+++ /dev/null
-// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
-// vim: ts=8 sw=2 smarttab
-
-#ifndef CEPH_RGW_CLIENT_IO_H
-#define CEPH_RGW_CLIENT_IO_H
-
-#include <exception>
-#include <string>
-#include <streambuf>
-#include <istream>
-#include <stdlib.h>
-#include <system_error>
-
-#include <boost/utility/string_ref.hpp>
-
-#include "include/types.h"
-#include "rgw_common.h"
-
-
-class RGWRestfulIO;
-
-namespace rgw {
-namespace io {
-
-using Exception = std::system_error;
-
-/* The minimal and simplest subset of methods that a client of RadosGW can be
- * interacted with. */
-class BasicClient {
-protected:
- virtual void init_env(CephContext *cct) = 0;
-
-public:
- virtual ~BasicClient() = default;
-
- /* Initialize the BasicClient and inject CephContext. */
- void init(CephContext *cct);
-
- /* Return the RGWEnv describing the environment that a given request lives in.
- * The method does not throw exceptions. */
- virtual RGWEnv& get_env() noexcept = 0;
-
- /* Complete request.
- * On success returns number of bytes generated for a direct client of RadosGW.
- * On failure throws rgw::io::Exception containing errno. */
- virtual size_t complete_request() = 0;
-}; /* rgw::io::Client */
-
-
-class Accounter {
-public:
- virtual ~Accounter() = default;
-
- /* Enable or disable the accounting of both sent and received data. Changing
- * the state does not affect the counters. */
- virtual void set_account(bool enabled) = 0;
-
- /* Return number of bytes sent to a direct client of RadosGW (direct means
- * eg. a web server instance in the case of using FastCGI front-end) when
- * the accounting was enabled. */
- virtual uint64_t get_bytes_sent() const = 0;
-
- /* Return number of bytes received from a direct client of RadosGW (direct
- * means eg. a web server instance in the case of using FastCGI front-end)
- * when the accounting was enabled. */
- virtual uint64_t get_bytes_received() const = 0;
-}; /* rgw::io::Accounter */
-
-
-/* Interface abstracting restful interactions with clients, usually through
- * the HTTP protocol. The methods participating in the response generation
- * process should be called in the specific order:
- * 1. send_100_continue() - at most once,
- * 2. send_status() - exactly once,
- * 3. Any of:
- * a. send_header(),
- * b. send_content_length() XOR send_chunked_transfer_encoding()
- * Please note that only one of those two methods must be called
- at most once.
- * 4. complete_header() - exactly once,
- * 5. send_body()
- * 6. complete_request() - exactly once.
- * There are no restrictions on flush() - it may be called in any moment.
- *
- * Receiving data from a client isn't a subject to any further call order
- * restrictions besides those imposed by BasicClient. That is, get_env()
- * and recv_body can be mixed. */
-class RestfulClient : public BasicClient {
- template<typename T> friend class DecoratedRestfulClient;
-
-public:
- /* Generate the 100 Continue message.
- * On success returns number of bytes generated for a direct client of RadosGW.
- * On failure throws rgw::io::Exception containing errno. */
- virtual size_t send_100_continue() = 0;
-
- /* Generate the response's status part taking the HTTP status code as @status
- * and its name pointed in @status_name.
- * On success returns number of bytes generated for a direct client of RadosGW.
- * On failure throws rgw::io::Exception containing errno. */
- virtual size_t send_status(int status, const char *status_name) = 0;
-
- /* Generate header. On success returns number of bytes generated for a direct
- * client of RadosGW. On failure throws rgw::io::Exception containing errno.
- *
- * boost::string_ref is being used because of length it internally carries. */
- virtual size_t send_header(const boost::string_ref& name,
- const boost::string_ref& value) = 0;
-
- /* Inform a client about a content length. Takes number of bytes as @len.
- * On success returns number of bytes generated for a direct client of RadosGW.
- * On failure throws rgw::io::Exception containing errno.
- *
- * CALL LIMITATIONS:
- * - The method must be called EXACTLY ONCE.
- * - The method is interchangeable with send_chunked_transfer_encoding(). */
- virtual size_t send_content_length(uint64_t len) = 0;
-
- /* Inform a client that the chunked transfer encoding will be used.
- * On success returns number of bytes generated for a direct client of RadosGW.
- * On failure throws rgw::io::Exception containing errno.
- *
- * CALL LIMITATIONS:
- * - The method must be called EXACTLY ONCE.
- * - The method is interchangeable with send_content_length(). */
- virtual size_t send_chunked_transfer_encoding() {
- /* This is a null implementation. We don't send anything here, even the HTTP
- * header. The intended behaviour should be provided through a decorator or
- * directly by a given front-end. */
- return 0;
- }
-
- /* Generate completion (the CRLF sequence separating headers and body in
- * the case of HTTP) of headers. On success returns number of generated bytes
- * for a direct client of RadosGW. On failure throws rgw::io::Exception with
- * errno. */
- virtual size_t complete_header() = 0;
-
- /* Receive no more than @max bytes from a request's body and store it in
- * buffer pointed by @buf. On success returns number of bytes received from
- * a direct client of RadosGW that has been stored in @buf. On failure throws
- * rgw::io::Exception containing errno. */
- virtual size_t recv_body(char* buf, size_t max) = 0;
-
- /* Generate a part of response's body by taking exactly @len bytes from
- * the buffer pointed by @buf. On success returns number of generated bytes
- * of response's body. On failure throws rgw::io::Exception. */
- virtual size_t send_body(const char* buf, size_t len) = 0;
-
- /* Flushes all already generated data to a direct client of RadosGW.
- * On failure throws rgw::io::Exception containing errno. */
- virtual void flush() = 0;
-} /* rgw::io::RestfulClient */;
-
-
-/* Abstract decorator over any implementation of rgw::io::RestfulClient
- * which could be provided both as a pointer-to-object or the object itself. */
-template <typename DecorateeT>
-class DecoratedRestfulClient : public RestfulClient {
- template<typename T> friend class DecoratedRestfulClient;
- friend RGWRestfulIO;
-
- typedef typename std::remove_pointer<DecorateeT>::type DerefedDecorateeT;
-
- static_assert(std::is_base_of<RestfulClient, DerefedDecorateeT>::value,
- "DecorateeT must be a subclass of rgw::io::RestfulClient");
-
- DecorateeT decoratee;
-
- /* There is an indirection layer over accessing decoratee to share the same
- * code base between dynamic and static decorators. The difference is about
- * what we store internally: pointer to a decorated object versus the whole
- * object itself. */
- template <typename T = void,
- typename std::enable_if<
- ! std::is_pointer<DecorateeT>::value, T>::type* = nullptr>
- DerefedDecorateeT& get_decoratee() {
- return decoratee;
- }
-
-protected:
- template <typename T = void,
- typename std::enable_if<
- std::is_pointer<DecorateeT>::value, T>::type* = nullptr>
- DerefedDecorateeT& get_decoratee() {
- return *decoratee;
- }
-
- /* Dynamic decorators (those storing a pointer instead of the decorated
- * object itself) can be reconfigured on-the-fly. HOWEVER: there are no
- * facilities for orchestrating such changes. Callers must take care of
- * atomicity and thread-safety. */
- template <typename T = void,
- typename std::enable_if<
- std::is_pointer<DecorateeT>::value, T>::type* = nullptr>
- void set_decoratee(DerefedDecorateeT& new_dec) {
- decoratee = &new_dec;
- }
-
- void init_env(CephContext *cct) override {
- return get_decoratee().init_env(cct);
- }
-
-public:
- DecoratedRestfulClient(DecorateeT&& decoratee)
- : decoratee(std::forward<DecorateeT>(decoratee)) {
- }
-
- size_t send_status(const int status,
- const char* const status_name) override {
- return get_decoratee().send_status(status, status_name);
- }
-
- size_t send_100_continue() override {
- return get_decoratee().send_100_continue();
- }
-
- size_t send_header(const boost::string_ref& name,
- const boost::string_ref& value) override {
- return get_decoratee().send_header(name, value);
- }
-
- size_t send_content_length(const uint64_t len) override {
- return get_decoratee().send_content_length(len);
- }
-
- size_t send_chunked_transfer_encoding() override {
- return get_decoratee().send_chunked_transfer_encoding();
- }
-
- size_t complete_header() override {
- return get_decoratee().complete_header();
- }
-
- size_t recv_body(char* const buf, const size_t max) override {
- return get_decoratee().recv_body(buf, max);
- }
-
- size_t send_body(const char* const buf,
- const size_t len) override {
- return get_decoratee().send_body(buf, len);
- }
-
- void flush() override {
- return get_decoratee().flush();
- }
-
- RGWEnv& get_env() noexcept override {
- return get_decoratee().get_env();
- }
-
- size_t complete_request() override {
- return get_decoratee().complete_request();
- }
-} /* rgw::io::DecoratedRestfulClient */;
-
-
-/* Interface that should be provided by a front-end class wanting to to use
- * the low-level buffering offered by i.e. StaticOutputBufferer. */
-class BuffererSink {
-public:
- virtual ~BuffererSink() = default;
-
- /* Send exactly @len bytes from the memory location pointed by @buf.
- * On success returns @len. On failure throws rgw::io::Exception. */
- virtual size_t write_data(const char *buf, size_t len) = 0;
-};
-
-/* Utility class providing RestfulClient's implementations with facilities
- * for low-level buffering without relying on dynamic memory allocations.
- * The buffer is carried entirely on stack. This narrows down applicability
- * to these situations where buffers are relatively small. This perfectly
- * fits the needs of composing an HTTP header. Without that a front-end
- * might need to issue a lot of small IO operations leading to increased
- * overhead on syscalls and fragmentation of a message if the Nagle's
- * algorithm won't be able to form a single TCP segment (usually when
- * running on extremely fast network interfaces like the loopback). */
-template <size_t BufferSizeV = 4096>
-class StaticOutputBufferer : public std::streambuf {
- static_assert(BufferSizeV >= sizeof(std::streambuf::char_type),
- "Buffer size must be bigger than a single char_type.");
-
- using std::streambuf::int_type;
-
- int_type overflow(const int_type c) override {
- *pptr() = c;
- pbump(sizeof(std::streambuf::char_type));
-
- if (! sync()) {
- /* No error, the buffer has been successfully synchronized. */
- return c;
- } else {
- return std::streambuf::traits_type::eof();
- }
- }
-
- int sync() override {
- const auto len = static_cast<size_t>(std::streambuf::pptr() -
- std::streambuf::pbase());
- std::streambuf::pbump(-len);
- sink.write_data(std::streambuf::pbase(), len);
- /* Always return success here. In case of failure write_data() will throw
- * rgw::io::Exception. */
- return 0;
- }
-
- BuffererSink& sink;
- std::streambuf::char_type buffer[BufferSizeV];
-
-public:
- StaticOutputBufferer(BuffererSink& sink)
- : sink(sink) {
- constexpr size_t len = sizeof(buffer) - sizeof(std::streambuf::char_type);
- std::streambuf::setp(buffer, buffer + len);
- }
-};
-
-} /* namespace rgw */
-} /* namespace io */
-
-
-/* We're doing this nasty thing only because of extensive usage of templates
- * to implement the static decorator pattern. C++ templates de facto enforce
- * mixing interfaces with implementation. Additionally, those classes derive
- * from RGWRestfulIO defined here. I believe that including in the middle of
- * file is still better than polluting it directly. */
-#include "rgw_client_io_filters.h"
-
-
-/* RGWRestfulIO: high level interface to interact with RESTful clients. What
- * differentiates it from rgw::io::RestfulClient is providing more specific APIs
- * like rgw::io::Accounter or the AWS Auth v4 stuff implemented by filters
- * while hiding the pipelined architecture from clients.
- *
- * rgw::io::Accounter came in as a part of rgw::io::AccountingFilter. */
-class RGWRestfulIO : public rgw::io::AccountingFilter<rgw::io::RestfulClient*> {
- std::vector<std::shared_ptr<DecoratedRestfulClient>> filters;
-
-public:
- ~RGWRestfulIO() override = default;
-
- RGWRestfulIO(CephContext *_cx, rgw::io::RestfulClient* engine)
- : AccountingFilter<rgw::io::RestfulClient*>(_cx, std::move(engine)) {
- }
-
- void add_filter(std::shared_ptr<DecoratedRestfulClient> new_filter) {
- new_filter->set_decoratee(this->get_decoratee());
- this->set_decoratee(*new_filter);
- filters.emplace_back(std::move(new_filter));
- }
-}; /* RGWRestfulIO */
-
-
-/* Type conversions to work around lack of req_state type hierarchy matching
- * (e.g.) REST backends (may be replaced w/dynamic typed req_state). */
-static inline rgw::io::RestfulClient* RESTFUL_IO(struct req_state* s) {
- assert(dynamic_cast<rgw::io::RestfulClient*>(s->cio) != nullptr);
-
- return static_cast<rgw::io::RestfulClient*>(s->cio);
-}
-
-static inline rgw::io::Accounter* ACCOUNTING_IO(struct req_state* s) {
- auto ptr = dynamic_cast<rgw::io::Accounter*>(s->cio);
- assert(ptr != nullptr);
-
- return ptr;
-}
-
-static inline RGWRestfulIO* AWS_AUTHv4_IO(const req_state* const s) {
- assert(dynamic_cast<RGWRestfulIO*>(s->cio) != nullptr);
-
- return static_cast<RGWRestfulIO*>(s->cio);
-}
-
-
-class RGWClientIOStreamBuf : public std::streambuf {
-protected:
- RGWRestfulIO &rio;
- size_t const window_size;
- size_t const putback_size;
- std::vector<char> buffer;
-
-public:
- RGWClientIOStreamBuf(RGWRestfulIO &rio, size_t ws, size_t ps = 1)
- : rio(rio),
- window_size(ws),
- putback_size(ps),
- buffer(ws + ps)
- {
- setg(nullptr, nullptr, nullptr);
- }
-
- std::streambuf::int_type underflow() override {
- if (gptr() < egptr()) {
- return traits_type::to_int_type(*gptr());
- }
-
- char * const base = buffer.data();
- char * start;
-
- if (nullptr != eback()) {
- /* We need to skip moving bytes on first underflow. In such case
- * there is simply no previous data we should preserve for unget()
- * or something similar. */
- std::memmove(base, egptr() - putback_size, putback_size);
- start = base + putback_size;
- } else {
- start = base;
- }
-
- size_t read_len = 0;
- try {
- read_len = rio.recv_body(base, window_size);
- } catch (rgw::io::Exception&) {
- return traits_type::eof();
- }
- if (0 == read_len) {
- return traits_type::eof();
- }
-
- setg(base, start, start + read_len);
-
- return traits_type::to_int_type(*gptr());
- }
-};
-
-class RGWClientIOStream : private RGWClientIOStreamBuf, public std::istream {
-/* Inheritance from RGWClientIOStreamBuf is a kind of shadow, undirect
- * form of composition here. We cannot do that explicitly because istream
- * ctor is being called prior to construction of any member of this class. */
-
-public:
- explicit RGWClientIOStream(RGWRestfulIO &s)
- : RGWClientIOStreamBuf(s, 1, 2),
- istream(static_cast<RGWClientIOStreamBuf *>(this)) {
- }
-};
-
-#endif /* CEPH_RGW_CLIENT_IO_H */
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