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2016-03-05qapi: Update docs to match recent generator changesEric Blake
Several commits have been changing the generator, but not updating the docs to match: - The implicit tag member is named "type", not "kind". Screwed up in commit 39a1815. - Commit 9f08c8ec made list types lazy, and thereby dropped UserDefOneList if nothing explicitly uses the list type. - Commit 51e72bc1 switched the parameter order with 'name' occurring earlier. - Commit e65d89bf changed the layout of UserDefOneList. - Prefer the term 'member' over 'field'. - We now expose visit_type_FOO_members() for objects. - etc. Rework the examples to show slightly more output (we don't want to show too much; that's what the testsuite is for), and regenerate the output to match all recent changes. Also, rearrange output to show .h files before .c (understanding the interface first often makes the implementation easier to follow). Reported-by: Marc-André Lureau <marcandre.lureau@redhat.com> Signed-off-by: Eric Blake <eblake@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-Id: <1457021813-10704-5-git-send-email-eblake@redhat.com>
2016-02-19qapi: Forbid empty unions and useless alternatesEric Blake
Empty unions serve no purpose, and while we compile with gcc which permits them, strict C99 forbids them. We happen to inject a dummy 'void *data' member into the C unions that represent QAPI unions and alternates, but we want to get rid of that member (it pollutes the namespace for no good reason), which would leave us with an empty union if the user didn't provide any branches. While empty structs make sense in QAPI, empty unions don't add any expressiveness to the QMP language. So prohibit them at parse time. Update the documentation and testsuite to match. Note that the documentation already mentioned that alternates should have "two or more JSON data types"; so this also fixes the code to enforce that. However, we have existing uses of a union type with only one branch, so the 2-or-more strictness is intentionally limited to alternates. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1455778109-6278-3-git-send-email-eblake@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2015-12-17qapi: Simplify visiting of alternate typesEric Blake
Previously, working with alternates required two lookup arrays and some indirection: for type Foo, we created Foo_qtypes[] which maps each qtype to a value of the generated FooKind enum, then look up that value in FooKind_lookup[] like we do for other union types. This has a couple of subtle bugs. First, the generator was creating a call with a parameter '(int *) &(*obj)->type' where type is an enum type; this is unsafe if the compiler chooses to store the enum type in a different size than int, where assigning through the wrong size pointer can corrupt data or cause a SIGBUS. Related bug, not not fixed in this patch: qapi-visit.py's gen_visit_enum() generates a cast of its enum * argument to int *. Marked FIXME. Second, since the values of the FooKind enum start at zero, all entries of the Foo_qtypes[] array that were not explicitly initialized will map to the same branch of the union as the first member of the alternate, rather than triggering a desired failure in visit_get_next_type(). Fortunately, the bug seldom bites; the very next thing the input visitor does is try to parse the incoming JSON with the wrong parser, which normally fails; the output visitor is not used with a C struct in that state, and the dealloc visitor has nothing to clean up (so there is no leak). However, the second bug IS observable in one case: parsing an integer causes unusual behavior in an alternate that contains at least a 'number' member but no 'int' member, because the 'number' parser accepts QTYPE_QINT in addition to the expected QTYPE_QFLOAT (that is, since 'int' is not a member, the type QTYPE_QINT accidentally maps to FooKind 0; if this enum value is the 'number' branch the integer parses successfully, but if the 'number' branch is not first, some other branch tries to parse the integer and rejects it). A later patch will worry about fixing alternates to always parse all inputs that a non-alternate 'number' would accept, for now this is still marked FIXME in the updated test-qmp-input-visitor.c, to merely point out that new undesired behavior of 'ans' matches the existing undesired behavior of 'asn'. This patch fixes the default-initialization bug by deleting the indirection, and modifying get_next_type() to directly assign a QTypeCode parameter. This in turn fixes the type-casting bug, as we are no longer casting a pointer to enum to a questionable size. There is no longer a need to generate an implicit FooKind enum associated with the alternate type (since the QMP wire format never uses the stringized counterparts of the C union member names). Since the updated visit_get_next_type() does not know which qtypes are expected, the generated visitor is modified to generate an error statement if an unexpected type is encountered. Callers now have to know the QTYPE_* mapping when looking at the discriminator; but so far, only the testsuite was even using the C struct of an alternate types. I considered the possibility of keeping the internal enum FooKind, but initialized differently than most generated arrays, as in: typedef enum FooKind { FOO_KIND_A = QTYPE_QDICT, FOO_KIND_B = QTYPE_QINT, } FooKind; to create nicer aliases for knowing when to use foo->a or foo->b when inspecting foo->type; but it turned out to add too much complexity, especially without a client. There is a user-visible side effect to this change, but I consider it to be an improvement. Previously, the invalid QMP command: {"execute":"blockdev-add", "arguments":{"options": {"driver":"raw", "id":"a", "file":true}}} failed with: {"error": {"class": "GenericError", "desc": "Invalid parameter type for 'file', expected: QDict"}} (visit_get_next_type() succeeded, and the error comes from the visit_type_BlockdevOptions() expecting {}; there is no mention of the fact that a string would also work). Now it fails with: {"error": {"class": "GenericError", "desc": "Invalid parameter type for 'file', expected: BlockdevRef"}} (the error when the next type doesn't match any expected types for the overall alternate). Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1449033659-25497-5-git-send-email-eblake@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2015-12-17qapi: Convert QType into QAPI built-in enum typeEric Blake
What's more meta than using qapi to define qapi? :) Convert QType into a full-fledged[*] builtin qapi enum type, so that a subsequent patch can then use it as the discriminator type of qapi alternate types. Fortunately, the judicious use of 'prefix' in the qapi definition avoids churn to the spelling of the enum constants. To avoid circular definitions, we have to flip the order of inclusion between "qobject.h" vs. "qapi-types.h". Back in commit 28770e0, we had the latter include the former, so that we could use 'QObject *' for our implementation of 'any'. But that usage also works with only a forward declaration, whereas the definition of QObject requires QType to be a complete type. [*] The type has to be builtin, rather than declared in qapi/common.json, because we want to use it for alternates even when common.json is not included. But since it is the first builtin enum type, we have to add special cases to qapi-types and qapi-visit to only emit definitions once, even when two qapi files are being compiled into the same binary (the way we already handled builtin list types like 'intList'). We may need to revisit how multiple qapi files share common types, but that's a project for another day. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1449033659-25497-4-git-send-email-eblake@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2015-12-17qapi: Don't let implicit enum MAX member collideEric Blake
Now that we guarantee the user doesn't have any enum values beginning with a single underscore, we can use that for our own purposes. Renaming ENUM_MAX to ENUM__MAX makes it obvious that the sentinel is generated. This patch was mostly generated by applying a temporary patch: |diff --git a/scripts/qapi.py b/scripts/qapi.py |index e6d014b..b862ec9 100644 |--- a/scripts/qapi.py |+++ b/scripts/qapi.py |@@ -1570,6 +1570,7 @@ const char *const %(c_name)s_lookup[] = { | max_index = c_enum_const(name, 'MAX', prefix) | ret += mcgen(''' | [%(max_index)s] = NULL, |+// %(max_index)s | }; | ''', | max_index=max_index) then running: $ cat qapi-{types,event}.c tests/test-qapi-types.c | sed -n 's,^// \(.*\)MAX,s|\1MAX|\1_MAX|g,p' > list $ git grep -l _MAX | xargs sed -i -f list The only things not generated are the changes in scripts/qapi.py. Rejecting enum members named 'MAX' is now useless, and will be dropped in the next patch. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1447836791-369-23-git-send-email-eblake@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> [Rebased to current master, commit message tweaked] Signed-off-by: Markus Armbruster <armbru@redhat.com>
2015-12-17qapi: Tighten the regex on valid namesEric Blake
We already documented that qapi names should match specific patterns (such as starting with a letter unless it was an enum value or a downstream extension). Tighten that from a suggestion into a hard requirement, which frees up names beginning with a single underscore for qapi internal usage. The tighter regex doesn't forbid everything insane that a user could provide (for example, a user could name a type 'Foo-lookup' to collide with the generated 'Foo_lookup[]' for an enum 'Foo'), but does a good job at protecting the most obvious uses, and also happens to reserve single leading underscore for later use. The handling of enum values starting with a digit is tricky: commit 9fb081e introduced a subtle bug by using c_name() on a munged value, which would allow an enum to include the member 'q-int' in spite of our reservation. Furthermore, munging with a leading '_' would fail our tighter regex. So fix it by only munging for leading digits (which are never ticklish in c_name()) and by using a different prefix (I picked 'D', although any letter should do). Add new tests, reserved-member-underscore and reserved-enum-q, to demonstrate the tighter checking. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1447836791-369-22-git-send-email-eblake@redhat.com> Message-Id: <1447883135-18020-1-git-send-email-eblake@redhat.com> [Eric's fixup squashed in] Signed-off-by: Markus Armbruster <armbru@redhat.com>
2015-11-17qapi: Document introspection stability considerationsEric Blake
We are not ready (and might never be ready) to declare introspection stable between releases. Clients written to control multiple versions of qemu, and desiring to know whether a particular member is supported for a given command, must be prepared to locate that member in spite of qapi changes that may affect the member's location or type within the overall object, even though such changes did not break QMP wire back-compatibility. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1447264202-19554-1-git-send-email-eblake@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2015-11-10qapi-introspect: Document lack of sortingEric Blake
qapi-code-gen.txt already claims that types, commands, and events share a common namespace; set this in stone by further documenting that our introspection output will never have collisions with the same name tied to more than one meta-type. Our largest QMP enum currently has 125 values, our largest object type has 27 members, and the mean for each is less than 10. These sizes are small enough that the per-element overhead of O(log n) binary searching probably outweighs the speed possible with direct O(n) linear searching (a better algorithm with more overhead will only beat a leaner naive algorithm only as you scale to larger input sizes). Arguably, the overall SchemaInfo array could be sorted by name; there, we currently have 531 entities, large enough for a binary search to be faster than linear. However, remember that we have mutually-recursive types, which means there is no topological ordering that will allow clients to learn all information about that type in a single linear pass; thus clients will want to do random access over the data, and they will probably read the introspection output into a hashtable for O(1) lookup rather than O(log n) binary searching, at which point, pre-sorting our introspection output doesn't help the client. It doesn't help that sorting can be subjective if you introduce locales into the mix (I'm not experienced enough with Python to know for sure, but at least it looks like it defaults to sorting in the C locale even when run under a different locale). And while our current introspection output is deterministic (because we visit entities in a sorted order), we may want to change that order in the future (such as using OrderedDict to stick to .json declaration order). For these reasons, we simply document that clients should not rely on any particular order of items in introspection output. And since it is now a documented part of the contract, we have the freedom to later rearrange output if needed, without worrying about breaking well-written clients. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1446791754-23823-13-git-send-email-eblake@redhat.com> [Commit message tweaked] Signed-off-by: Markus Armbruster <armbru@redhat.com>
2015-11-10qapi: Provide nicer array names in introspectionEric Blake
For the sake of humans reading introspection output, it is nice to have the name of implicit array types be recognizable as arrays of the underlying type. However, while this patch allows humans to skip from a command with return type "[123]" straight to the definition of type "123" without having to first inspect type "[123]", document that this shortcut should not be taken by client apps. This makes the resulting introspection string slightly larger by default (just over 200 bytes), but it's in the noise (less than 0.3% of the overall 70k size of 'query-qmp-capabilities'). Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1446791754-23823-12-git-send-email-eblake@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2015-11-02qapi: Reserve 'q_*' and 'has_*' member namesEric Blake
c_name() produces names starting with 'q_' when protecting a dictionary member name that would fail to directly compile, but in doing so can cause clashes with any member name already beginning with 'q-' or 'q_'. Likewise, we create a C name 'has_' for any optional member that can clash with any member name beginning with 'has-' or 'has_'. Technically, rather than blindly reserving the namespace, we could try to complain about user names only when an actual collision occurs, or even teach c_name() how to munge names to avoid collisions. But it is not trivial, especially when collisions can occur across multiple types (such as via inheritance or flat unions). Besides, no existing .json files are trying to use these names. So it's easier to just outright forbid the potential for collision. We can always relax things in the future if a real need arises for QMP to express member names that have been forbidden here. 'has_' only has to be reserved for struct/union member names, while 'q_' is reserved everywhere (matching the fact that only members can be optional, while we use c_name() for munging both members and entities). Note that we could relax 'q_' restrictions on entities independently from member names; for example, c_name('qmp_' + 'unix') would result in a different function name than our current 'qmp_' + c_name('unix'). Update and add tests to cover the new error messages. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1445898903-12082-6-git-send-email-eblake@redhat.com> [Consistently pass protect=False to c_name(); commit message tweaked slightly] Signed-off-by: Markus Armbruster <armbru@redhat.com>
2015-11-02qapi: Reserve '*List' type names for list typesEric Blake
Type names ending in 'List' can clash with qapi list types in generated C. We don't currently use such names. It is easier to outlaw them now than to worry about how to resolve such a clash in the future. For precedence, see commit 4dc2e69, which did the same for names ending in 'Kind' versus implicit enum types for qapi unions. Update the testsuite to match. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1445898903-12082-5-git-send-email-eblake@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2015-10-12qapi: Consistent generated code: prefer visitor 'v'Eric Blake
We had some pointless differences in the generated code for visit, command marshalling, and events; unifying them makes it easier for future patches to consolidate to common helper functions. This is one patch of a series to clean up these differences. This patch names the local visitor variable 'v' rather than 'm'. Related objects, such as 'QapiDeallocVisitor', are also named by their initials instead of an unrelated leading m. No change in semantics to the generated code. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1443565276-4535-12-git-send-email-eblake@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2015-10-12qapi: Consistent generated code: prefer error 'err'Eric Blake
We had some pointless differences in the generated code for visit, command marshalling, and events; unifying them makes it easier for future patches to consolidate to common helper functions. This is one patch of a series to clean up these differences. This patch consistently names the local error variable 'err' rather than 'local_err'. No change in semantics to the generated code. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1443565276-4535-11-git-send-email-eblake@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2015-09-21qapi-introspect: Hide type namesMarkus Armbruster
To eliminate the temptation for clients to look up types by name (which are not ABI), replace all type names by meaningless strings. Reduces output of query-schema by 13 out of 85KiB. As a debugging aid, provide option -u to suppress the hiding. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <1442401589-24189-27-git-send-email-armbru@redhat.com>
2015-09-21qapi: New QMP command query-qmp-schema for QMP introspectionMarkus Armbruster
qapi/introspect.json defines the introspection schema. It's designed for QMP introspection, but should do for similar uses, such as QGA. The introspection schema does not reflect all the rules and restrictions that apply to QAPI schemata. A valid QAPI schema has an introspection value conforming to the introspection schema, but the converse is not true. Introspection lowers away a number of schema details, and makes implicit things explicit: * The built-in types are declared with their JSON type. All integer types are mapped to 'int', because how many bits we use internally is an implementation detail. It could be pressed into external interface service as very approximate range information, but that's a bad idea. If we need range information, we better do it properly. * Implicit type definitions are made explicit, and given auto-generated names: - Array types, named by appending "List" to the name of their element type, like in generated C. - The enumeration types implicitly defined by simple union types, named by appending "Kind" to the name of their simple union type, like in generated C. - Types that don't occur in generated C. Their names start with ':' so they don't clash with the user's names. * All type references are by name. * The struct and union types are generalized into an object type. * Base types are flattened. * Commands take a single argument and return a single result. Dictionary argument or list result is an implicit type definition. The empty object type is used when a command takes no arguments or produces no results. The argument is always of object type, but the introspection schema doesn't reflect that. The 'gen': false directive is omitted as implementation detail. The 'success-response' directive is omitted as well for now, even though it's not an implementation detail, because it's not used by QMP. * Events carry a single data value. Implicit type definition and empty object type use, just like for commands. The value is of object type, but the introspection schema doesn't reflect that. * Types not used by commands or events are omitted. Indirect use counts as use. * Optional members have a default, which can only be null right now Instead of a mandatory "optional" flag, we have an optional default. No default means mandatory, default null means optional without default value. Non-null is available for optional with default (possible future extension). * Clients should *not* look up types by name, because type names are not ABI. Look up the command or event you're interested in, then follow the references. TODO Should we hide the type names to eliminate the temptation? New generator scripts/qapi-introspect.py computes an introspection value for its input, and generates a C variable holding it. It can generate awfully long lines. Marked TODO. A new test-qmp-input-visitor test case feeds its result for both tests/qapi-schema/qapi-schema-test.json and qapi-schema.json to a QmpInputVisitor to verify it actually conforms to the schema. New QMP command query-qmp-schema takes its return value from that variable. Its reply is some 85KiBytes for me right now. If this turns out to be too much, we have a couple of options: * We can use shorter names in the JSON. Not the QMP style. * Optionally return the sub-schema for commands and events given as arguments. Right now qmp_query_schema() sends the string literal computed by qmp-introspect.py. To compute sub-schema at run time, we'd have to duplicate parts of qapi-introspect.py in C. Unattractive. * Let clients cache the output of query-qmp-schema. It changes only on QEMU upgrades, i.e. rarely. Provide a command query-qmp-schema-hash. Clients can have a cache indexed by hash, and re-query the schema only when they don't have it cached. Even simpler: put the hash in the QMP greeting. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
2015-09-21qapi: Pseudo-type '**' is now unused, drop itMarkus Armbruster
'gen': false needs to stay for now, because netdev_add is still using it. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Daniel P. Berrange <berrange@redhat.com> Message-Id: <1442401589-24189-25-git-send-email-armbru@redhat.com>
2015-09-21qapi-schema: Fix up misleading specification of netdev_addMarkus Armbruster
It doesn't take a 'props' argument, let alone one in the format "NAME=VALUE,..." The bogus arguments specification doesn't matter due to 'gen': false. Clean it up to be incomplete rather than wrong, and document the incompleteness. While there, improve netdev_add usage example in the manual: add a device option to show how it's done. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Daniel P. Berrange <berrange@redhat.com> Message-Id: <1442401589-24189-24-git-send-email-armbru@redhat.com>
2015-09-21qapi: Introduce a first class 'any' typeMarkus Armbruster
It's first class, because unlike '**', it actually works, i.e. doesn't require 'gen': false. '**' will go away next. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
2015-09-21qapi: Improve built-in type documentationMarkus Armbruster
Clarify how they map to JSON. Add how they map to C. Fix the reference to StringInputVisitor. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Daniel P. Berrange <berrange@redhat.com> Message-Id: <1442401589-24189-20-git-send-email-armbru@redhat.com>
2015-09-21qapi-commands: De-duplicate output marshaling functionsMarkus Armbruster
gen_marshal_output() uses its parameter name only for name of the generated function. Name it after the type being marshaled instead of its caller, and drop duplicates. Saves 7 copies of qmp_marshal_output_int() in qemu-ga, and one copy of qmp_marshal_output_str() in qemu-system-*. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Daniel P. Berrange <berrange@redhat.com> Message-Id: <1442401589-24189-19-git-send-email-armbru@redhat.com>
2015-09-21qapi: Rename qmp_marshal_input_FOO() to qmp_marshal_FOO()Markus Armbruster
These functions marshal both input and output. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Daniel P. Berrange <berrange@redhat.com> Message-Id: <1442401589-24189-17-git-send-email-armbru@redhat.com>
2015-09-21qapi: Clean up after recent conversions to QAPISchemaVisitorMarkus Armbruster
Generate just 'FOO' instead of 'struct FOO' when possible. Drop helper functions that are now unused. Make pep8 and pylint reasonably happy. Rename generate_FOO() functions to gen_FOO() for consistency. Use more consistent and sensible variable names. Consistently use c_ for mapping keys when their value is a C identifier or type. Simplify gen_enum() and gen_visit_union() Consistently use single quotes for C text string literals. Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-Id: <1442401589-24189-14-git-send-email-armbru@redhat.com> Reviewed-by: Daniel P. Berrange <berrange@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
2015-09-21qapi: De-duplicate enum code generationMarkus Armbruster
Duplicated in commit 21cd70d. Yes, we can't import qapi-types, but that's no excuse. Move the helpers from qapi-types.py to qapi.py, and replace the duplicates in qapi-event.py. The generated event enumeration type's lookup table becomes const-correct (see commit 2e4450f), and uses explicit indexes instead of relying on order (see commit 912ae9c). Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-Id: <1442401589-24189-10-git-send-email-armbru@redhat.com> Reviewed-by: Daniel P. Berrange <berrange@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
2015-09-21qapi-types: Convert to QAPISchemaVisitor, fixing flat unionsMarkus Armbruster
Fixes flat unions to get the base's base members. Test case is from commit 2fc0043, in qapi-schema-test.json: { 'union': 'UserDefFlatUnion', 'base': 'UserDefUnionBase', 'discriminator': 'enum1', 'data': { 'value1' : 'UserDefA', 'value2' : 'UserDefB', 'value3' : 'UserDefB' } } { 'struct': 'UserDefUnionBase', 'base': 'UserDefZero', 'data': { 'string': 'str', 'enum1': 'EnumOne' } } { 'struct': 'UserDefZero', 'data': { 'integer': 'int' } } Patch's effect on UserDefFlatUnion: struct UserDefFlatUnion { /* Members inherited from UserDefUnionBase: */ + int64_t integer; char *string; EnumOne enum1; /* Own members: */ union { /* union tag is @enum1 */ void *data; UserDefA *value1; UserDefB *value2; UserDefB *value3; }; }; Flat union visitors remain broken. They'll be fixed next. Code is generated in a different order now, but that doesn't matter. The two guards QAPI_TYPES_BUILTIN_STRUCT_DECL and QAPI_TYPES_BUILTIN_CLEANUP_DECL are replaced by just QAPI_TYPES_BUILTIN. Two ugly special cases for simple unions now stand out like sore thumbs: 1. The type tag is named 'type' everywhere, except in generated C, where it's 'kind'. 2. QAPISchema lowers simple unions to semantically equivalent flat unions. However, the C generated for a simple unions differs from the C generated for its equivalent flat union, and we therefore need special code to preserve that pointless difference for now. Mark both TODO. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Daniel P. Berrange <berrange@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
2015-09-15qapi: allow override of default enum prefix namingDaniel P. Berrange
The camel_to_upper() method applies some heuristics to turn a mixed case type name into an all-uppercase name. This is used for example, to generate enum constant name prefixes. The heuristics don't also generate a satisfactory name though. eg { 'enum': 'QCryptoTLSCredsEndpoint', 'data': ['client', 'server']} Results in Q_CRYPTOTLS_CREDS_ENDPOINT_CLIENT. This has an undesirable _ after the initial Q and is missing an _ between the CRYPTO & TLS strings. Rather than try to add more and more heuristics to try to cope with this, simply allow the QAPI schema to specify the desired enum constant prefix explicitly. eg { 'enum': 'QCryptoTLSCredsEndpoint', 'prefix': 'QCRYPTO_TLS_CREDS_ENDPOINT', 'data': ['client', 'server']} Now gives the QCRYPTO_TLS_CREDS_ENDPOINT_CLIENT name. Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2015-09-04docs/qapi-code-gen.txt: Fix QAPI schema examplesMarkus Armbruster
Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
2015-09-04qapi: Generated code cleanupMarkus Armbruster
Clean up white-space, brace placement, and superfluous #ifdef QAPI_TYPES_BUILTIN_CLEANUP_DEF. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
2015-09-04qapi-commands: Drop useless initializationMarkus Armbruster
In generated command handlers, the assignment to retval dominates its only use. Therefore, its initialization is useless. Drop it. Suggested-by: Eric Blake <eblake@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
2015-09-04qapi: Command returning anonymous type doesn't work, outlawMarkus Armbruster
Reproducer: with { 'command': 'user_def_cmd4', 'returns': { 'a': 'int' } } added to qapi-schema-test.json, qapi-commands.py dies when it tries to generate the command handler function Traceback (most recent call last): File "/work/armbru/qemu/scripts/qapi-commands.py", line 359, in <module> ret = generate_command_decl(cmd['command'], arglist, ret_type) + "\n" File "/work/armbru/qemu/scripts/qapi-commands.py", line 29, in generate_command_decl ret_type=c_type(ret_type), name=c_name(name), File "/work/armbru/qemu/scripts/qapi.py", line 927, in c_type assert isinstance(value, str) and value != "" AssertionError because the return type doesn't exist. Simply outlaw this usage, and drop or dumb down test cases accordingly. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
2015-09-04qapi: Fix to reject union command and event argumentsMarkus Armbruster
A command's or event's 'data' must be a struct type, given either as a dictionary, or as struct type name. Commit dd883c6 tightened the checking there, but not enough: we still accept 'union'. Fix to reject it. We may want to support union types there, but we'll have to extend qapi-commands.py and qapi-events.py for it. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
2015-09-04qapi-event: Clean up how name of enum QAPIEvent is madeMarkus Armbruster
Use c_name() instead of ad hoc code. Doesn't upcase the -p prefix, which is an improvement in my book. Unbreaks prefix containing '.', but other funny characters remain broken. To be fixed next. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
2015-09-04qapi: Clarify docs on including the same file multiple timesMarkus Armbruster
It's idempotent. While there, update examples to current code. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
2015-06-18qapi: Drop bogus command from docsMarkus Armbruster
Commit 87a560c4 added it in the wrong place. Commit 59a2c4ce added it in the right place, but didn't remove it from the wrong place. Do that now. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
2015-05-14qapi: Turn generators' mandatory option -i into an argumentMarkus Armbruster
Mandatory option is silly, and the error handling is missing: the programs crash when -i isn't supplied. Make it an argument, and check it properly. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
2015-05-05qapi: Tweak doc references to QMP when QGA is also meantEric Blake
We have more than one qapi schema in use by more than one protocol. Add a new term 'Client JSON Protocol' for use throughout the document, to avoid confusion on whether something refers only to QMP and not QGA. Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2015-05-05qapi: Document 'struct' metatypeEric Blake
Referring to "type" as both a meta-type (built-in, enum, union, alternate, or struct) and a specific type (the name that the schema uses for declaring structs) is confusing. Now that the generator accepts 'struct' as a synonym for 'type', update all documentation to use saner wording. Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2015-05-05qapi: Document new 'alternate' meta-typeEric Blake
The next patch will quit special-casing "'union':'Foo', 'discriminator':{}" and instead use "'alternate':'Foo'". Separating docs from implementation makes it easier to focus on wording without holding up code. In particular, making alternate a separate type makes for a nice type hierarchy: /-------- meta-type ------\ / | \ simple types alternate complex types | | | | built-in enum type(struct) union | \ / / \ numeric string simple flat A later patch will then clean up 'type' vs. 'struct' confusion. Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2015-05-05qapi: Document type-safety considerationsEric Blake
Go into more details about the various types of valid expressions in a qapi schema, including tweaks to document fixes being done later in the current patch series. Also fix some stale and missing documentation in the QMP specification. Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2015-05-05qapi: Add copyright declaration on docsEric Blake
While our top-level COPYING with its GPLv2+ license applies to any documentation file that omits explicit instructions, these days it's better to be a good example of calling out our intentions. Correct use of GPL requires the use of a copyright statement, so I'm adding notice to two QAPI documents, by attributing these files to the initial authors and major contributors. I used: $ git blame --line-porcelain $file \ | sed -n 's/^author //p' | sort | uniq -c | sort -rn to determine authorship of these two files. qmp-spec.txt blames entirely to Red Hat (easy, since my contribution falls in that category); while qapi-code-gen.txt has multiple contributors representing multiple entities. But since it was originally supplied by Michael Roth, the notice I added there copies the notice he has used in other files. As there is no intended change in license from the implicit one previously present from the top level, I have not bothered to CC other contributors; if we want to weaken things to something looser (such as LGPL) so that there is no question that someone re-implementing the spec is not forced to use GPL, that would be a different commit. CC: Michael Roth <mdroth@linux.vnet.ibm.com> Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2014-09-26qapi: Update docs given recent event, spacing fixesEric Blake
Commit 21cd70d added event support but didn't document what the generated code looks like. Commit 05dfb26 removed some unwanted spaces in the generated code, but didn't reflect those changes into the documentation. Finally, the docs start with a big disclaimer about QMP not using QAPI yet, which feels rather stale. Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
2014-06-27qapi script: clean up in scriptsWenchao Xia
This patch improve docs and uses c_type(argentry, is_param=True) in script. Signed-off-by: Wenchao Xia <wenchaoqemu@gmail.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2014-06-23qapi script: add event supportWenchao Xia
qapi-event.py will parse the schema and generate qapi-event.c, then the API in qapi-event.c can be used to handle events in qemu code. All API have prefix "qapi_event". The script mainly includes two parts: generate API for each event define, generate an enum type for all defined events. Since in some cases the real emit behavior may change, for example, qemu-img would not send a event, a callback layer is used to control the behavior. As a result, the stubs at compile time can be saved, the binding of block layer code and monitor code will become looser. Signed-off-by: Wenchao Xia <wenchaoqemu@gmail.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2014-05-16qapi: skip redundant includesBenoît Canet
The purpose of this change is to help create a json file containing common definitions; each bit of generated C code must be emitted only one time. A second history global to all QAPISchema instances has been added to detect when a file is included more than one time and skip these includes. It does not act as a stack and the changes made to it by the __init__ function are propagated back to the caller so it's really a global state. Signed-off-by: Benoit Canet <benoit@irqsave.net> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2014-05-15qapi: Show qapi-commands.py invocation in qapi-code-gen.txtMarkus Armbruster
While there, pare down the shell prompts. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2014-05-15qapi: Replace uncommon use of the error API by the common oneMarkus Armbruster
We commonly use the error API like this: err = NULL; foo(..., &err); if (err) { goto out; } bar(..., &err); Every error source is checked separately. The second function is only called when the first one succeeds. Both functions are free to pass their argument to error_set(). Because error_set() asserts no error has been set, this effectively means they must not be called with an error set. The qapi-generated code uses the error API differently: // *errp was initialized to NULL somewhere up the call chain frob(..., errp); gnat(..., errp); Errors accumulate in *errp: first error wins, subsequent errors get dropped. To make this work, the second function does nothing when called with an error set. Requires non-null errp, or else the second function can't see the first one fail. This usage has also bled into visitor tests, and two device model object property getters rtc_get_date() and balloon_stats_get_all(). With the "accumulate" technique, you need fewer error checks in callers, and buy that with an error check in every callee. Can be nice. However, mixing the two techniques is confusing. You can't use the "accumulate" technique with functions designed for the "check separately" technique. You can use the "check separately" technique with functions designed for the "accumulate" technique, but then error_set() can't catch you setting an error more than once. Standardize on the "check separately" technique for now, because it's overwhelmingly prevalent. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2014-05-15qapi: Normalize marshalling's visitor initialization and cleanupMarkus Armbruster
Input and output marshalling functions do it differently. Change them to work the same: initialize the I/O visitor, use it, clean it up, initialize the dealloc visitor, use it, clean it up. This delays dealloc visitor initialization in output marshalling functions, and input visitor cleanup in input marshalling functions. No functional change, but the latter will be convenient when I change the error handling. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2014-05-15qapi: Update qapi-code-gen.txt example to match current codeMarkus Armbruster
Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2014-05-09qapi: Document optional arguments' backwards compatibilityEric Blake
Signed-off-by: Eric Blake <eblake@redhat.com> Signed-off-by: Fam Zheng <famz@redhat.com> Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2014-05-08qapi: Add a primitive to include other files from a QAPI schema fileLluís Vilanova
The primitive uses JSON syntax, and include paths are relative to the file using the directive: { 'include': 'path/to/file.json' } Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2014-05-08qapi: Use an explicit input fileLluís Vilanova
Use an explicit input file on the command-line instead of reading from standard input. It also outputs the proper file name when there's an error. Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>