<div dir="ltr"><div><div><div><div><div><div><div><div><div><div><div><div><div><div><div><div>I wonder if the same effect could be achieved by few smaller changes. What I'm thinking about is something like: </div>wl_resource_set_intact() </div>So far I've got three ways how to achieve that: </div>1) change scanner so that it saves opcode of destructor events in wl_interface, so when we invoke a closure, we can bail out if the resource is intact and it is not a destructor </div>2) do the same but with wl_message </div>These first two options would break ABI, so I'm not fond of these. </div>3) add a sign to the siganture that the message is a destructor. </div>I went ahead and tried the last one locally. Generally, it work like this: </div>get_closure() </div>if (resource_is_intact && message_is_not_destructor) </div> return </div><div>else</div> invoke </div>(message_is_not_destructor <=> signature does not contain 'D') </div>This approach does not break ABI and is nicely compatible with old protocols. It only adds one function wl_resource_set_intact() (thus changes API) and the protocols must be re-generated and re-linked, but since it is backward-compatible it is not crucial dependency (old protocols will work, but message_is_not_destructor always return true) </div>What do you think? </div>Cheers, </div>Marek <div><div><div><div><div><div><div> </div></div></div></div></div></div></div></div><div class="gmail_extra"> <div class="gmail_quote">On Wed, Feb 25, 2015 at 9:03 AM, David FORT <<a href="mailto:rdp.effort@gmail.com" target="_blank">rdp.effort@gmail.com</a>> wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">As stated in the very good blog post[1] of Pekka Paalanen, server-side we can have sometime troubles with object that the server has deleted but that the client is still requesting. This patch complements the scanner to create some code that will return inert objects, ie objects that will do nothing and will never return anything else but an inert object. An example is a get_pointer() on a wl_seat, with an unplugged mouse (and so no pointer). Instead of keeping alive the old pointer, we could bind that inert object and wait that the client release it (which should happen very quickly as a wl_global_remove should be in the wire). [1]: <a href="http://ppaalanen.blogspot.fi/2014/07/wayland-protocol-design-object-lifespan.html" target="_blank">http://ppaalanen.blogspot.fi/2014/07/wayland-protocol-design-object-lifespan.html</a> --- src/scanner.c | 173 +++++++++++++++++++++++++++++++++++++++++++++++++---- <a href="http://wayland-scanner.mk" target="_blank">wayland-scanner.mk</a> | 3 + 2 files changed, 166 insertions(+), 10 deletions(-) diff --git a/src/scanner.c b/src/scanner.c index 1f1e59a..dbdd1f6 100644 --- a/src/scanner.c +++ b/src/scanner.c @@ -39,7 +39,7 @@ enum side { static int usage(int ret) { - fprintf(stderr, "usage: ./scanner [client-header|server-header|code]\n"); + fprintf(stderr, "usage: ./scanner [client-header|server-header|code|server-inert]\n"); fprintf(stderr, "\n"); fprintf(stderr, "Converts XML protocol descriptions supplied on " "stdin to client headers,\n" @@ -626,6 +626,18 @@ emit_type(struct arg *a) } } +static struct arg * +get_return_type(struct message *m) +{ + struct arg *a, *ret = NULL; + + wl_list_for_each(a, &m->arg_list, link) { + if (a->type == NEW_ID) + ret = a; + } + return ret; +} + static void emit_stubs(struct wl_list *message_list, struct interface *interface) { @@ -688,11 +700,7 @@ emit_stubs(struct wl_list *message_list, struct interface *interface) continue; } - ret = NULL; - wl_list_for_each(a, &m->arg_list, link) { - if (a->type == NEW_ID) - ret = a; - } + ret = get_return_type(m); if (ret && ret->interface_name == NULL) printf("static inline void *\n"); @@ -1103,8 +1111,7 @@ emit_types(struct protocol *protocol, struct wl_list *message_list) case NEW_ID: case OBJECT: if (a->interface_name) - printf("\t&%s_interface,\n", - a->interface_name); + printf("\t&%s_interface,\n", a->interface_name); else printf("\tNULL,\n"); break; @@ -1248,6 +1255,140 @@ emit_code(struct protocol *protocol) } } +static void +emit_inert_request(struct protocol *protocol, struct interface *interface, struct wl_list *message_list) +{ + struct message *m; + struct arg *a, *ret; + const char *newid_name; + + wl_list_for_each(m, message_list, link) { + ret = get_return_type(m); + + /* forward declaration for the returned object */ + if (ret && ret->interface_name) { + printf("static void\n" + "create_inert_%s(struct wl_client *client, uint32_t version, uint32_t id);\n" + "\n", + ret->interface_name); + } + + printf("static inline void inert_%s_%s(struct wl_client *client, struct wl_resource *resource", + interface->name, m->name + ); + + wl_list_for_each(a, &m->arg_list, link) { + if (a->type == NEW_ID) { + newid_name = a->name; + + if (a->interface_name == NULL) { + printf(", const struct wl_interface *interface" + ", uint32_t version"); + continue; + } + } + + if (a->type == OBJECT) { + printf(", struct wl_resource *"); + } else { + printf(", "); + emit_type(a); + } + printf("%s", a->name); + } + + printf(")\n" + "{\n"); + + if (ret && ret->interface_name) { + printf("\tcreate_inert_%s(client, wl_resource_get_version(resource), %s);\n", + ret->interface_name, newid_name); + } else if (m->destructor) { + printf("\twl_resource_destroy(resource);\n"); + } + printf("}\n\n"); + } +} + +static void +emit_inert_interface(struct protocol *protocol, struct interface *i, struct wl_array *types) { + struct message *m; + + + if(wl_list_length(&i->request_list)) { + emit_inert_request(protocol, i, &i->request_list); + + printf ("static const struct %s_interface inert_%s_implementation = {\n", + i->name, i->name); + wl_list_for_each(m, &i->request_list, link) { + printf("\tinert_%s_%s,\n", i->name, m->name); + } + printf ("};\n" + "\n"); + } + + printf("static inline void\n" + "create_inert_%s(struct wl_client *client, uint32_t version, uint32_t id) {\n", + i->name + ); + + if(wl_list_length(&i->request_list)) { + /* emit the method body only when there is requests on the object */ + printf("\tstruct wl_resource *resource;\n" + "\tresource = wl_resource_create(client, &%s_interface, MIN(version, %d), id);\n" + "\twl_resource_set_implementation(resource, &inert_%s_implementation, NULL, wl_resource_destroy);\n", + i->name, i->version, i->name); + } + + printf("}\n" + "\n"); + +} + + +static +void emit_inert(struct protocol *protocol) { + struct interface *i; + struct wl_array types; + + if (protocol->copyright) + format_copyright(protocol->copyright); + + printf("#ifndef __%s_SERVER_INERT__\n" + "#define __%s_SERVER_INERT__\n" + "\n" + "#include \"%s-server-protocol.h\"\n" + "\n" + "#ifdef __cplusplus\n" + "extern \"C\" {\n" + "#endif\n" + "\n" + "#ifndef MIN\n" + "#define MIN(x,y) (((x) < (y)) ? (x) : (y))\n" + "#endif\n" + "\n", + protocol->uppercase_name, + protocol->uppercase_name, + //protocol->name, + protocol->name + ); + + wl_list_for_each(i, &protocol->interface_list, link) { + if (!strcmp(i->name, "wl_registry") || !strcmp(i->name, "wl_display")) + continue; + + emit_inert_interface(protocol, i, &types); + } + + printf("\n" + "#ifdef __cplusplus\n" + "}\n" + "#endif\n" + "\n" + "#endif\n"); + +} + int main(int argc, char *argv[]) { struct parse_context ctx; @@ -1257,17 +1398,26 @@ int main(int argc, char *argv[]) enum { CLIENT_HEADER, SERVER_HEADER, + SERVER_INERT, CODE, } mode; - if (argc != 2) + if (argc < 2) { usage(EXIT_FAILURE); - else if (strcmp(argv[1], "help") == 0 || strcmp(argv[1], "--help") == 0) + } + + if (argc > 2) { + stdin = fopen(argv[2], "r"); + } + + if (strcmp(argv[1], "help") == 0 || strcmp(argv[1], "--help") == 0) usage(EXIT_SUCCESS); else if (strcmp(argv[1], "client-header") == 0) mode = CLIENT_HEADER; else if (strcmp(argv[1], "server-header") == 0) mode = SERVER_HEADER; + else if (strcmp(argv[1], "server-inert") == 0) + mode = SERVER_INERT; else if (strcmp(argv[1], "code") == 0) mode = CODE; else @@ -1317,6 +1467,9 @@ int main(int argc, char *argv[]) case SERVER_HEADER: emit_header(&protocol, SERVER); break; + case SERVER_INERT: + emit_inert(&protocol); + break; case CODE: emit_code(&protocol); break; diff --git a/<a href="http://wayland-scanner.mk" target="_blank">wayland-scanner.mk</a> b/<a href="http://wayland-scanner.mk" target="_blank">wayland-scanner.mk</a> index 0a72062..fd994e0 100644 --- a/<a href="http://wayland-scanner.mk" target="_blank">wayland-scanner.mk</a> +++ b/<a href="http://wayland-scanner.mk" target="_blank">wayland-scanner.mk</a> @@ -6,3 +6,6 @@ %-client-protocol.h : $(wayland_protocoldir)/%.xml $(AM_V_GEN)$(wayland_scanner) client-header < $< > $@ + +%-server-inert.h: $(wayland_protocoldir)/%.xml + $(AM_V_GEN)$(wayland_scanner) server-inert < $< > $@ \ No newline at end of file -- 1.9.1 _______________________________________________ wayland-devel mailing list <a href="mailto:wayland-devel@lists.freedesktop.org">wayland-devel@lists.freedesktop.org</a> <a href="http://lists.freedesktop.org/mailman/listinfo/wayland-devel" target="_blank">http://lists.freedesktop.org/mailman/listinfo/wayland-devel</a> </blockquote></div> </div>