[PATCH V2] wayland.xml: add "enum", "bitfield" and "is_bitfield" attributes
Nils Chr. Brause
nilschrbrause at gmail.com
Mon Sep 22 09:30:16 PDT 2014
On Mon, Sep 22, 2014 at 11:21 AM, Pekka Paalanen <ppaalanen at gmail.com> wrote:
>
> On Wed, 3 Sep 2014 19:44:04 +0200
> "Nils Chr. Brause" <nilschrbrause at gmail.com> wrote:
>
> > This replaces "[PATCH wayland] Add "enum" attribute to "arg" elements".
> > Previous concers have be incorporated and it is meant for 1.7.
> >
> > From 733fb18b163de93276f092a4be100c7e0c0c723f Mon Sep 17 00:00:00 2001
> > From: "Nils Chr. Brause" <nilschrbrause at googlemail.com>
> > Date: Wed, 3 Sep 2014 19:18:28 +0200
> > Subject: [PATCH] wayland.xml: add "enum", "bitfield" and "is_bitfield"
> > attributes
> >
> > There are programming languages, that are more strongly typed than
> > C. People creating Wayland bindings for these languages will want to
> > make use of this strong type system by declaring each enumeration a
> > distinct type and differentiating between enumerations and bit fields.
> >
> > For code generation to work with these languages, there needs to be
> > information about which enumerations are actually bit fields and which
> > enumerations or bit fields may be passed/received in which
> > request/event arguments.
> >
> > This is accomplished by adding an "is_bitfield" attribute to "enum"
> > elements, which are actually bitfields and by adding "enum" or
> > "bitfield" attributes to the "arg" elements of requests and
> > events. The values of the "enum" and "bitfield" attributes have the
> > format "$interface.$name", where "$interface" is the name of the
> > interface, where the enumeration or bit field is declared and "$name"
> > is the name of the enumeration or bit field, which is used in this
> > argument.
> >
> > The scanner has been modified to enforce those rules.
> > ---
> > protocol/wayland.dtd | 3 ++
> > protocol/wayland.xml | 42 ++++++++++-----------
> > src/scanner.c | 101 ++++++++++++++++++++++++++++++++++++++++++++++++++-
> > 3 files changed, 124 insertions(+), 22 deletions(-)
> >
> > diff --git a/protocol/wayland.dtd b/protocol/wayland.dtd
> > index b8b1573..4506201 100644
> > --- a/protocol/wayland.dtd
> > +++ b/protocol/wayland.dtd
> > @@ -14,6 +14,7 @@
> > <!ELEMENT enum (description?,entry*)>
> > <!ATTLIST enum name CDATA #REQUIRED>
> > <!ATTLIST enum since CDATA #IMPLIED>
> > + <!ATTLIST enum is_bitfield CDATA #IMPLIED>
> > <!ELEMENT entry (description?)>
> > <!ATTLIST entry name CDATA #REQUIRED>
> > <!ATTLIST entry value CDATA #REQUIRED>
> > @@ -25,5 +26,7 @@
> > <!ATTLIST arg summary CDATA #IMPLIED>
> > <!ATTLIST arg interface CDATA #IMPLIED>
> > <!ATTLIST arg allow-null CDATA #IMPLIED>
> > + <!ATTLIST arg enum CDATA #IMPLIED>
> > + <!ATTLIST arg bitfield CDATA #IMPLIED>
> > <!ELEMENT description (#PCDATA)>
> > <!ATTLIST description summary CDATA #REQUIRED>
> > diff --git a/protocol/wayland.xml b/protocol/wayland.xml
> > index bb457bc..878c347 100644
> > --- a/protocol/wayland.xml
> > +++ b/protocol/wayland.xml
> > @@ -229,7 +229,7 @@
> > <arg name="width" type="int"/>
> > <arg name="height" type="int"/>
> > <arg name="stride" type="int"/>
> > - <arg name="format" type="uint"/>
> > + <arg name="format" type="uint" enum="wl_shm.format"/>
> > </request>
> >
> > <request name="destroy" type="destructor">
> > @@ -367,7 +367,7 @@
> > can be used for buffers. Known formats include
> > argb8888 and xrgb8888.
> > </description>
> > - <arg name="format" type="uint"/>
> > + <arg name="format" type="uint" enum="wl_shm.format"/>
> > </event>
> > </interface>
> >
> > @@ -723,7 +723,7 @@
> > <arg name="serial" type="uint" summary="serial of the implicit grab on the pointer"/>
> > </request>
> >
> > - <enum name="resize">
> > + <enum name="resize" is_bitfield="true">
> > <description summary="edge values for resizing">
> > These values are used to indicate which edge of a surface
> > is being dragged in a resize operation. The server may
> > @@ -751,7 +751,7 @@
> > </description>
> > <arg name="seat" type="object" interface="wl_seat" summary="the wl_seat whose pointer is used"/>
> > <arg name="serial" type="uint" summary="serial of the implicit grab on the pointer"/>
> > - <arg name="edges" type="uint" summary="which edge or corner is being dragged"/>
> > + <arg name="edges" type="uint" summary="which edge or corner is being dragged" bitfield="wl_shell_surface.resize"/>
> > </request>
> >
> > <request name="set_toplevel">
> > @@ -762,7 +762,7 @@
> > </description>
> > </request>
> >
> > - <enum name="transient">
> > + <enum name="transient" is_bitfield="true">
> > <description summary="details of transient behaviour">
> > These flags specify details of the expected behaviour
> > of transient surfaces. Used in the set_transient request.
> > @@ -784,7 +784,7 @@
> > <arg name="parent" type="object" interface="wl_surface"/>
> > <arg name="x" type="int"/>
> > <arg name="y" type="int"/>
> > - <arg name="flags" type="uint"/>
> > + <arg name="flags" type="uint" bitfield="wl_shell_surface.transient"/>
> > </request>
> >
> > <enum name="fullscreen_method">
> > @@ -835,7 +835,7 @@
> > with the dimensions for the output on which the surface will
> > be made fullscreen.
> > </description>
> > - <arg name="method" type="uint"/>
> > + <arg name="method" type="uint" enum="wl_shell_surface.fullscreen_method"/>
> > <arg name="framerate" type="uint"/>
> > <arg name="output" type="object" interface="wl_output" allow-null="true"/>
> > </request>
> > @@ -868,7 +868,7 @@
> > <arg name="parent" type="object" interface="wl_surface"/>
> > <arg name="x" type="int"/>
> > <arg name="y" type="int"/>
> > - <arg name="flags" type="uint"/>
> > + <arg name="flags" type="uint" bitfield="wl_shell_surface.transient"/>
> > </request>
> >
> > <request name="set_maximized">
> > @@ -949,7 +949,7 @@
> > in surface local coordinates.
> > </description>
> >
> > - <arg name="edges" type="uint"/>
> > + <arg name="edges" type="uint" bitfield="wl_shell_surface.resize"/>
> > <arg name="width" type="int"/>
> > <arg name="height" type="int"/>
> > </event>
> > @@ -1242,7 +1242,7 @@
> > wl_output.transform enum the invalid_transform protocol error
> > is raised.
> > </description>
> > - <arg name="transform" type="int"/>
> > + <arg name="transform" type="int" bitfield="wl_output.transform"/>
> > </request>
> >
> > <!-- Version 3 additions -->
> > @@ -1285,7 +1285,7 @@
> > maintains a keyboard focus and a pointer focus.
> > </description>
> >
> > - <enum name="capability">
> > + <enum name="capability" is_bitfield="true">
> > <description summary="seat capability bitmask">
> > This is a bitmask of capabilities this seat has; if a member is
> > set, then it is present on the seat.
> > @@ -1301,7 +1301,7 @@
> > keyboard or touch capabilities. The argument is a capability
> > enum containing the complete set of capabilities this seat has.
> > </description>
> > - <arg name="capabilities" type="uint"/>
> > + <arg name="capabilities" type="uint" bitfield="wl_seat.capability"/>
> > </event>
> >
> > <request name="get_pointer">
> > @@ -1461,7 +1461,7 @@
> > <arg name="serial" type="uint"/>
> > <arg name="time" type="uint" summary="timestamp with millisecond granularity"/>
> > <arg name="button" type="uint"/>
> > - <arg name="state" type="uint"/>
> > + <arg name="state" type="uint" enum="wl_pointer.button_state"/>
> > </event>
> >
> > <enum name="axis">
> > @@ -1493,7 +1493,7 @@
> > </description>
> >
> > <arg name="time" type="uint" summary="timestamp with millisecond granularity"/>
> > - <arg name="axis" type="uint"/>
> > + <arg name="axis" type="uint" enum="wl_pointer.axis"/>
> > <arg name="value" type="fixed"/>
> > </event>
> >
> > @@ -1527,7 +1527,7 @@
> > This event provides a file descriptor to the client which can be
> > memory-mapped to provide a keyboard mapping description.
> > </description>
> > - <arg name="format" type="uint"/>
> > + <arg name="format" type="uint" enum="wl_keyboard.keymap_format"/>
> > <arg name="fd" type="fd"/>
> > <arg name="size" type="uint"/>
> > </event>
> > @@ -1572,7 +1572,7 @@
> > <arg name="serial" type="uint"/>
> > <arg name="time" type="uint" summary="timestamp with millisecond granularity"/>
> > <arg name="key" type="uint"/>
> > - <arg name="state" type="uint"/>
> > + <arg name="state" type="uint" enum="wl_keyboard.key_state"/>
> > </event>
> >
> > <event name="modifiers">
> > @@ -1714,7 +1714,7 @@
> > <entry name="vertical_bgr" value="5"/>
> > </enum>
> >
> > - <enum name="transform">
> > + <enum name="transform" is_bitfield="true">
> > <description summary="transform from framebuffer to output">
> > This describes the transform that a compositor will apply to a
> > surface to compensate for the rotation or mirroring of an
> > @@ -1753,17 +1753,17 @@
> > summary="width in millimeters of the output"/>
> > <arg name="physical_height" type="int"
> > summary="height in millimeters of the output"/>
> > - <arg name="subpixel" type="int"
> > + <arg name="subpixel" type="int" enum="wl_output.subpixel"
> > summary="subpixel orientation of the output"/>
> > <arg name="make" type="string"
> > summary="textual description of the manufacturer"/>
> > <arg name="model" type="string"
> > summary="textual description of the model"/>
> > - <arg name="transform" type="int"
> > + <arg name="transform" type="int" bitfield="wl_output.transform"
> > summary="transform that maps framebuffer to output"/>
> > </event>
> >
> > - <enum name="mode">
> > + <enum name="mode" is_bitfield="true">
> > <description summary="mode information">
> > These flags describe properties of an output mode.
> > They are used in the flags bitfield of the mode event.
> > @@ -1790,7 +1790,7 @@
> > the output may be scaled, as described in wl_output.scale,
> > or transformed , as described in wl_output.transform.
> > </description>
> > - <arg name="flags" type="uint" summary="bitfield of mode flags"/>
> > + <arg name="flags" type="uint" summary="bitfield of mode flags" bitfield="wl_output.mode"/>
> > <arg name="width" type="int" summary="width of the mode in hardware units"/>
> > <arg name="height" type="int" summary="height of the mode in hardware units"/>
> > <arg name="refresh" type="int" summary="vertical refresh rate in mHz"/>
> > diff --git a/src/scanner.c b/src/scanner.c
> > index 72fd3e8..b240790 100644
> > --- a/src/scanner.c
> > +++ b/src/scanner.c
> > @@ -112,6 +112,8 @@ struct arg {
> > enum arg_type type;
> > int nullable;
> > char *interface_name;
> > + char *enum_name;
> > + char *bitfield_name;
> > struct wl_list link;
> > char *summary;
> > };
> > @@ -119,6 +121,7 @@ struct arg {
> > struct enumeration {
> > char *name;
> > char *uppercase_name;
> > + int is_bitfield;
> > struct wl_list entry_list;
> > struct wl_list link;
> > struct description *description;
> > @@ -314,7 +317,7 @@ start_element(void *data, const char *element_name, const char **atts)
> > struct entry *entry;
> > struct description *description;
> > const char *name, *type, *interface_name, *value, *summary, *since;
> > - const char *allow_null;
> > + const char *allow_null, *enum_name, *bitfield_name, *is_bitfield;
> > char *end;
> > int i, version;
> >
> > @@ -323,11 +326,14 @@ start_element(void *data, const char *element_name, const char **atts)
> > type = NULL;
> > version = 0;
> > interface_name = NULL;
> > + enum_name = NULL;
> > + bitfield_name = NULL;
> > value = NULL;
> > summary = NULL;
> > description = NULL;
> > since = NULL;
> > allow_null = NULL;
> > + is_bitfield = NULL;
> > for (i = 0; atts[i]; i += 2) {
> > if (strcmp(atts[i], "name") == 0)
> > name = atts[i + 1];
> > @@ -339,12 +345,18 @@ start_element(void *data, const char *element_name, const char **atts)
> > value = atts[i + 1];
> > if (strcmp(atts[i], "interface") == 0)
> > interface_name = atts[i + 1];
> > + if (strcmp(atts[i], "enum") == 0)
> > + enum_name = atts[i + 1];
> > + if (strcmp(atts[i], "bitfield") == 0)
> > + bitfield_name = atts[i + 1];
> > if (strcmp(atts[i], "summary") == 0)
> > summary = atts[i + 1];
> > if (strcmp(atts[i], "since") == 0)
> > since = atts[i + 1];
> > if (strcmp(atts[i], "allow-null") == 0)
> > allow_null = atts[i + 1];
> > + if (strcmp(atts[i], "is_bitfield") == 0)
> > + is_bitfield = atts[i + 1];
> > }
> >
> > ctx->character_data_length = 0;
> > @@ -461,9 +473,31 @@ start_element(void *data, const char *element_name, const char **atts)
> > else
> > arg->interface_name = NULL;
> > break;
> > + case UNSIGNED:
> > + case INT:
> > + if (enum_name) {
> > + arg->enum_name = xstrdup(enum_name);
> > + arg->bitfield_name = NULL;
> > + }
> > + else if (bitfield_name) {
> > + arg->bitfield_name = xstrdup(bitfield_name);
> > + arg->enum_name = NULL;
> > + }
> > + else {
> > + arg->bitfield_name = NULL;
> > + arg->enum_name = NULL;
> > + }
> > +
> > + if (enum_name && bitfield_name)
> > + fail(&ctx->loc, "bitfield and enum attribute cannot both be set");
> > + break;
> > default:
> > if (interface_name != NULL)
> > fail(&ctx->loc, "interface attribute not allowed for type %s", type);
> > + if (enum_name != NULL)
> > + fail(&ctx->loc, "enum attribute not allowed for type %s", type);
> > + if (bitfield_name != NULL)
> > + fail(&ctx->loc, "bitfield attribute not allowed for type %s", type);
>
> This looks broken.
>
> What if
> - int or unsigned has "interface" attribute? It should be an error.
> - new_id or object has "enum" or "bitfield" attribute? Should be an
> error.
>
> You probably want your own switch-clause.
Wouldn't a separate switch-clause require a new type? I thought,
this is not what we want, since this would break other parsers.
I would probably just check for additional unwanted combinations.
>
> > break;
> > }
> >
> > @@ -497,6 +531,13 @@ start_element(void *data, const char *element_name, const char **atts)
> > &enumeration->link);
> >
> > ctx->enumeration = enumeration;
> > +
> > + if (is_bitfield == NULL || strcmp(is_bitfield, "false") == 0)
> > + enumeration->is_bitfield = 0;
> > + else if (strcmp(is_bitfield, "true") == 0)
> > + enumeration->is_bitfield = 1;
> > + else
> > + fail(&ctx->loc, "invalid value for is_bitfield attribute (%s)", is_bitfield);
> > } else if (strcmp(element_name, "entry") == 0) {
> > if (name == NULL)
> > fail(&ctx->loc, "no entry name given");
> > @@ -1246,6 +1287,60 @@ emit_code(struct protocol *protocol)
> > }
> > }
> >
> > +static int
> > +enum_exists(struct protocol *protocol, const char *enum_name, int is_bitfield)
> > +{
> > + struct interface *i;
> > + struct enumeration *e;
> > + char full_name[64];
> > +
> > + wl_list_for_each(i, &protocol->interface_list, link) {
> > + wl_list_for_each(e, &i->enumeration_list, link) {
> > + sprintf(full_name, "%s.%s", i->name, e->name);
>
> Use snprintf to avoid buffer overflows.
> Or split enum_name, and match both halves separately.
I will split enum_name then.
>
> > + if (strcmp(full_name, enum_name) == 0 &&
> > + e->is_bitfield == is_bitfield)
> > + return 1;
> > + }
> > + }
> > + return 0;
> > +}
> > +
> > +static void
> > +check_message(struct protocol *protocol, struct message *m)
> > +{
> > + struct arg *a;
> > +
> > + wl_list_for_each(a, &m->arg_list, link)
> > + if ((a->type == UNSIGNED || a->type == INT)) {
> > + if (a->enum_name != NULL &&
> > + !enum_exists(protocol, a->enum_name, 0)) {
> > + fprintf(stderr, "enum %s does not exist\n",
> > + a->enum_name);
> > + exit(EXIT_FAILURE);
> > + }
> > + else if (a->bitfield_name != NULL &&
> > + !enum_exists(protocol, a->bitfield_name, 1)) {
> > + fprintf(stderr, "bitfield %s does not exist\n",
> > + a->enum_name);
> > + exit(EXIT_FAILURE);
> > + }
> > + }
> > +}
> > +
> > +static void
> > +check_protocol(struct protocol *protocol)
> > +{
> > + struct interface *i;
> > + struct message *m;
> > +
> > + wl_list_for_each(i, &protocol->interface_list, link) {
> > + wl_list_for_each(m, &i->request_list, link)
> > + check_message(protocol, m);
> > + wl_list_for_each(m, &i->event_list, link)
> > + check_message(protocol, m);
> > + }
> > +}
> > +
> > int main(int argc, char *argv[])
> > {
> > struct parse_context ctx;
> > @@ -1302,6 +1397,10 @@ int main(int argc, char *argv[])
> >
> > XML_ParserFree(ctx.parser);
> >
> > + /* some checks can only be performed after *
> > + * the whole protocol has been read in */
> > + check_protocol(&protocol);
> > +
> > switch (mode) {
> > case CLIENT_HEADER:
> > emit_header(&protocol, CLIENT);
>
> Should we also enforce, that only UNSIGNED is valid for bitfields?
I would certainly like to do this, but wl_output.transform is
always passed as a signed integer and I'm not sure if this is a
bitfield or not. I assumed it is, because you can
reconstruct "270", "flipped_90", "flipped_180" and "flipped_270"
out of "90", "180" and "flipped". Or is this just a coincidence?
Also, is there a reason why some enumerations are passed as
a signed integer (wl_output.subpixel) and others aren't?
>
> So, what do other people think of the idea in this patch?
>
> I want to see some other Wayland developers support this, as I am not
> confident with my own judgement here.
>
>
> Thanks,
> pq
Cheers,
Nils
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