dragonpilot - 基於 openpilot 的開源駕駛輔助系統
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// Copyright (c) 2013-2014 Sandstorm Development Group, Inc. and contributors
// Licensed under the MIT License:
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
#ifndef CAPNP_RAW_SCHEMA_H_
#define CAPNP_RAW_SCHEMA_H_
#if defined(__GNUC__) && !defined(CAPNP_HEADER_WARNINGS)
#pragma GCC system_header
#endif
#include "common.h" // for uint and friends
#if _MSC_VER
#include <atomic>
#endif
namespace capnp {
namespace _ { // private
struct RawSchema;
struct RawBrandedSchema {
// Represents a combination of a schema and bindings for its generic parameters.
//
// Note that while we generate one `RawSchema` per type, we generate a `RawBrandedSchema` for
// every _instance_ of a generic type -- or, at least, every instance that is actually used. For
// generated-code types, we use template magic to initialize these.
const RawSchema* generic;
// Generic type which we're branding.
struct Binding {
uint8_t which; // Numeric value of one of schema::Type::Which.
bool isImplicitParameter;
// For AnyPointer, true if it's an implicit method parameter.
uint16_t listDepth; // Number of times to wrap the base type in List().
uint16_t paramIndex;
// For AnyPointer. If it's a type parameter (scopeId is non-zero) or it's an implicit parameter
// (isImplicitParameter is true), then this is the parameter index. Otherwise this is a numeric
// value of one of schema::Type::AnyPointer::Unconstrained::Which.
union {
const RawBrandedSchema* schema; // for struct, enum, interface
uint64_t scopeId; // for AnyPointer, if it's a type parameter
};
Binding() = default;
inline constexpr Binding(uint8_t which, uint16_t listDepth, const RawBrandedSchema* schema)
: which(which), isImplicitParameter(false), listDepth(listDepth), paramIndex(0),
schema(schema) {}
inline constexpr Binding(uint8_t which, uint16_t listDepth,
uint64_t scopeId, uint16_t paramIndex)
: which(which), isImplicitParameter(false), listDepth(listDepth), paramIndex(paramIndex),
scopeId(scopeId) {}
inline constexpr Binding(uint8_t which, uint16_t listDepth, uint16_t implicitParamIndex)
: which(which), isImplicitParameter(true), listDepth(listDepth),
paramIndex(implicitParamIndex), scopeId(0) {}
};
struct Scope {
uint64_t typeId;
// Type ID whose parameters are being bound.
const Binding* bindings;
uint bindingCount;
// Bindings for those parameters.
bool isUnbound;
// This scope is unbound, in the sense of SchemaLoader::getUnbound().
};
const Scope* scopes;
// Array of enclosing scopes for which generic variables have been bound, sorted by type ID.
struct Dependency {
uint location;
const RawBrandedSchema* schema;
};
const Dependency* dependencies;
// Map of branded schemas for dependencies of this type, given our brand. Only dependencies that
// are branded are included in this map; if a dependency is missing, use its `defaultBrand`.
uint32_t scopeCount;
uint32_t dependencyCount;
enum class DepKind {
// Component of a Dependency::location. Specifies what sort of dependency this is.
INVALID,
// Mostly defined to ensure that zero is not a valid location.
FIELD,
// Binding needed for a field's type. The index is the field index (NOT ordinal!).
METHOD_PARAMS,
// Bindings needed for a method's params type. The index is the method number.
METHOD_RESULTS,
// Bindings needed for a method's results type. The index is the method ordinal.
SUPERCLASS,
// Bindings needed for a superclass type. The index is the superclass's index in the
// "extends" list.
CONST_TYPE
// Bindings needed for the type of a constant. The index is zero.
};
static inline uint makeDepLocation(DepKind kind, uint index) {
// Make a number representing the location of a particular dependency within its parent
// schema.
return (static_cast<uint>(kind) << 24) | index;
}
class Initializer {
public:
virtual void init(const RawBrandedSchema* generic) const = 0;
};
const Initializer* lazyInitializer;
// Lazy initializer, invoked by ensureInitialized().
inline void ensureInitialized() const {
// Lazy initialization support. Invoke to ensure that initialization has taken place. This
// is required in particular when traversing the dependency list. RawSchemas for compiled-in
// types are always initialized; only dynamically-loaded schemas may be lazy.
#if __GNUC__
const Initializer* i = __atomic_load_n(&lazyInitializer, __ATOMIC_ACQUIRE);
#elif _MSC_VER
const Initializer* i = *static_cast<Initializer const* const volatile*>(&lazyInitializer);
std::atomic_thread_fence(std::memory_order_acquire);
#else
#error "Platform not supported"
#endif
if (i != nullptr) i->init(this);
}
inline bool isUnbound() const;
// Checks if this schema is the result of calling SchemaLoader::getUnbound(), in which case
// binding lookups need to be handled specially.
};
struct RawSchema {
// The generated code defines a constant RawSchema for every compiled declaration.
//
// This is an internal structure which could change in the future.
uint64_t id;
const word* encodedNode;
// Encoded SchemaNode, readable via readMessageUnchecked<schema::Node>(encodedNode).
uint32_t encodedSize;
// Size of encodedNode, in words.
const RawSchema* const* dependencies;
// Pointers to other types on which this one depends, sorted by ID. The schemas in this table
// may be uninitialized -- you must call ensureInitialized() on the one you wish to use before
// using it.
//
// TODO(someday): Make this a hashtable.
const uint16_t* membersByName;
// Indexes of members sorted by name. Used to implement name lookup.
// TODO(someday): Make this a hashtable.
uint32_t dependencyCount;
uint32_t memberCount;
// Sizes of above tables.
const uint16_t* membersByDiscriminant;
// List of all member indexes ordered by discriminant value. Those which don't have a
// discriminant value are listed at the end, in order by ordinal.
const RawSchema* canCastTo;
// Points to the RawSchema of a compiled-in type to which it is safe to cast any DynamicValue
// with this schema. This is null for all compiled-in types; it is only set by SchemaLoader on
// dynamically-loaded types.
class Initializer {
public:
virtual void init(const RawSchema* schema) const = 0;
};
const Initializer* lazyInitializer;
// Lazy initializer, invoked by ensureInitialized().
inline void ensureInitialized() const {
// Lazy initialization support. Invoke to ensure that initialization has taken place. This
// is required in particular when traversing the dependency list. RawSchemas for compiled-in
// types are always initialized; only dynamically-loaded schemas may be lazy.
#if __GNUC__
const Initializer* i = __atomic_load_n(&lazyInitializer, __ATOMIC_ACQUIRE);
#elif _MSC_VER
const Initializer* i = *static_cast<Initializer const* const volatile*>(&lazyInitializer);
std::atomic_thread_fence(std::memory_order_acquire);
#else
#error "Platform not supported"
#endif
if (i != nullptr) i->init(this);
}
RawBrandedSchema defaultBrand;
// Specifies the brand to use for this schema if no generic parameters have been bound to
// anything. Generally, in the default brand, all generic parameters are treated as if they were
// bound to `AnyPointer`.
};
inline bool RawBrandedSchema::isUnbound() const {
// The unbound schema is the only one that has no scopes but is not the default schema.
return scopeCount == 0 && this != &generic->defaultBrand;
}
} // namespace _ (private)
} // namespace capnp
#endif // CAPNP_RAW_SCHEMA_H_