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diff --git a/resproto.txt b/resproto.txt new file mode 100644 index 0000000..8b322ff --- /dev/null +++ b/resproto.txt @@ -0,0 +1,462 @@ + DRAFT FOR REVIEW + The X Resource Extension + Version 1.2 + Rami Ylimäki + rami.ylimaki@vincit.fi + + ❧❧❧❧❧❧❧❧❧❧❧ + +1. Introduction + +The protocol description of X Resource Extension version 1.1 has been +either lost or has never been written. This specification documents +version 1.0 based on reverse engineered library and server +code. Version 1.1 has been accidentally released from the version +control and while it doesn't have differences to version 1.0, this +version is labeled 1.2 in order to remove the risk of confusion. In +addition to the 1.0 description, this document introduces a new 1.2 +version of the extension. + +Version 1.2 is a minor release and therefore the changes are +compatible with the previous version. Main enhancements over version +1.0 are: + +- Client identification is now possible. For example, servers + supporting version 1.2 may report PID of local clients. + +- Size of any resource can be queried from the server. Servers may not + necessarily support size calculation for every resource. However, + clients have now at least the chance to let the server do resource + size estimation for them. + + ❧❧❧❧❧❧❧❧❧❧❧ + +2. Notations used in this document + +Notation for data types and requests follows the guidelines set in +sections 2-4 of X Window System Protocol standard. + + ❧❧❧❧❧❧❧❧❧❧❧ + +3. Interoperability between version 1.1 and 1.2 + +Version 1.2 only introduces two new requests. However, these requests +could be seen as generalized versions of existing requests. Even +though we aren't deprecating any old requests, libraries could +implement some old requests using the new ones. + +The new XResQueryClientIds request could be used instead of +XResQueryClients. + +The new XResQueryResourceBytes request could be used instead of +XResQueryClientPixmapBytes. + +Using the old requests is still acceptable because we don't want to +change the semantics of existing requests between version 1.1 and 1.2. + + ❧❧❧❧❧❧❧❧❧❧❧ + +4. Data types + +4.1 Types in version 1.0 + +CLIENTXIDRANGE [ resource_base: CARD32 + resource_mask: CARD32 ] + +This type is used for reply of XResQueryClients in version 1.1. It +represents the range of resource allocated for a client and can be +also used for client identification. + +resource_base + First resource ID reserved for a client. Used also to identify the + clients themselves. +resource_mask + Mask that can be used to identify a client from some resource + ID. Just zero the bits indicated by this mask from any resource ID + to identify the client that owns the resource. + +CLIENTXID [ client: XID ] + +This type identifies a single client by a resource owned by that +client or by the first resource ID allocated for the client +(resource_base of CLIENTXIDRANGE). Whenever a resource ID is used, it +is masked by resource_mask of CLIENTXIDRANGE to find out the client +that owns the resource. + +CLIENTRESOURCETYPECOUNT [ resource_type: ATOM + count: CARD32 ] + +This type is used for reply of XResQueryClientResources in version +1.1. It represents the number of certain type of resources that are +owned by some client. + +resource_type + Atom specifying the type of a resource. +count + Number of resources of the given type owned by a client. + +4.2 Types in version 1.2 + +4.2.1 Types used by XResQueryClientIds + +CLIENTIDMASK { ClientXid = 0x1, LocalClientPid = 0x2 } + +A bitmask specifying a client identification method. Currently only +the PID of local clients is supported in the form of +LocalClientPid. ClientXid is provided for backward compatibility with +version 1.0 so that the new 1.2 requests (XResQueryClientIds) can be +used in place of the older ones (XResQueryClients). + +CLIENTIDSPEC [ client: CLIENTXID or None + mask: SETofCLIENTIDMASK or None ] + +A data structure for selecting client IDs. + +client + ID of a resource allocated for some client. Only the part + identifying a client is actually used. The resource_base of + CLIENTXIDRANGE can be used if the client doesn't own any + resources. However, any resource ID is accepted because that makes + identifying the owners of existing resources easy. The null + resource None can be used to select all clients. +mask + Collection of identification methods that should be applied on the + client. The special value None can be used to apply all supported + identification methods. + +CLIENTIDVALUE [ spec: CLIENTIDSPEC + length: CARD32 + value: LISTofCARD32 ] + +A data structure specifying a single client ID. + +spec + A unique identifier for a specific ID of some client. Wildcards + such as None and bitmask unions aren't allowed. The data structure + must always identify a single client and single ID type. However, + the client doesn't have to be specified as the resource_base of + CLIENTXIDRANGE and can be any resource owned by the client. +length + Specifies the length of an ID in units of CARD32. The length + depends on the ID type. In version 1.2 the lengths are 0 for + ClientXid and 4 for LocalClientPid. The length of ClientXid is 0 + because that is already stored in the spec field. +value + Actual ID data. In version 1.2 this is missing for ClientXid and + consists of a single CARD32 for LocalClientPid. + +4.2.2 Types used by XResQueryResourceBytes + +To better understand how resources are related to each other, it's +useful to introduce the concepts of main resource and cross +reference. By main resource we just mean a normal resource that has a +valid XID. By cross reference we mean a resource that is used by some +other resource. + +The same resource may have both of these roles depending on the +context. For example, there could be an ordinary pixmap resource. When +we talk about this resource in isolation the term main resource is +used. We call the exact same resource a cross reference when we are +concentrating on some higher level resource, such as window or +graphics context, that is using the lower level resource. Cross +references may also be internal server resources that don't have a +valid XID. + +RESOURCEIDSPEC [ resource: XID or None + type: ATOM or None/AnyPropertyType ] + +A data structure for selecting or identifying resources. The +interpretation of fields changes depending on the context. The +differences in interpretation are described below. + +resource + An XID of a resource. The null resource None can be used to select + all resources matching some type if the data structure is used in + XResQueryResourceBytes request. The null resource None can be used + to mark private server resources if the data structure is used in + a cross reference of XResQueryResourceBytes reply. +type + An atom identifying the resource type. The null atom + None/AnyPropertyType can be used to select all resource types + matching some resource ID if the data structure is used in + XResQueryResourceBytes request. + +RESOURCESIZESPEC [ spec: RESOURCEIDSPEC + bytes: CARD32 + ref_count: CARD32 + use_count: CARD32 ] + +A data structure specifying the size of a single resource. + +spec + Uniquely identifies a single resource. Wildcards such as None and + AnyPropertyType aren't allowed for main resources. In cross + references, None is used to mark internal server resources. +bytes + Number of bytes allocated for the resource. The size of a resource + is never divided by a reference count. This is the number of bytes + released in server when there are no more references left to the + resource. +ref_count + Number of total users of the resource. Typically the reference + count is 1 but for pixmaps and other resources used from different + contexts the count may be larger. +use_count + Number of times the resource is used by some other resource. For + main resources this is typically 1, because a resource doesn't + usually use itself recursively. For cross references this is the + number of times the resource is used and is also 1 usually. + +RESOURCESIZEVALUE [ size: RESOURCESIZESPEC + num_cross_references: CARD32 + cross_references: LISTofRESOURCESIZESPEC ] + +A data structure specifying sizes of cross references to other +resources in addition to the main resource size. + +size + Size of a main resource. +num_cross_references + Number of cross references to other resources from the main + resource. Currently resources can only have pixmaps as cross + references but this can be extended to other types in the + future. For simple resources this field is therefore 0 and the + cross_references list is missing. +cross_references: + Size specifications for cross references. Note that cross + references may contain resources that don't have a valid XID. For + example, a DRI2 drawable might have a cross reference to a private + pixmap that is used internally in the server only. These private + cross references are contained in this list also. This makes it + possible to emulate XResGetClientPixmapBytes with + XResGetResourceBytes. + + ❧❧❧❧❧❧❧❧❧❧❧ + +5. Requests + +5.1 Requests in version 1.0 + +┌─── + XResQueryVersion + client_major: CARD8 + client_minor: CARD8 + ▶ + server_major: CARD16 + server_minor: CARD16 +└─── + +The client sends the highest supported version to the server and the +server sends the highest version it supports, but no higher than the +requested version. Major version changes can introduce +incompatibilities in existing functionality, minor version changes +introduce only backward compatible changes. It is the client's +responsibility to ensure that the server supports a version which is +compatible with its expectations. + +client_major + Major X Resource Extension version supported by client. +client_minor + Minor X Resource Extension version supported by client. +server_major + Highest version supported by server that is compatible with + client. +server_minor + Highest version supported by server that is compatible with + client. + +┌─── + XResQueryClients + ▶ + num_clients: CARD32 + clients: LISTofCLIENTXIDRANGE +└─── + +The request asks X server to return the list of all currently +connected clients. + +num_clients + Number of currently connected clients. +clients + List of XID ranges allocated for the connected clients. + +┌─── + XResQueryClientResources + client: CLIENTXID + ▶ + num_types: CARD32 + types: LISTofCLIENTRESOURCETYPECOUNT + + Errors: Value +└─── + +This request can be used to ask the number of resources owned by a +client. The server will return the counts of each type of resource. + +client + An XID in the resource range of a client. This identifies the + client and not some specific resource. +num_types + Number of different resource types owned by the client. +types + A list of counts for each resource type. + +A value error is generated if invalid resource or client XID is given +in the request. + +┌─── + XResQueryClientPixmapBytes + client: CLIENTXID + ▶ + bytes: CARD32 + bytes_overflow: CARD32 + + Errors: Value +└─── + +This request is used to get the pixmap usage of some client. The +returned number is a sum of memory usage of each pixmap that can be +attributed to the given client. Ideally the server goes through all +pixmaps and divides each pixmap size by the pixmap reference count to +get a pixmap reference size. The reference size is then added to the +returned sum if the client happens to be referencing that pixmap. In +practice some pixmap references may be missed, because it would be too +difficult to keep track of all pixmap references. However, the server +will check the most important client resources that are using pixmaps +and tries to estimate the pixmap usage as well as is possible. In +other words, the server need only make a best-effort attempt to +calculate resource source, so actual resource size may differ from +that reported in practice. + +client + Identifies a client by an ID in its resource ID range. +bytes: + Number of bytes attributed to pixmap references from the client + resources. +bytes_overflow: + Higher order word for the bytes field in case the sum of pixmap + reference sizes doesn't fit in CARD32. + +A value error is generated if invalid resource or client XID is given +in the request. + +5.2 Requests in version 1.2 + +┌─── + XResQueryClientIds + num_specs: CARD32 + client_specs: LISTofCLIENTIDSPEC + ▶ + num_ids: CARD32 + client_ids: LISTofCLIENTIDVALUE + + Errors: Value +└─── + +XResQueryClientIds can be used to identify a given set of clients with +some identification method. The request sends a list of specifiers +that select clients and identification methods to server. The server +then tries to identify the chosen clients using the identification +methods specified for each client. The server returns IDs for those +clients that were successfully identified. It's not an error condition +if some identification method couldn't be applied to a client. If the +server is unable to identify some clients, they simply aren't included +in the returned list. + +The request supports wildcards in the client specifications so that in +the most general case all IDs of all clients can be queried with a +single CLIENTIDSPEC. + +The CLIENTIDSPEC of request and CLIENTIDSPEC of CLIENTIDVALUE in reply +usually match each other. For example, if a request selected a client +by a resource ID owned by the client, then the client is identified by +the same resource ID in the reply. This has been done so that it would +be easy to identify an owner of some resource. + +However, the CLIENTIDSPEC of returned CLIENTIDVALUE never contains any +wildcards. If the request used a wildcard to specify all clients in a +single CLIENTIDSPEC, then the reply has expanded the wildcard and +returns separate CLIENTIDVALUE records for each client. In this case +wildcarded clients are identified by resource_base of CLIENTXIDRANGE. + +The LocalClientPid type of IDs are included in the reply list only if +the client executing the request asked for it and was also a local +client itself. It doesn't make sense for remote clients to ask PIDs of +local clients. + +num_specs + Number of client ID specifications. +client_specs + A list specifying identification methods for clients. Supports + multiple identification methods and clients in a single + specification. See CLIENTIDSPEC for details. +num_ids + Number of IDs that were successfully determined. Can be different + from num_specs or even zero if the server didn't support any + identification methods for the given clients. +client_ids + A list specifying ID information for successfully identified + clients. If wildcards were used in a single CLIENTIDSPEC of + client_specs, then multiple CLIENTIDVALUE records may be returned + for that CLIENTIDSPEC. See CLIENTIDVALUE for details. + +A Value error is returned if the request specifies an invalid client +XID or invalid identification method type. + +┌─── + XResQueryResourceBytes + client: CLIENTXID or None + num_specs: CARD32 + resource_specs: LISTofRESOURCEIDSPEC + ▶ + num_sizes: CARD32 + sizes: LISTofRESOURCESIZEVALUE + + Errors: Atom, Value +└─── + +XResQueryResourceBytes can be used to ask the sizes of resources from +X server. The request sends a list of specifiers that selects +resources for size calculation. The server tries to calculate the +sizes of chosen resources and returns an estimate for a resource only +if the size could be determined. It's not an error condition if a size +couldn't be calculated. In that case the resources simply aren't +included in the returned list. + +The request supports wildcards so that in the most general case sizes +of all resources of all clients can be queried with a single +RESOURCEIDSPEC. However, the reply has all wildcards expanded and +reports a size of a single resource in each RESOURCESIZEVALUE. + +client + An ID of a client can be given to limit the query to resources of + that client. Just like in CLIENTIDSPEC, any resource ID can be + given to identify a client and None can be used if the query + shouldn't be limited to a specific client. Note that in some cases + this field is redundant because resource_specs already fully + determines which resources are selected. If the client ID doesn't + match the owner of any resource in resource_specs, no sizes are + returned and no error is generated. +num_specs + Number of resource specifications. +resource_specs + A list of resource specifications. Each specification can either + uniquely identify a single resource or multiple resources if + wildcarding is used. See RESOURCEIDSPEC for details. +num_sizes + Number of resources whose size could be determined. Can be + different from num_specs or even zero if the server didn't support + size calculation for the given resources. +sizes + A list of resource sizes. Each resource size is linked to a unique + resource. Wildcards are never used in the returned size + records. For example, it's not possible to receive a single + RESOURCESIZEVALUE that would specify the size of all pixmaps if + the sizes of pixmap type resources were asked. Instead, a single + RESOURCESIZEVALUE would be returned for each pixmap in that case. + +An Atom error is returned if the request specifies an invalid resource +type. A Value error is returned if the request specifies an invalid +XID for a client or a resource. + + ❧❧❧❧❧❧❧❧❧❧❧ |