == SQL_NULL_DATA) {
+                sqlsrv_free(field_value_temp);
+                field_value_temp = NULL;
+                field_len_temp = 0;
             }
 
-            zval_auto_ptr return_value_z;
-            return_value_z = ( zval * )sqlsrv_malloc( sizeof( zval ));
-            ZVAL_UNDEF( return_value_z );
-
-            if( *field_len == SQL_NULL_DATA ) {
-                ZVAL_NULL( return_value_z );
-                field_value = reinterpret_cast<void*>( return_value_z.get());
-                return_value_z.transferred();
-                break;
+            CHECK_CUSTOM_ERROR((r == SQL_NO_DATA), stmt, SQLSRV_ERROR_NO_DATA, field_index) {
+                throw core::CoreException();
             }
 
-            // Convert the string date to a DateTime object
-            core::sqlsrv_zval_stringl( &field_value_temp_z, field_value_temp, *field_len );
-            core::sqlsrv_zval_stringl( &function_z, "date_create", sizeof("date_create") - 1 );
-            params[0] = field_value_temp_z;
-
-            if( call_user_function( EG( function_table ), NULL, &function_z, return_value_z, 1,
-                params TSRMLS_CC ) == FAILURE) {
-                THROW_CORE_ERROR(stmt, SQLSRV_ERROR_DATETIME_CONVERSION_FAILED);
-            }
+            field_value = field_value_temp;
+            *field_len = field_len_temp;
 
-            field_value = reinterpret_cast<void*>( return_value_z.get());
-            return_value_z.transferred();
-            zend_string_free( Z_STR( field_value_temp_z ));
-            zend_string_free( Z_STR( function_z ));
             break;
         }
-
+        
         // create a stream wrapper around the field and return that object to the PHP script.  calls to fread
         // on the stream will result in calls to SQLGetData.  This is handled in stream.cpp.  See that file
         // for how these fields are used.

source/shared/core_util.cpp

@@ -189,6 +189,40 @@ SQLWCHAR* utf16_string_from_mbcs_string( _In_ SQLSRV_ENCODING php_encoding, _In_
     return utf16_string;
 }
 
+// Converts an input (assuming a datetime string) to a zval containing a PHP DateTime object. 
+// If the input is null, this simply returns a NULL zval. If anything wrong occurs during conversion,
+// an exception will be thrown.
+void convert_datetime_string_to_zval(_Inout_ sqlsrv_stmt* stmt, _In_opt_ char* input, _In_ SQLLEN length, _Inout_ zval& out_zval)
+{
+    if (input == NULL) {
+        ZVAL_NULL(&out_zval);
+        return;
+    }
+
+    zval params[1];
+    zval value_temp_z;
+    zval function_z;
+
+    // Initialize all zval variables
+    ZVAL_UNDEF(&out_zval);
+    ZVAL_UNDEF(&value_temp_z);
+    ZVAL_UNDEF(&function_z);
+    ZVAL_UNDEF(params);
+
+    // Convert the datetime string to a PHP DateTime object
+    core::sqlsrv_zval_stringl(&value_temp_z, input, length);
+    core::sqlsrv_zval_stringl(&function_z, "date_create", sizeof("date_create") - 1);
+    params[0] = value_temp_z;
+
+    if (call_user_function(EG(function_table), NULL, &function_z, &out_zval, 1,
+                           params TSRMLS_CC) == FAILURE) {
+        THROW_CORE_ERROR(stmt, SQLSRV_ERROR_DATETIME_CONVERSION_FAILED);
+    }
+
+    zend_string_free(Z_STR(value_temp_z));
+    zend_string_free(Z_STR(function_z));
+}
+
 // call to retrieve an error from ODBC.  This uses SQLGetDiagRec, so the
 // errno is 1 based.  It returns it as an array with 3 members:
 // 1/SQLSTATE) sqlstate

source/sqlsrv/stmt.cpp

@@ -1513,11 +1513,11 @@ void convert_to_zval( _Inout_ sqlsrv_stmt* stmt, _In_ SQLSRV_PHPTYPE sqlsrv_php_
 		Z_TRY_ADDREF( out_zval );
 		break;
 	}
-	case SQLSRV_PHPTYPE_DATETIME:
-	{
-		out_zval = *( static_cast<zval*>( in_val ));
-		break;
-	}
+    case SQLSRV_PHPTYPE_DATETIME:
+    {
+        convert_datetime_string_to_zval(stmt, static_cast<char*>(in_val), field_len, out_zval);
+        break;
+    }
 
 	case SQLSRV_PHPTYPE_NULL:
 		ZVAL_NULL(&out_zval);

test/functional/pdo_sqlsrv/pdo_fetch_datetime_time_as_objects.phpt

@@ -70,6 +70,33 @@ function checkColumnDTValue($index, $column, $values, $dtObj)
     } 
 }
 
+function randomColumns($conn, $query, $columns, $values)
+{
+    $conn->setAttribute(PDO::SQLSRV_ATTR_FETCHES_DATETIME_TYPE, true);
+    $stmt = $conn->prepare($query);
+
+    // Fetch a random column to trigger caching
+    $lastCol = count($columns) - 1;
+    $col = rand(0, $lastCol);
+    $stmt->execute();
+    $dtObj = $stmt->fetchColumn($col);
+    checkColumnDTValue($col, $columns[$col], $values, $dtObj);
+
+    // Similarly, fetch another column
+    $col = (++$col) % count($columns);
+    $stmt->execute();
+    $dtObj = $stmt->fetchColumn($col);
+    checkColumnDTValue($col, $columns[$col], $values, $dtObj);
+
+    // Now fetch all columns in a backward order
+    $i = $lastCol;
+    do {
+        $stmt->execute();
+        $dtObj = $stmt->fetchColumn($i);
+        checkColumnDTValue($i, $columns[$i], $values, $dtObj);
+    } while (--$i >= 0);
+}
+
 function runTest($conn, $query, $columns, $values, $useBuffer = false)
 {
     // fetch the date time values as strings or date time objects
@@ -103,7 +130,7 @@ function runTest($conn, $query, $columns, $values, $useBuffer = false)
     $stmt->execute();
     $row = $stmt->fetch(PDO::FETCH_BOTH);
     checkDTObjectValues($row, $columns, $values, PDO::FETCH_BOTH);
-    
+
     // ATTR_STRINGIFY_FETCHES should have no effect when fetching date time objects 
     // Setting it to true only converts numeric values to strings when fetching
     // See http://www.php.net/manual/en/pdo.setattribute.php for details
@@ -164,7 +191,6 @@ function runTest($conn, $query, $columns, $values, $useBuffer = false)
     // last test: set statement attribute fetch_datetime on with no change to 
     // prepared statement -- expected datetime objects to be returned
     $stmt->setAttribute(PDO::SQLSRV_ATTR_FETCHES_DATETIME_TYPE, true);
-    $stmt->execute();
     $i = 0;
     do {
         $stmt->execute();
@@ -234,8 +260,9 @@ try {
 
     $query = "SELECT * FROM $tableName";
 
-    runTest($conn, $query, $columns, $values);
-    runTest($conn, $query, $columns, $values, true);
+    runtest($conn, $query, $columns, $values);
+    runtest($conn, $query, $columns, $values, true);
+    randomColumns($conn, $query, $columns, $values);
 
     dropTable($conn, $tableName);
 

test/functional/pdo_sqlsrv/pdo_fetch_datetime_time_nulls.phpt

@@ -110,7 +110,6 @@ function runTest($conn, $query, $columns, $useBuffer = false)
     // last test: set statement attribute fetch_datetime on with no change to 
     // prepared statement -- expected datetime objects to be returned
     $stmt->setAttribute(PDO::SQLSRV_ATTR_FETCHES_DATETIME_TYPE, true);
-    $stmt->execute();
     $i = 0;
     do {
         $stmt->execute();