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unicorn/qemu/include/qapi/visitor-impl.h

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import
2015-08-21 07:04:50 +00:00
/*
* Core Definitions for QAPI Visitor implementations
*
qapi: Drop unused error argument for list and implicit struct No backend was setting an error when ending the visit of a list or implicit struct, or when moving to the next list node. Make the callers a bit easier to follow by making this a part of the contract, and removing the errp argument - callers can then unconditionally end an object as part of cleanup without having to think about whether a second error is dominated by a first, because there is no second error. A later patch will then tackle the larger task of splitting visit_end_struct(), which can indeed set an error. Backports commit 08f9541dec51700abef0c37994213164ca4e4fc9 from qemu
2018-02-19 17:58:24 +00:00
* Copyright (C) 2012-2016 Red Hat, Inc.
import
2015-08-21 07:04:50 +00:00
*
* Author: Paolo Bonizni <pbonzini@redhat.com>
*
* This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
* See the COPYING.LIB file in the top-level directory.
*
*/
#ifndef QAPI_VISITOR_IMPL_H
#define QAPI_VISITOR_IMPL_H
#include "qapi/error.h"
#include "qapi/visitor.h"
struct Visitor
{
/* Must be set */
qapi: Swap 'name' in visit_* callbacks to match public API As explained in the previous patches, matching argument order of 'name, &value' to JSON's "name":value makes sense. However, while the last two patches were easy with Coccinelle, I ended up doing this one all by hand. Now all the visitor callbacks match the main interface. The compiler is able to enforce that all clients match the changed interface in visitor-impl.h, even where two pointers are being swapped, because only one of the two pointers is const (if that were not the case, then C's looseness on treating 'char *' like 'void *' would have made review a bit harder). Backports commit 0b2a0d6bb2446060944061e53e87d0c7addede79 from qemu
2018-02-20 04:28:33 +00:00
void (*start_struct)(Visitor *v, const char *name, void **obj,
qapi: Drop unused 'kind' for struct/enum visit visit_start_struct() and visit_type_enum() had a 'kind' argument that was usually set to either the stringized version of the corresponding qapi type name, or to NULL (although some clients didn't even get that right). But nothing ever used the argument. It's even hard to argue that it would be useful in a debugger, as a stack backtrace also tells which type is being visited. Therefore, drop the 'kind' argument as dead. Backports commit 337283dffbb5ad5860ed00408a5fd0665c21be07 from qemu
2018-02-20 04:42:59 +00:00
size_t size, Error **errp);
import
2015-08-21 07:04:50 +00:00
void (*end_struct)(Visitor *v, Error **errp);
void (*start_implicit_struct)(Visitor *v, void **obj, size_t size,
Error **errp);
qapi: Drop unused error argument for list and implicit struct No backend was setting an error when ending the visit of a list or implicit struct, or when moving to the next list node. Make the callers a bit easier to follow by making this a part of the contract, and removing the errp argument - callers can then unconditionally end an object as part of cleanup without having to think about whether a second error is dominated by a first, because there is no second error. A later patch will then tackle the larger task of splitting visit_end_struct(), which can indeed set an error. Backports commit 08f9541dec51700abef0c37994213164ca4e4fc9 from qemu
2018-02-19 17:58:24 +00:00
void (*end_implicit_struct)(Visitor *v);
import
2015-08-21 07:04:50 +00:00
void (*start_list)(Visitor *v, const char *name, Error **errp);
qapi: Drop unused error argument for list and implicit struct No backend was setting an error when ending the visit of a list or implicit struct, or when moving to the next list node. Make the callers a bit easier to follow by making this a part of the contract, and removing the errp argument - callers can then unconditionally end an object as part of cleanup without having to think about whether a second error is dominated by a first, because there is no second error. A later patch will then tackle the larger task of splitting visit_end_struct(), which can indeed set an error. Backports commit 08f9541dec51700abef0c37994213164ca4e4fc9 from qemu
2018-02-19 17:58:24 +00:00
GenericList *(*next_list)(Visitor *v, GenericList **list);
void (*end_list)(Visitor *v);
import
2015-08-21 07:04:50 +00:00
qapi: Swap 'name' in visit_* callbacks to match public API As explained in the previous patches, matching argument order of 'name, &value' to JSON's "name":value makes sense. However, while the last two patches were easy with Coccinelle, I ended up doing this one all by hand. Now all the visitor callbacks match the main interface. The compiler is able to enforce that all clients match the changed interface in visitor-impl.h, even where two pointers are being swapped, because only one of the two pointers is const (if that were not the case, then C's looseness on treating 'char *' like 'void *' would have made review a bit harder). Backports commit 0b2a0d6bb2446060944061e53e87d0c7addede79 from qemu
2018-02-20 04:28:33 +00:00
void (*type_enum)(Visitor *v, const char *name, int *obj,
qapi: Drop unused 'kind' for struct/enum visit visit_start_struct() and visit_type_enum() had a 'kind' argument that was usually set to either the stringized version of the corresponding qapi type name, or to NULL (although some clients didn't even get that right). But nothing ever used the argument. It's even hard to argue that it would be useful in a debugger, as a stack backtrace also tells which type is being visited. Therefore, drop the 'kind' argument as dead. Backports commit 337283dffbb5ad5860ed00408a5fd0665c21be07 from qemu
2018-02-20 04:42:59 +00:00
const char *const strings[], Error **errp);
qapi: Simplify visiting of alternate types 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). Backports commit 0426d53c6530606bf7641b83f2b755fe61c280ee from qemu
2018-02-20 02:51:35 +00:00
/* May be NULL; only needed for input visitors. */
qapi: Swap 'name' in visit_* callbacks to match public API As explained in the previous patches, matching argument order of 'name, &value' to JSON's "name":value makes sense. However, while the last two patches were easy with Coccinelle, I ended up doing this one all by hand. Now all the visitor callbacks match the main interface. The compiler is able to enforce that all clients match the changed interface in visitor-impl.h, even where two pointers are being swapped, because only one of the two pointers is const (if that were not the case, then C's looseness on treating 'char *' like 'void *' would have made review a bit harder). Backports commit 0b2a0d6bb2446060944061e53e87d0c7addede79 from qemu
2018-02-20 04:28:33 +00:00
void (*get_next_type)(Visitor *v, const char *name, QType *type,
bool promote_int, Error **errp);
qapi: Prefer type_int64 over type_int in visitors The qapi builtin type 'int' is basically shorthand for the type 'int64'. In fact, since no visitor was providing the optional type_int64() callback, visit_type_int64() was just always falling back to type_int(), cementing the equivalence between the types. However, some visitors are providing a type_uint64() callback. For purposes of code consistency, it is nicer if all visitors use the paired type_int64/type_uint64 names rather than the mismatched type_int/type_uint64. So this patch just renames the signed int callbacks in place, dropping the type_int() callback as redundant, and a later patch will focus on the unsigned int callbacks. Add some FIXMEs to questionable reuse of errp in code touched by the rename, while at it (the reuse works as long as the callbacks don't modify value when setting an error, but it's not a good example to set) - a later patch will then fix those. No change in functionality here, although further cleanups are in the pipeline. Backports commit 4c40314a35816de635e7170eaacdc0c35be83a8a from qemu
2018-02-19 16:53:19 +00:00
/* Must be set. */
qapi: Swap 'name' in visit_* callbacks to match public API As explained in the previous patches, matching argument order of 'name, &value' to JSON's "name":value makes sense. However, while the last two patches were easy with Coccinelle, I ended up doing this one all by hand. Now all the visitor callbacks match the main interface. The compiler is able to enforce that all clients match the changed interface in visitor-impl.h, even where two pointers are being swapped, because only one of the two pointers is const (if that were not the case, then C's looseness on treating 'char *' like 'void *' would have made review a bit harder). Backports commit 0b2a0d6bb2446060944061e53e87d0c7addede79 from qemu
2018-02-20 04:28:33 +00:00
void (*type_int64)(Visitor *v, const char *name, int64_t *obj,
qapi: Prefer type_int64 over type_int in visitors The qapi builtin type 'int' is basically shorthand for the type 'int64'. In fact, since no visitor was providing the optional type_int64() callback, visit_type_int64() was just always falling back to type_int(), cementing the equivalence between the types. However, some visitors are providing a type_uint64() callback. For purposes of code consistency, it is nicer if all visitors use the paired type_int64/type_uint64 names rather than the mismatched type_int/type_uint64. So this patch just renames the signed int callbacks in place, dropping the type_int() callback as redundant, and a later patch will focus on the unsigned int callbacks. Add some FIXMEs to questionable reuse of errp in code touched by the rename, while at it (the reuse works as long as the callbacks don't modify value when setting an error, but it's not a good example to set) - a later patch will then fix those. No change in functionality here, although further cleanups are in the pipeline. Backports commit 4c40314a35816de635e7170eaacdc0c35be83a8a from qemu
2018-02-19 16:53:19 +00:00
Error **errp);
/* Must be set. */
qapi: Swap 'name' in visit_* callbacks to match public API As explained in the previous patches, matching argument order of 'name, &value' to JSON's "name":value makes sense. However, while the last two patches were easy with Coccinelle, I ended up doing this one all by hand. Now all the visitor callbacks match the main interface. The compiler is able to enforce that all clients match the changed interface in visitor-impl.h, even where two pointers are being swapped, because only one of the two pointers is const (if that were not the case, then C's looseness on treating 'char *' like 'void *' would have made review a bit harder). Backports commit 0b2a0d6bb2446060944061e53e87d0c7addede79 from qemu
2018-02-20 04:28:33 +00:00
void (*type_uint64)(Visitor *v, const char *name, uint64_t *obj,
qapi: Make all visitors supply uint64 callbacks Our qapi visitor contract supports multiple integer visitors, but left the type_uint64 visitor as optional (falling back on type_int64); which in turn can lead to awkward behavior with numbers larger than INT64_MAX (the user has to be aware of twos complement, and deal with negatives). This patch does not address the disparity in handling large values as negatives. It merely moves the fallback from uint64 to int64 from the visitor core to the visitors, where the issue can actually be fixed, by implementing the missing type_uint64() callbacks on top of the respective type_int64() callbacks, and with a FIXME comment explaining why that's wrong. With that done, we now have a type_uint64() callback in every driver, so we can make it mandatory from the core. And although the type_int64() callback can cover the entire valid range of type_uint{8,16,32} on valid user input, using type_uint64() to avoid mixed signedness makes more sense. Backports commit f755dea79dc81b0d6a8f6414e0672e165e28d8ba from qemu
2018-02-19 16:57:56 +00:00
Error **errp);
/* Optional; fallback is type_uint64(). */
qapi: Swap 'name' in visit_* callbacks to match public API As explained in the previous patches, matching argument order of 'name, &value' to JSON's "name":value makes sense. However, while the last two patches were easy with Coccinelle, I ended up doing this one all by hand. Now all the visitor callbacks match the main interface. The compiler is able to enforce that all clients match the changed interface in visitor-impl.h, even where two pointers are being swapped, because only one of the two pointers is const (if that were not the case, then C's looseness on treating 'char *' like 'void *' would have made review a bit harder). Backports commit 0b2a0d6bb2446060944061e53e87d0c7addede79 from qemu
2018-02-20 04:28:33 +00:00
void (*type_size)(Visitor *v, const char *name, uint64_t *obj,
qapi: Make all visitors supply uint64 callbacks Our qapi visitor contract supports multiple integer visitors, but left the type_uint64 visitor as optional (falling back on type_int64); which in turn can lead to awkward behavior with numbers larger than INT64_MAX (the user has to be aware of twos complement, and deal with negatives). This patch does not address the disparity in handling large values as negatives. It merely moves the fallback from uint64 to int64 from the visitor core to the visitors, where the issue can actually be fixed, by implementing the missing type_uint64() callbacks on top of the respective type_int64() callbacks, and with a FIXME comment explaining why that's wrong. With that done, we now have a type_uint64() callback in every driver, so we can make it mandatory from the core. And although the type_int64() callback can cover the entire valid range of type_uint{8,16,32} on valid user input, using type_uint64() to avoid mixed signedness makes more sense. Backports commit f755dea79dc81b0d6a8f6414e0672e165e28d8ba from qemu
2018-02-19 16:57:56 +00:00
Error **errp);
/* Must be set. */
qapi: Swap 'name' in visit_* callbacks to match public API As explained in the previous patches, matching argument order of 'name, &value' to JSON's "name":value makes sense. However, while the last two patches were easy with Coccinelle, I ended up doing this one all by hand. Now all the visitor callbacks match the main interface. The compiler is able to enforce that all clients match the changed interface in visitor-impl.h, even where two pointers are being swapped, because only one of the two pointers is const (if that were not the case, then C's looseness on treating 'char *' like 'void *' would have made review a bit harder). Backports commit 0b2a0d6bb2446060944061e53e87d0c7addede79 from qemu
2018-02-20 04:28:33 +00:00
void (*type_bool)(Visitor *v, const char *name, bool *obj, Error **errp);
void (*type_str)(Visitor *v, const char *name, char **obj, Error **errp);
void (*type_number)(Visitor *v, const char *name, double *obj,
import
2015-08-21 07:04:50 +00:00
Error **errp);
qapi: Swap 'name' in visit_* callbacks to match public API As explained in the previous patches, matching argument order of 'name, &value' to JSON's "name":value makes sense. However, while the last two patches were easy with Coccinelle, I ended up doing this one all by hand. Now all the visitor callbacks match the main interface. The compiler is able to enforce that all clients match the changed interface in visitor-impl.h, even where two pointers are being swapped, because only one of the two pointers is const (if that were not the case, then C's looseness on treating 'char *' like 'void *' would have made review a bit harder). Backports commit 0b2a0d6bb2446060944061e53e87d0c7addede79 from qemu
2018-02-20 04:28:33 +00:00
void (*type_any)(Visitor *v, const char *name, QObject **obj,
qapi: Introduce a first class 'any' type It's first class, because unlike '**', it actually works, i.e. doesn't require 'gen': false. '**' will go away next. Backports commit 28770e057f265a4e70bcbdfc2447cce7b5f2dc19 from qemu
2018-02-19 22:45:25 +00:00
Error **errp);
import
2015-08-21 07:04:50 +00:00
qapi: Simplify visits of optional fields None of the visitor callbacks would set an error when testing if an optional field was present; make this part of the interface contract by eliminating the errp argument. The resulting generated code has a nice diff: |- visit_optional(v, &has_fdset_id, "fdset-id", &err); |- if (err) { |- goto out; |- } |+ visit_optional(v, &has_fdset_id, "fdset-id"); | if (has_fdset_id) { | visit_type_int(v, &fdset_id, "fdset-id", &err); | if (err) { | goto out; | } | } Backports commit 5cdc8831a795fb8452d7e34f644202fd724e122a from qemu
2018-02-20 03:00:34 +00:00
/* May be NULL; most useful for input visitors. */
qapi: Swap 'name' in visit_* callbacks to match public API As explained in the previous patches, matching argument order of 'name, &value' to JSON's "name":value makes sense. However, while the last two patches were easy with Coccinelle, I ended up doing this one all by hand. Now all the visitor callbacks match the main interface. The compiler is able to enforce that all clients match the changed interface in visitor-impl.h, even where two pointers are being swapped, because only one of the two pointers is const (if that were not the case, then C's looseness on treating 'char *' like 'void *' would have made review a bit harder). Backports commit 0b2a0d6bb2446060944061e53e87d0c7addede79 from qemu
2018-02-20 04:28:33 +00:00
void (*optional)(Visitor *v, const char *name, bool *present);
import
2015-08-21 07:04:50 +00:00
};
qapi: Swap 'name' in visit_* callbacks to match public API As explained in the previous patches, matching argument order of 'name, &value' to JSON's "name":value makes sense. However, while the last two patches were easy with Coccinelle, I ended up doing this one all by hand. Now all the visitor callbacks match the main interface. The compiler is able to enforce that all clients match the changed interface in visitor-impl.h, even where two pointers are being swapped, because only one of the two pointers is const (if that were not the case, then C's looseness on treating 'char *' like 'void *' would have made review a bit harder). Backports commit 0b2a0d6bb2446060944061e53e87d0c7addede79 from qemu
2018-02-20 04:28:33 +00:00
void input_type_enum(Visitor *v, const char *name, int *obj,
qapi: Drop unused 'kind' for struct/enum visit visit_start_struct() and visit_type_enum() had a 'kind' argument that was usually set to either the stringized version of the corresponding qapi type name, or to NULL (although some clients didn't even get that right). But nothing ever used the argument. It's even hard to argue that it would be useful in a debugger, as a stack backtrace also tells which type is being visited. Therefore, drop the 'kind' argument as dead. Backports commit 337283dffbb5ad5860ed00408a5fd0665c21be07 from qemu
2018-02-20 04:42:59 +00:00
const char *const strings[], Error **errp);
qapi: Swap 'name' in visit_* callbacks to match public API As explained in the previous patches, matching argument order of 'name, &value' to JSON's "name":value makes sense. However, while the last two patches were easy with Coccinelle, I ended up doing this one all by hand. Now all the visitor callbacks match the main interface. The compiler is able to enforce that all clients match the changed interface in visitor-impl.h, even where two pointers are being swapped, because only one of the two pointers is const (if that were not the case, then C's looseness on treating 'char *' like 'void *' would have made review a bit harder). Backports commit 0b2a0d6bb2446060944061e53e87d0c7addede79 from qemu
2018-02-20 04:28:33 +00:00
void output_type_enum(Visitor *v, const char *name, int *obj,
qapi: Drop unused 'kind' for struct/enum visit visit_start_struct() and visit_type_enum() had a 'kind' argument that was usually set to either the stringized version of the corresponding qapi type name, or to NULL (although some clients didn't even get that right). But nothing ever used the argument. It's even hard to argue that it would be useful in a debugger, as a stack backtrace also tells which type is being visited. Therefore, drop the 'kind' argument as dead. Backports commit 337283dffbb5ad5860ed00408a5fd0665c21be07 from qemu
2018-02-20 04:42:59 +00:00
const char *const strings[], Error **errp);
import
2015-08-21 07:04:50 +00:00
#endif
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