src/ecmascript/spidermonkey-shared.c

   1 /** SpiderMonkey support for both user scripts and web scripts.
   2  * @file */
   3
   4 #ifdef HAVE_CONFIG_H
   5 #include "config.h"
   6 #endif
   7
   8 #include "elinks.h"
   9
  10 #include "ecmascript/spidermonkey-shared.h"
  11
  12 /** A shared runtime used for both user scripts (scripting/smjs/) and
  13  * scripts on web pages (ecmascript/spidermonkey/).
  14  *
  15  * SpiderMonkey has bugs that corrupt memory when multiple JSRuntimes
  16  * are used: https://bugzilla.mozilla.org/show_bug.cgi?id=378918 and
  17  * perhaps others.  */
  18 JSRuntime *spidermonkey_runtime;
  19
  20 /** A JSContext that can be used in JS_SetPrivate and JS_GetPrivate
  21  * when no better one is available.  This context has no global
  22  * object, so scripts cannot be evaluated in it.
  23  *
  24  * XXX: This also works around a crash on exit.  SMJS will crash on
  25  * JS_DestroyRuntime if the given runtime has never had any context
  26  * created, which will be the case if one closes ELinks without having
  27  * loaded any documents.  */
  28 JSContext *spidermonkey_empty_context;
  29
  30 /** A reference count for ::spidermonkey_runtime so that modules using
  31  * it can be initialized and shut down in arbitrary order.  */
  32 static int spidermonkey_runtime_refcount;
  33
  34 /** Initialize ::spidermonkey_runtime and ::spidermonkey_empty_context.
  35  * If already initialized, just increment the reference count.
  36  *
  37  * @return 1 if successful or 0 on error.  If this succeeds, the
  38  * caller must eventually call spidermonkey_runtime_release().  */
  39 int
  40 spidermonkey_runtime_addref(void)
  41 {
  42         if (spidermonkey_runtime_refcount == 0) {
  43                 assert(spidermonkey_runtime == NULL);
  44                 assert(spidermonkey_empty_context == NULL);
  45                 if_assert_failed return 0;
  46
  47                 spidermonkey_runtime = JS_NewRuntime(4L * 1024L * 1024L);
  48                 if (!spidermonkey_runtime) return 0;
  49
  50                 spidermonkey_empty_context = JS_NewContext(spidermonkey_runtime,
  51                                                            0);
  52                 if (!spidermonkey_empty_context) {
  53                         /* Perhaps JS_DestroyRuntime will now crash
  54                          * because no context was created, but there's
  55                          * not much else to do.  */
  56                         JS_DestroyRuntime(spidermonkey_runtime);
  57                         spidermonkey_runtime = NULL;
  58                         JS_ShutDown();
  59                 }
  60         }
  61
  62         assert(spidermonkey_runtime);
  63         assert(spidermonkey_empty_context);
  64         spidermonkey_runtime_refcount++;
  65         assert(spidermonkey_runtime_refcount > 0);
  66         if_assert_failed { spidermonkey_runtime_refcount--; return 0; }
  67         return 1;
  68 }
  69
  70 /** Release a reference to ::spidermonkey_runtime, and destroy it if
  71  * that was the last reference.  If spidermonkey_runtime_addref()
  72  * failed, then this must not be called.  */
  73 void
  74 spidermonkey_runtime_release(void)
  75 {
  76         assert(spidermonkey_runtime_refcount > 0);
  77         assert(spidermonkey_runtime);
  78         assert(spidermonkey_empty_context);
  79         if_assert_failed return;
  80
  81         --spidermonkey_runtime_refcount;
  82         if (spidermonkey_runtime_refcount == 0) {
  83                 JS_DestroyContext(spidermonkey_empty_context);
  84                 spidermonkey_empty_context = NULL;
  85                 JS_DestroyRuntime(spidermonkey_runtime);
  86                 spidermonkey_runtime = NULL;
  87                 JS_ShutDown();
  88         }
  89 }
  90
  91 /** An ELinks-specific replacement for JS_DefineFunctions().
  92  *
  93  * @relates spidermonkeyFunctionSpec */
  94 JSBool
  95 spidermonkey_DefineFunctions(JSContext *cx, JSObject *obj,
  96                              const spidermonkeyFunctionSpec *fs)
  97 {
  98         for (; fs->name; fs++) {
  99                 if (!JS_DefineFunction(cx, obj, fs->name, fs->call,
 100                                        fs->nargs, 0))
 101                         return JS_FALSE;
 102         }
 103         return JS_TRUE;
 104 }
 105
 106 /** An ELinks-specific replacement for JS_InitClass().
 107  *
 108  * @relates spidermonkeyFunctionSpec */
 109 JSObject *
 110 spidermonkey_InitClass(JSContext *cx, JSObject *obj,
 111                        JSObject *parent_proto, JSClass *clasp,
 112                        JSNative constructor, uintN nargs,
 113                        JSPropertySpec *ps,
 114                        const spidermonkeyFunctionSpec *fs,
 115                        JSPropertySpec *static_ps,
 116                        const spidermonkeyFunctionSpec *static_fs)
 117 {
 118         JSObject *proto = JS_InitClass(cx, obj, parent_proto, clasp,
 119                                        constructor, nargs,
 120                                        ps, NULL, static_ps, NULL);
 121
 122         if (proto == NULL)
 123                 return NULL;
 124
 125         if (fs) {
 126                 if (!spidermonkey_DefineFunctions(cx, proto, fs))
 127                         return NULL;
 128         }
 129
 130         if (static_fs) {
 131                 JSObject *cons_obj = JS_GetConstructor(cx, proto);
 132
 133                 if (cons_obj == NULL)
 134                         return NULL;
 135                 if (!spidermonkey_DefineFunctions(cx, cons_obj, static_fs))
 136                         return NULL;
 137         }
 138
 139         return proto;
 140 }