Add refcounting mechanism to xdebug_str to avoid copies

derickr · Sep 10, 2024 · 4198eb5 · 4198eb5
1 parent 12adc63
commit 4198eb5
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Showing 5 changed files with 41 additions and 14 deletions.
diff --git a/src/develop/stack.c b/src/develop/stack.c
@@ -2,7 +2,7 @@
    +----------------------------------------------------------------------+
    | Xdebug                                                               |
    +----------------------------------------------------------------------+
-   | Copyright (c) 2002-2023 Derick Rethans                               |
+   | Copyright (c) 2002-2024 Derick Rethans                               |
    +----------------------------------------------------------------------+
    | This source file is subject to version 1.01 of the Xdebug license,   |
    | that is bundled with this package in the file LICENSE, and is        |
@@ -1273,7 +1273,7 @@ void xdebug_develop_throw_exception_hook(zend_object *exception, zval *file, zva
 			xdebug_append_error_footer(&displ_tmp_str, PG(html_errors));
 
 			php_printf("%s", displ_tmp_str.d);
-			xdebug_str_dtor(displ_tmp_str);
+			xdebug_str_destroy(&displ_tmp_str);
 		}
 	}
 }

diff --git a/src/lib/str.c b/src/lib/str.c
@@ -184,6 +184,8 @@ xdebug_str *xdebug_str_new(void)
 	tmp->l = 0;
 	tmp->a = 0;
 	tmp->d = NULL;
+	tmp->rc = 1;
+	tmp->is_static = false;
 
 	return tmp;
 }
@@ -206,9 +208,11 @@ xdebug_str *xdebug_str_create_from_char(char *c)
 	return xdebug_str_create(c, strlen(c));
 }
 
-xdebug_str *xdebug_str_copy(xdebug_str *orig)
+xdebug_str *xdebug_str_clone(xdebug_str *orig)
 {
-	xdebug_str *tmp = xdebug_str_new();
+	xdebug_str *tmp;
+
+	tmp = xdebug_str_new();
 
 	tmp->l = tmp->a = orig->l;
 	tmp->a++;
@@ -219,16 +223,37 @@ xdebug_str *xdebug_str_copy(xdebug_str *orig)
 	return tmp;
 }
 
-void xdebug_str_destroy(xdebug_str *s)
+xdebug_str *xdebug_str_copy(xdebug_str *orig)
+{
+	orig->rc++;
+
+	return orig;
+}
+
+static void xdebug_str_free_storage(xdebug_str *s)
 {
 	if (s->d) {
 		xdfree(s->d);
 	}
 }
 
+void xdebug_str_destroy(xdebug_str *s)
+{
+	assert(s->is_static);
+	xdebug_str_free_storage(s);
+}
+
 void xdebug_str_free(xdebug_str *s)
 {
-	xdebug_str_destroy(s);
+	assert(!s->is_static);
+
+	s->rc--;
+
+	if (s->rc > 0) {
+		return;
+	}
+
+	xdebug_str_free_storage(s);
 	xdfree(s);
 }
 

diff --git a/src/lib/str.h b/src/lib/str.h
@@ -2,7 +2,7 @@
    +----------------------------------------------------------------------+
    | Xdebug                                                               |
    +----------------------------------------------------------------------+
-   | Copyright (c) 2002-2020 Derick Rethans                               |
+   | Copyright (c) 2002-2024 Derick Rethans                               |
    +----------------------------------------------------------------------+
    | This source file is subject to version 1.01 of the Xdebug license,   |
    | that is bundled with this package in the file LICENSE, and is        |
@@ -23,16 +23,17 @@
 
 #include "mm.h"
 
-#define XDEBUG_STR_INITIALIZER { 0, 0, NULL }
+#define XDEBUG_STR_INITIALIZER { 0, 0, NULL, 0, true }
 #define XDEBUG_STR_PREALLOC 1024
-#define xdebug_str_dtor(str)     xdfree(str.d)
 
 #define XDEBUG_STR_WRAP_CHAR(v) (&((xdebug_str){strlen(v), strlen(v)+1, ((char*)(v))}))
 
 typedef struct xdebug_str {
 	size_t l;
 	size_t a;
 	char *d;
+	size_t rc; // refcount
+	bool   is_static; // not an allocated xdebug_str
 } xdebug_str;
 
 void xdebug_str_add(xdebug_str *xs, const char *str, int f);
@@ -52,7 +53,8 @@ xdebug_str *xdebug_str_new(void);
 xdebug_str *xdebug_str_create_from_char(char *c);
 #define xdebug_str_create_from_const_char(c) xdebug_str_create_from_char((char*) (c))
 xdebug_str *xdebug_str_create(const char *c, size_t len);
-xdebug_str *xdebug_str_copy(xdebug_str *orig);
+xdebug_str *xdebug_str_copy(xdebug_str *orig); // uses refcounting
+xdebug_str *xdebug_str_clone(xdebug_str *orig); // new allocation + copying data
 void xdebug_str_destroy(xdebug_str *s);
 void xdebug_str_free(xdebug_str *s);
 

diff --git a/src/lib/var_export_xml.c b/src/lib/var_export_xml.c
@@ -798,8 +798,8 @@ xdebug_xml_node* xdebug_get_zval_value_xml_node_ex(xdebug_str *name, zval *val,
 				xdebug_str_add_literal(&tmp_formatted_name, "::");
 				xdebug_str_add_str(&tmp_formatted_name, name);
 
-				short_name = xdebug_str_copy(&tmp_formatted_name);
-				full_name =  xdebug_str_copy(&tmp_formatted_name);
+				short_name = xdebug_str_clone(&tmp_formatted_name);
+				full_name =  xdebug_str_clone(&tmp_formatted_name);
 
 				xdebug_str_destroy(&tmp_formatted_name);
 			} break;

diff --git a/src/profiler/profiler.c b/src/profiler/profiler.c
@@ -2,7 +2,7 @@
    +----------------------------------------------------------------------+
    | Xdebug                                                               |
    +----------------------------------------------------------------------+
-   | Copyright (c) 2002-2023 Derick Rethans                               |
+   | Copyright (c) 2002-2024 Derick Rethans                               |
    +----------------------------------------------------------------------+
    | This source file is subject to version 1.01 of the Xdebug license,   |
    | that is bundled with this package in the file LICENSE, and is        |
@@ -528,7 +528,7 @@ void xdebug_profiler_function_end(function_stack_entry *fse)
 	xdebug_str_addc(&file_buffer, '\n');
 
 	xdebug_file_write(file_buffer.d, sizeof(char), file_buffer.l, &XG_PROF(profile_file));
-	xdebug_str_dtor(file_buffer);
+	xdebug_str_destroy(&file_buffer);
 }
 
 void xdebug_profiler_free_function_details(function_stack_entry *fse)