MDL-52544 oracle: small tweaks

This commit just:

- Moves the null => '' to better place, restricting it to PHP >= 7.0
  (bug https://bugs.php.net/bug.php?id=72524)
- Adds a couple of notes here and there.
- Changes some small details to keep the file using the same coding.

diff --git a/lib/dml/oci_native_moodle_database.php b/lib/dml/oci_native_moodle_database.php
index d52483f..343663f 100644 (file)
--- a/lib/dml/oci_native_moodle_database.php
+++ b/lib/dml/oci_native_moodle_database.php
@@ -774,8 +774,6 @@ class oci_native_moodle_database extends moodle_database {
                 return ' ';
             } else if (is_bool($value)) {
                 return (int)$value;
-            } else if (is_null($value)) {
-                return '';
             } else {
                 return $value;
             }
@@ -788,8 +786,6 @@ class oci_native_moodle_database extends moodle_database {
                 return ' ';
             } else if (is_bool($value)) {
                 return (int)$value;
-            } else if (is_null($value)) {
-                return '';
             } else {
                 return $value;
             }
@@ -859,9 +855,6 @@ class oci_native_moodle_database extends moodle_database {
         } else if (gettype($value) == 'integer') {
             return '0'; // Transform 0 to '0' that evaluates the same for PHP
 
-        } else if (is_null($value)) {
-            return '';
-
         } else if ($value === '') {
             return ' '; // Transform '' to ' ' that DON'T EVALUATE THE SAME
                         // (we'll transform back again on get_records_XXX functions and others)!!
@@ -929,7 +922,7 @@ class oci_native_moodle_database extends moodle_database {
         return true;
     }
 
-    protected function bind_params($stmt, array & $params=null, $tablename=null, array & $descriptors = null) {
+    protected function bind_params($stmt, array &$params=null, $tablename=null, array &$descriptors = null) {
         if ($params) {
             $columns = array();
             if ($tablename) {
@@ -1015,6 +1008,12 @@ class oci_native_moodle_database extends moodle_database {
                     default: // Bind as CHAR (applying dirty hack)
                         // TODO: Optimise
                         $params[$key] = $this->oracle_dirty_hack($tablename, $columnname, $params[$key]);
+                        // Because of PHP7 bug (https://bugs.php.net/bug.php?id=72524) it seems that it's
+                        // impossible to bind NULL values in a reliable way, let's use empty string
+                        // instead in the mean time.
+                        if ($params[$key] === null && version_compare(PHP_VERSION, '7.0.0', '>=')) {
+                            $params[$key] = '';
+                        }
                         oci_bind_by_name($stmt, $key, $params[$key]);
                 }
             }
@@ -1024,7 +1023,10 @@ class oci_native_moodle_database extends moodle_database {
 
     protected function free_descriptors($descriptors) {
         foreach ($descriptors as $descriptor) {
+            // Because all descriptors used in the driver come from LOB::writeTemporary() calls
+            // we can safely close them here unconditionally.
             $descriptor->close();
+            // Free resources.
             oci_free_descriptor($descriptor);
         }
     }
@@ -1061,7 +1063,7 @@ class oci_native_moodle_database extends moodle_database {
         list($sql, $params) = $this->tweak_param_names($sql, $params);
         $this->query_start($sql, $params, SQL_QUERY_UPDATE);
         $stmt = $this->parse_query($sql);
-        $descriptors = [];
+        $descriptors = array();
         $this->bind_params($stmt, $params, null, $descriptors);
         $result = oci_execute($stmt, $this->commit_status);
         $this->free_descriptors($descriptors);
@@ -1127,7 +1129,7 @@ class oci_native_moodle_database extends moodle_database {
         list($rawsql, $params) = $this->tweak_param_names($rawsql, $params);
         $this->query_start($rawsql, $params, SQL_QUERY_SELECT);
         $stmt = $this->parse_query($rawsql);
-        $descriptors = [];
+        $descriptors = array();
         $this->bind_params($stmt, $params, null, $descriptors);
         $result = oci_execute($stmt, $this->commit_status);
         $this->free_descriptors($descriptors);
@@ -1164,7 +1166,7 @@ class oci_native_moodle_database extends moodle_database {
         list($rawsql, $params) = $this->tweak_param_names($rawsql, $params);
         $this->query_start($rawsql, $params, SQL_QUERY_SELECT);
         $stmt = $this->parse_query($rawsql);
-        $descriptors = [];
+        $descriptors = array();
         $this->bind_params($stmt, $params, null, $descriptors);
         $result = oci_execute($stmt, $this->commit_status);
         $this->free_descriptors($descriptors);
@@ -1205,7 +1207,7 @@ class oci_native_moodle_database extends moodle_database {
         list($sql, $params) = $this->tweak_param_names($sql, $params);
         $this->query_start($sql, $params, SQL_QUERY_SELECT);
         $stmt = $this->parse_query($sql);
-        $descriptors = [];
+        $descriptors = array();
         $this->bind_params($stmt, $params, null, $descriptors);
         $result = oci_execute($stmt, $this->commit_status);
         $this->free_descriptors($descriptors);
@@ -1274,7 +1276,7 @@ class oci_native_moodle_database extends moodle_database {
         if ($returning) {
             oci_bind_by_name($stmt, ":oracle_id", $id, 10, SQLT_INT);
         }
-        $descriptors = [];
+        $descriptors = array();
         $this->bind_params($stmt, $params, $table, $descriptors);
         $result = oci_execute($stmt, $this->commit_status);
         $this->free_descriptors($descriptors);
@@ -1389,7 +1391,7 @@ class oci_native_moodle_database extends moodle_database {
         // list($sql, $params) = $this->tweak_param_names($sql, $params);
         $this->query_start($sql, $params, SQL_QUERY_UPDATE);
         $stmt = $this->parse_query($sql);
-        $descriptors = [];
+        $descriptors = array();
         $this->bind_params($stmt, $params, $table, $descriptors);
         $result = oci_execute($stmt, $this->commit_status);
         $this->free_descriptors($descriptors);
@@ -1480,7 +1482,7 @@ class oci_native_moodle_database extends moodle_database {
         list($sql, $params) = $this->tweak_param_names($sql, $params);
         $this->query_start($sql, $params, SQL_QUERY_UPDATE);
         $stmt = $this->parse_query($sql);
-        $descriptors = [];
+        $descriptors = array();
         $this->bind_params($stmt, $params, $table, $descriptors);
         $result = oci_execute($stmt, $this->commit_status);
         $this->free_descriptors($descriptors);
@@ -1512,7 +1514,7 @@ class oci_native_moodle_database extends moodle_database {
         list($sql, $params) = $this->tweak_param_names($sql, $params);
         $this->query_start($sql, $params, SQL_QUERY_UPDATE);
         $stmt = $this->parse_query($sql);
-        $descriptors = [];
+        $descriptors = array();
         $this->bind_params($stmt, $params, null, $descriptors);
         $result = oci_execute($stmt, $this->commit_status);
         $this->free_descriptors($descriptors);