cannam@148: // Copyright (c) 2013-2016 Sandstorm Development Group, Inc. and contributors cannam@148: // Licensed under the MIT License: cannam@148: // cannam@148: // Permission is hereby granted, free of charge, to any person obtaining a copy cannam@148: // of this software and associated documentation files (the "Software"), to deal cannam@148: // in the Software without restriction, including without limitation the rights cannam@148: // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell cannam@148: // copies of the Software, and to permit persons to whom the Software is cannam@148: // furnished to do so, subject to the following conditions: cannam@148: // cannam@148: // The above copyright notice and this permission notice shall be included in cannam@148: // all copies or substantial portions of the Software. cannam@148: // cannam@148: // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR cannam@148: // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, cannam@148: // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE cannam@148: // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER cannam@148: // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, cannam@148: // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN cannam@148: // THE SOFTWARE. cannam@148: cannam@148: #include cannam@148: #include cannam@148: #include cannam@148: #include cannam@148: #include "common.h" cannam@148: #include "layout.h" cannam@148: #include "any.h" cannam@148: cannam@148: #ifndef CAPNP_MESSAGE_H_ cannam@148: #define CAPNP_MESSAGE_H_ cannam@148: cannam@148: #if defined(__GNUC__) && !defined(CAPNP_HEADER_WARNINGS) cannam@148: #pragma GCC system_header cannam@148: #endif cannam@148: cannam@148: namespace capnp { cannam@148: cannam@148: namespace _ { // private cannam@148: class ReaderArena; cannam@148: class BuilderArena; cannam@148: } cannam@148: cannam@148: class StructSchema; cannam@148: class Orphanage; cannam@148: template cannam@148: class Orphan; cannam@148: cannam@148: // ======================================================================================= cannam@148: cannam@148: struct ReaderOptions { cannam@148: // Options controlling how data is read. cannam@148: cannam@148: uint64_t traversalLimitInWords = 8 * 1024 * 1024; cannam@148: // Limits how many total words of data are allowed to be traversed. Traversal is counted when cannam@148: // a new struct or list builder is obtained, e.g. from a get() accessor. This means that calling cannam@148: // the getter for the same sub-struct multiple times will cause it to be double-counted. Once cannam@148: // the traversal limit is reached, an error will be reported. cannam@148: // cannam@148: // This limit exists for security reasons. It is possible for an attacker to construct a message cannam@148: // in which multiple pointers point at the same location. This is technically invalid, but hard cannam@148: // to detect. Using such a message, an attacker could cause a message which is small on the wire cannam@148: // to appear much larger when actually traversed, possibly exhausting server resources leading to cannam@148: // denial-of-service. cannam@148: // cannam@148: // It makes sense to set a traversal limit that is much larger than the underlying message. cannam@148: // Together with sensible coding practices (e.g. trying to avoid calling sub-object getters cannam@148: // multiple times, which is expensive anyway), this should provide adequate protection without cannam@148: // inconvenience. cannam@148: // cannam@148: // The default limit is 64 MiB. This may or may not be a sensible number for any given use case, cannam@148: // but probably at least prevents easy exploitation while also avoiding causing problems in most cannam@148: // typical cases. cannam@148: cannam@148: int nestingLimit = 64; cannam@148: // Limits how deeply-nested a message structure can be, e.g. structs containing other structs or cannam@148: // lists of structs. cannam@148: // cannam@148: // Like the traversal limit, this limit exists for security reasons. Since it is common to use cannam@148: // recursive code to traverse recursive data structures, an attacker could easily cause a stack cannam@148: // overflow by sending a very-deeply-nested (or even cyclic) message, without the message even cannam@148: // being very large. The default limit of 64 is probably low enough to prevent any chance of cannam@148: // stack overflow, yet high enough that it is never a problem in practice. cannam@148: }; cannam@148: cannam@148: class MessageReader { cannam@148: // Abstract interface for an object used to read a Cap'n Proto message. Subclasses of cannam@148: // MessageReader are responsible for reading the raw, flat message content. Callers should cannam@148: // usually call `messageReader.getRoot()` to get a `MyStructType::Reader` cannam@148: // representing the root of the message, then use that to traverse the message content. cannam@148: // cannam@148: // Some common subclasses of `MessageReader` include `SegmentArrayMessageReader`, whose cannam@148: // constructor accepts pointers to the raw data, and `StreamFdMessageReader` (from cannam@148: // `serialize.h`), which reads the message from a file descriptor. One might implement other cannam@148: // subclasses to handle things like reading from shared memory segments, mmap()ed files, etc. cannam@148: cannam@148: public: cannam@148: MessageReader(ReaderOptions options); cannam@148: // It is suggested that subclasses take ReaderOptions as a constructor parameter, but give it a cannam@148: // default value of "ReaderOptions()". The base class constructor doesn't have a default value cannam@148: // in order to remind subclasses that they really need to give the user a way to provide this. cannam@148: cannam@148: virtual ~MessageReader() noexcept(false); cannam@148: cannam@148: virtual kj::ArrayPtr getSegment(uint id) = 0; cannam@148: // Gets the segment with the given ID, or returns null if no such segment exists. This method cannam@148: // will be called at most once for each segment ID. cannam@148: cannam@148: inline const ReaderOptions& getOptions(); cannam@148: // Get the options passed to the constructor. cannam@148: cannam@148: template cannam@148: typename RootType::Reader getRoot(); cannam@148: // Get the root struct of the message, interpreting it as the given struct type. cannam@148: cannam@148: template cannam@148: typename RootType::Reader getRoot(SchemaType schema); cannam@148: // Dynamically interpret the root struct of the message using the given schema (a StructSchema). cannam@148: // RootType in this case must be DynamicStruct, and you must #include to cannam@148: // use this. cannam@148: cannam@148: bool isCanonical(); cannam@148: // Returns whether the message encoded in the reader is in canonical form. cannam@148: cannam@148: private: cannam@148: ReaderOptions options; cannam@148: cannam@148: // Space in which we can construct a ReaderArena. We don't use ReaderArena directly here cannam@148: // because we don't want clients to have to #include arena.h, which itself includes a bunch of cannam@148: // big STL headers. We don't use a pointer to a ReaderArena because that would require an cannam@148: // extra malloc on every message which could be expensive when processing small messages. cannam@148: void* arenaSpace[15 + sizeof(kj::MutexGuarded) / sizeof(void*)]; cannam@148: bool allocatedArena; cannam@148: cannam@148: _::ReaderArena* arena() { return reinterpret_cast<_::ReaderArena*>(arenaSpace); } cannam@148: AnyPointer::Reader getRootInternal(); cannam@148: }; cannam@148: cannam@148: class MessageBuilder { cannam@148: // Abstract interface for an object used to allocate and build a message. Subclasses of cannam@148: // MessageBuilder are responsible for allocating the space in which the message will be written. cannam@148: // The most common subclass is `MallocMessageBuilder`, but other subclasses may be used to do cannam@148: // tricky things like allocate messages in shared memory or mmap()ed files. cannam@148: // cannam@148: // Creating a new message ususually means allocating a new MessageBuilder (ideally on the stack) cannam@148: // and then calling `messageBuilder.initRoot()` to get a `MyStructType::Builder`. cannam@148: // That, in turn, can be used to fill in the message content. When done, you can call cannam@148: // `messageBuilder.getSegmentsForOutput()` to get a list of flat data arrays containing the cannam@148: // message. cannam@148: cannam@148: public: cannam@148: MessageBuilder(); cannam@148: virtual ~MessageBuilder() noexcept(false); cannam@148: KJ_DISALLOW_COPY(MessageBuilder); cannam@148: cannam@148: struct SegmentInit { cannam@148: kj::ArrayPtr space; cannam@148: cannam@148: size_t wordsUsed; cannam@148: // Number of words in `space` which are used; the rest are free space in which additional cannam@148: // objects may be allocated. cannam@148: }; cannam@148: cannam@148: explicit MessageBuilder(kj::ArrayPtr segments); cannam@148: // Create a MessageBuilder backed by existing memory. This is an advanced interface that most cannam@148: // people should not use. THIS METHOD IS INSECURE; see below. cannam@148: // cannam@148: // This allows a MessageBuilder to be constructed to modify an in-memory message without first cannam@148: // making a copy of the content. This is especially useful in conjunction with mmap(). cannam@148: // cannam@148: // The contents of each segment must outlive the MessageBuilder, but the SegmentInit array itself cannam@148: // only need outlive the constructor. cannam@148: // cannam@148: // SECURITY: Do not use this in conjunction with untrusted data. This constructor assumes that cannam@148: // the input message is valid. This constructor is designed to be used with data you control, cannam@148: // e.g. an mmap'd file which is owned and accessed by only one program. When reading data you cannam@148: // do not trust, you *must* load it into a Reader and then copy into a Builder as a means of cannam@148: // validating the content. cannam@148: // cannam@148: // WARNING: It is NOT safe to initialize a MessageBuilder in this way from memory that is cannam@148: // currently in use by another MessageBuilder or MessageReader. Other readers/builders will cannam@148: // not observe changes to the segment sizes nor newly-allocated segments caused by allocating cannam@148: // new objects in this message. cannam@148: cannam@148: virtual kj::ArrayPtr allocateSegment(uint minimumSize) = 0; cannam@148: // Allocates an array of at least the given number of words, throwing an exception or crashing if cannam@148: // this is not possible. It is expected that this method will usually return more space than cannam@148: // requested, and the caller should use that extra space as much as possible before allocating cannam@148: // more. The returned space remains valid at least until the MessageBuilder is destroyed. cannam@148: // cannam@148: // Cap'n Proto will only call this once at a time, so the subclass need not worry about cannam@148: // thread-safety. cannam@148: cannam@148: template cannam@148: typename RootType::Builder initRoot(); cannam@148: // Initialize the root struct of the message as the given struct type. cannam@148: cannam@148: template cannam@148: void setRoot(Reader&& value); cannam@148: // Set the root struct to a deep copy of the given struct. cannam@148: cannam@148: template cannam@148: typename RootType::Builder getRoot(); cannam@148: // Get the root struct of the message, interpreting it as the given struct type. cannam@148: cannam@148: template cannam@148: typename RootType::Builder getRoot(SchemaType schema); cannam@148: // Dynamically interpret the root struct of the message using the given schema (a StructSchema). cannam@148: // RootType in this case must be DynamicStruct, and you must #include to cannam@148: // use this. cannam@148: cannam@148: template cannam@148: typename RootType::Builder initRoot(SchemaType schema); cannam@148: // Dynamically init the root struct of the message using the given schema (a StructSchema). cannam@148: // RootType in this case must be DynamicStruct, and you must #include to cannam@148: // use this. cannam@148: cannam@148: template cannam@148: void adoptRoot(Orphan&& orphan); cannam@148: // Like setRoot() but adopts the orphan without copying. cannam@148: cannam@148: kj::ArrayPtr> getSegmentsForOutput(); cannam@148: // Get the raw data that makes up the message. cannam@148: cannam@148: Orphanage getOrphanage(); cannam@148: cannam@148: bool isCanonical(); cannam@148: // Check whether the message builder is in canonical form cannam@148: cannam@148: private: cannam@148: void* arenaSpace[22]; cannam@148: // Space in which we can construct a BuilderArena. We don't use BuilderArena directly here cannam@148: // because we don't want clients to have to #include arena.h, which itself includes a bunch of cannam@148: // big STL headers. We don't use a pointer to a BuilderArena because that would require an cannam@148: // extra malloc on every message which could be expensive when processing small messages. cannam@148: cannam@148: bool allocatedArena = false; cannam@148: // We have to initialize the arena lazily because when we do so we want to allocate the root cannam@148: // pointer immediately, and this will allocate a segment, which requires a virtual function cannam@148: // call on the MessageBuilder. We can't do such a call in the constructor since the subclass cannam@148: // isn't constructed yet. This is kind of annoying because it means that getOrphanage() is cannam@148: // not thread-safe, but that shouldn't be a huge deal... cannam@148: cannam@148: _::BuilderArena* arena() { return reinterpret_cast<_::BuilderArena*>(arenaSpace); } cannam@148: _::SegmentBuilder* getRootSegment(); cannam@148: AnyPointer::Builder getRootInternal(); cannam@148: }; cannam@148: cannam@148: template cannam@148: typename RootType::Reader readMessageUnchecked(const word* data); cannam@148: // IF THE INPUT IS INVALID, THIS MAY CRASH, CORRUPT MEMORY, CREATE A SECURITY HOLE IN YOUR APP, cannam@148: // MURDER YOUR FIRST-BORN CHILD, AND/OR BRING ABOUT ETERNAL DAMNATION ON ALL OF HUMANITY. DO NOT cannam@148: // USE UNLESS YOU UNDERSTAND THE CONSEQUENCES. cannam@148: // cannam@148: // Given a pointer to a known-valid message located in a single contiguous memory segment, cannam@148: // returns a reader for that message. No bounds-checking will be done while traversing this cannam@148: // message. Use this only if you have already verified that all pointers are valid and in-bounds, cannam@148: // and there are no far pointers in the message. cannam@148: // cannam@148: // To create a message that can be passed to this function, build a message using a MallocAllocator cannam@148: // whose preferred segment size is larger than the message size. This guarantees that the message cannam@148: // will be allocated as a single segment, meaning getSegmentsForOutput() returns a single word cannam@148: // array. That word array is your message; you may pass a pointer to its first word into cannam@148: // readMessageUnchecked() to read the message. cannam@148: // cannam@148: // This can be particularly handy for embedding messages in generated code: you can cannam@148: // embed the raw bytes (using AlignedData) then make a Reader for it using this. This is the way cannam@148: // default values are embedded in code generated by the Cap'n Proto compiler. E.g., if you have cannam@148: // a message MyMessage, you can read its default value like so: cannam@148: // MyMessage::Reader reader = Message::readMessageUnchecked(MyMessage::DEFAULT.words); cannam@148: // cannam@148: // To sanitize a message from an untrusted source such that it can be safely passed to cannam@148: // readMessageUnchecked(), use copyToUnchecked(). cannam@148: cannam@148: template cannam@148: void copyToUnchecked(Reader&& reader, kj::ArrayPtr uncheckedBuffer); cannam@148: // Copy the content of the given reader into the given buffer, such that it can safely be passed to cannam@148: // readMessageUnchecked(). The buffer's size must be exactly reader.totalSizeInWords() + 1, cannam@148: // otherwise an exception will be thrown. The buffer must be zero'd before calling. cannam@148: cannam@148: template cannam@148: typename RootType::Reader readDataStruct(kj::ArrayPtr data); cannam@148: // Interprets the given data as a single, data-only struct. Only primitive fields (booleans, cannam@148: // numbers, and enums) will be readable; all pointers will be null. This is useful if you want cannam@148: // to use Cap'n Proto as a language/platform-neutral way to pack some bits. cannam@148: // cannam@148: // The input is a word array rather than a byte array to enforce alignment. If you have a byte cannam@148: // array which you know is word-aligned (or if your platform supports unaligned reads and you don't cannam@148: // mind the performance penalty), then you can use `reinterpret_cast` to convert a byte array into cannam@148: // a word array: cannam@148: // cannam@148: // kj::arrayPtr(reinterpret_cast(bytes.begin()), cannam@148: // reinterpret_cast(bytes.end())) cannam@148: cannam@148: template cannam@148: typename kj::ArrayPtr writeDataStruct(BuilderType builder); cannam@148: // Given a struct builder, get the underlying data section as a word array, suitable for passing cannam@148: // to `readDataStruct()`. cannam@148: // cannam@148: // Note that you may call `.toBytes()` on the returned value to convert to `ArrayPtr`. cannam@148: cannam@148: template cannam@148: static typename Type::Reader defaultValue(); cannam@148: // Get a default instance of the given struct or list type. cannam@148: // cannam@148: // TODO(cleanup): Find a better home for this function? cannam@148: cannam@148: // ======================================================================================= cannam@148: cannam@148: class SegmentArrayMessageReader: public MessageReader { cannam@148: // A simple MessageReader that reads from an array of word arrays representing all segments. cannam@148: // In particular you can read directly from the output of MessageBuilder::getSegmentsForOutput() cannam@148: // (although it would probably make more sense to call builder.getRoot().asReader() in that case). cannam@148: cannam@148: public: cannam@148: SegmentArrayMessageReader(kj::ArrayPtr> segments, cannam@148: ReaderOptions options = ReaderOptions()); cannam@148: // Creates a message pointing at the given segment array, without taking ownership of the cannam@148: // segments. All arrays passed in must remain valid until the MessageReader is destroyed. cannam@148: cannam@148: KJ_DISALLOW_COPY(SegmentArrayMessageReader); cannam@148: ~SegmentArrayMessageReader() noexcept(false); cannam@148: cannam@148: virtual kj::ArrayPtr getSegment(uint id) override; cannam@148: cannam@148: private: cannam@148: kj::ArrayPtr> segments; cannam@148: }; cannam@148: cannam@148: enum class AllocationStrategy: uint8_t { cannam@148: FIXED_SIZE, cannam@148: // The builder will prefer to allocate the same amount of space for each segment with no cannam@148: // heuristic growth. It will still allocate larger segments when the preferred size is too small cannam@148: // for some single object. This mode is generally not recommended, but can be particularly useful cannam@148: // for testing in order to force a message to allocate a predictable number of segments. Note cannam@148: // that you can force every single object in the message to be located in a separate segment by cannam@148: // using this mode with firstSegmentWords = 0. cannam@148: cannam@148: GROW_HEURISTICALLY cannam@148: // The builder will heuristically decide how much space to allocate for each segment. Each cannam@148: // allocated segment will be progressively larger than the previous segments on the assumption cannam@148: // that message sizes are exponentially distributed. The total number of segments that will be cannam@148: // allocated for a message of size n is O(log n). cannam@148: }; cannam@148: cannam@148: constexpr uint SUGGESTED_FIRST_SEGMENT_WORDS = 1024; cannam@148: constexpr AllocationStrategy SUGGESTED_ALLOCATION_STRATEGY = AllocationStrategy::GROW_HEURISTICALLY; cannam@148: cannam@148: class MallocMessageBuilder: public MessageBuilder { cannam@148: // A simple MessageBuilder that uses malloc() (actually, calloc()) to allocate segments. This cannam@148: // implementation should be reasonable for any case that doesn't require writing the message to cannam@148: // a specific location in memory. cannam@148: cannam@148: public: cannam@148: explicit MallocMessageBuilder(uint firstSegmentWords = SUGGESTED_FIRST_SEGMENT_WORDS, cannam@148: AllocationStrategy allocationStrategy = SUGGESTED_ALLOCATION_STRATEGY); cannam@148: // Creates a BuilderContext which allocates at least the given number of words for the first cannam@148: // segment, and then uses the given strategy to decide how much to allocate for subsequent cannam@148: // segments. When choosing a value for firstSegmentWords, consider that: cannam@148: // 1) Reading and writing messages gets slower when multiple segments are involved, so it's good cannam@148: // if most messages fit in a single segment. cannam@148: // 2) Unused bytes will not be written to the wire, so generally it is not a big deal to allocate cannam@148: // more space than you need. It only becomes problematic if you are allocating many messages cannam@148: // in parallel and thus use lots of memory, or if you allocate so much extra space that just cannam@148: // zeroing it out becomes a bottleneck. cannam@148: // The defaults have been chosen to be reasonable for most people, so don't change them unless you cannam@148: // have reason to believe you need to. cannam@148: cannam@148: explicit MallocMessageBuilder(kj::ArrayPtr firstSegment, cannam@148: AllocationStrategy allocationStrategy = SUGGESTED_ALLOCATION_STRATEGY); cannam@148: // This version always returns the given array for the first segment, and then proceeds with the cannam@148: // allocation strategy. This is useful for optimization when building lots of small messages in cannam@148: // a tight loop: you can reuse the space for the first segment. cannam@148: // cannam@148: // firstSegment MUST be zero-initialized. MallocMessageBuilder's destructor will write new zeros cannam@148: // over any space that was used so that it can be reused. cannam@148: cannam@148: KJ_DISALLOW_COPY(MallocMessageBuilder); cannam@148: virtual ~MallocMessageBuilder() noexcept(false); cannam@148: cannam@148: virtual kj::ArrayPtr allocateSegment(uint minimumSize) override; cannam@148: cannam@148: private: cannam@148: uint nextSize; cannam@148: AllocationStrategy allocationStrategy; cannam@148: cannam@148: bool ownFirstSegment; cannam@148: bool returnedFirstSegment; cannam@148: cannam@148: void* firstSegment; cannam@148: cannam@148: struct MoreSegments; cannam@148: kj::Maybe> moreSegments; cannam@148: }; cannam@148: cannam@148: class FlatMessageBuilder: public MessageBuilder { cannam@148: // THIS IS NOT THE CLASS YOU'RE LOOKING FOR. cannam@148: // cannam@148: // If you want to write a message into already-existing scratch space, use `MallocMessageBuilder` cannam@148: // and pass the scratch space to its constructor. It will then only fall back to malloc() if cannam@148: // the scratch space is not large enough. cannam@148: // cannam@148: // Do NOT use this class unless you really know what you're doing. This class is problematic cannam@148: // because it requires advance knowledge of the size of your message, which is usually impossible cannam@148: // to determine without actually building the message. The class was created primarily to cannam@148: // implement `copyToUnchecked()`, which itself exists only to support other internal parts of cannam@148: // the Cap'n Proto implementation. cannam@148: cannam@148: public: cannam@148: explicit FlatMessageBuilder(kj::ArrayPtr array); cannam@148: KJ_DISALLOW_COPY(FlatMessageBuilder); cannam@148: virtual ~FlatMessageBuilder() noexcept(false); cannam@148: cannam@148: void requireFilled(); cannam@148: // Throws an exception if the flat array is not exactly full. cannam@148: cannam@148: virtual kj::ArrayPtr allocateSegment(uint minimumSize) override; cannam@148: cannam@148: private: cannam@148: kj::ArrayPtr array; cannam@148: bool allocated; cannam@148: }; cannam@148: cannam@148: // ======================================================================================= cannam@148: // implementation details cannam@148: cannam@148: inline const ReaderOptions& MessageReader::getOptions() { cannam@148: return options; cannam@148: } cannam@148: cannam@148: template cannam@148: inline typename RootType::Reader MessageReader::getRoot() { cannam@148: return getRootInternal().getAs(); cannam@148: } cannam@148: cannam@148: template cannam@148: inline typename RootType::Builder MessageBuilder::initRoot() { cannam@148: return getRootInternal().initAs(); cannam@148: } cannam@148: cannam@148: template cannam@148: inline void MessageBuilder::setRoot(Reader&& value) { cannam@148: getRootInternal().setAs>(value); cannam@148: } cannam@148: cannam@148: template cannam@148: inline typename RootType::Builder MessageBuilder::getRoot() { cannam@148: return getRootInternal().getAs(); cannam@148: } cannam@148: cannam@148: template cannam@148: void MessageBuilder::adoptRoot(Orphan&& orphan) { cannam@148: return getRootInternal().adopt(kj::mv(orphan)); cannam@148: } cannam@148: cannam@148: template cannam@148: typename RootType::Reader MessageReader::getRoot(SchemaType schema) { cannam@148: return getRootInternal().getAs(schema); cannam@148: } cannam@148: cannam@148: template cannam@148: typename RootType::Builder MessageBuilder::getRoot(SchemaType schema) { cannam@148: return getRootInternal().getAs(schema); cannam@148: } cannam@148: cannam@148: template cannam@148: typename RootType::Builder MessageBuilder::initRoot(SchemaType schema) { cannam@148: return getRootInternal().initAs(schema); cannam@148: } cannam@148: cannam@148: template cannam@148: typename RootType::Reader readMessageUnchecked(const word* data) { cannam@148: return AnyPointer::Reader(_::PointerReader::getRootUnchecked(data)).getAs(); cannam@148: } cannam@148: cannam@148: template cannam@148: void copyToUnchecked(Reader&& reader, kj::ArrayPtr uncheckedBuffer) { cannam@148: FlatMessageBuilder builder(uncheckedBuffer); cannam@148: builder.setRoot(kj::fwd(reader)); cannam@148: builder.requireFilled(); cannam@148: } cannam@148: cannam@148: template cannam@148: typename RootType::Reader readDataStruct(kj::ArrayPtr data) { cannam@148: return typename RootType::Reader(_::StructReader(data)); cannam@148: } cannam@148: cannam@148: template cannam@148: typename kj::ArrayPtr writeDataStruct(BuilderType builder) { cannam@148: auto bytes = _::PointerHelpers>::getInternalBuilder(kj::mv(builder)) cannam@148: .getDataSectionAsBlob(); cannam@148: return kj::arrayPtr(reinterpret_cast(bytes.begin()), cannam@148: reinterpret_cast(bytes.end())); cannam@148: } cannam@148: cannam@148: template cannam@148: static typename Type::Reader defaultValue() { cannam@148: return typename Type::Reader(_::StructReader()); cannam@148: } cannam@148: cannam@148: template cannam@148: kj::Array canonicalize(T&& reader) { cannam@148: return _::PointerHelpers>::getInternalReader(reader).canonicalize(); cannam@148: } cannam@148: cannam@148: } // namespace capnp cannam@148: cannam@148: #endif // CAPNP_MESSAGE_H_