Correctly treat class names as case insensitive

package.xml

@@ -94,6 +94,7 @@
                     <file name="access_modifier_method_access_hook.phpt" role="test" />
                     <file name="access_modifier_property_access_hook.phpt" role="test" />
                     <file name="allow_overriding_before_overrided_methods_functions_are_defined.phpt" role="test" />
+                    <file name="case_insensitive_class_hook.phpt" role="test" />
                     <file name="case_insensitive_method_hook.phpt" role="test" />
                     <file name="closure_accessing_outside_variables.phpt" role="test" />
                     <file name="closure_set_inside_object_methods.phpt" role="test" />

src/ext/dispatch.c

@@ -43,14 +43,16 @@ static ddtrace_dispatch_t *find_method_dispatch(const zend_class_entry *class, z
     }
     HashTable *class_lookup = NULL;
 
+    // downcase the class name as they are case insensitive
 #if PHP_VERSION_ID < 70000
-    const char *class_name = NULL;
-    size_t class_name_length = 0;
-    class_name = class->name;
-    class_name_length = class->name_length;
+    size_t class_name_length = class->name_length;
+    char *class_name = zend_str_tolower_dup(class->name, class_name_length);
     class_lookup = zend_hash_str_find_ptr(DDTRACE_G(class_lookup), class_name, class_name_length);
+    efree(class_name);
 #else
-    class_lookup = zend_hash_find_ptr(DDTRACE_G(class_lookup), class->name);
+    zend_string *class_name = zend_string_tolower(class->name);
+    class_lookup = zend_hash_find_ptr(DDTRACE_G(class_lookup), class_name);
+    zend_string_release(class_name);
 #endif
 
     ddtrace_dispatch_t *dispatch = NULL;

src/ext/dispatch_setup.c

@@ -93,14 +93,25 @@ zend_bool ddtrace_trace(zval *class_name, zval *function_name, zval *callable, z
     HashTable *overridable_lookup = NULL;
     if (class_name && DDTRACE_G(class_lookup)) {
 #if PHP_VERSION_ID < 70000
+        // downcase the class name before lookup as class names are case insensitive.
+        zval *class_name_prev = class_name;
+        MAKE_STD_ZVAL(class_name);
+        ZVAL_STRING(class_name, Z_STRVAL_P(class_name_prev), 1);
+        ddtrace_downcase_zval(class_name);
         overridable_lookup =
             zend_hash_str_find_ptr(DDTRACE_G(class_lookup), Z_STRVAL_P(class_name), Z_STRLEN_P(class_name));
+        if (!overridable_lookup) {
+            overridable_lookup = ddtrace_new_class_lookup(class_name TSRMLS_CC);
+        }
+        zval_ptr_dtor(&class_name);
+        class_name = class_name_prev;
 #else
+        ddtrace_downcase_zval(class_name);
         overridable_lookup = zend_hash_find_ptr(DDTRACE_G(class_lookup), Z_STR_P(class_name));
-#endif
         if (!overridable_lookup) {
             overridable_lookup = ddtrace_new_class_lookup(class_name TSRMLS_CC);
         }
+#endif
     } else {
         if (DDTRACE_G(strict_mode)) {
             zend_function *function = NULL;

tests/ext/case_insensitive_class_hook.phpt

@@ -0,0 +1,22 @@
+--TEST--
+Check if for case insensitive class name support
+--FILE--
+<?php
+class Base {
+    public function method(){
+        echo __METHOD__ . PHP_EOL;
+    }
+}
+
+dd_trace("base", "method", function () {
+    echo "HOOK ";
+    return dd_trace_forward_call();
+});
+
+(new Base())->method();
+(new base())->method();
+
+?>
+--EXPECT--
+HOOK Base::method
+HOOK Base::method