Cosmetic improvements.

[invirt/third/libt4.git] / rpc / marshall.h

diff --git a/rpc/marshall.h b/rpc/marshall.h
index 7a85d6b..7b716e2 100644 (file)
--- a/rpc/marshall.h
+++ b/rpc/marshall.h
@@ -1,376 +1,249 @@
 #ifndef marshall_h
 #define marshall_h
 
 #ifndef marshall_h
 #define marshall_h
 

-#include <iostream>
-#include <sstream>
-#include <string>
-#include <vector>
-#include <map>
-#include <stdlib.h>
-#include <string.h>
-#include <cstddef>
-#include <inttypes.h>
-#include "lang/verify.h"
-
-struct request_header {
-    request_header(int x=0, int p=0, int c=0, int s=0, int xi=0) :
-        xid(x), proc(p), clt_nonce(c), srv_nonce(s), xid_rep(xi) {}
-    int xid;
-    int proc;
-    unsigned int clt_nonce;
-    unsigned int srv_nonce;
-    int xid_rep;
-    request_header hton() const {
-        return {
-            htonl(xid), htonl(proc), htonl(clt_nonce), htonl(srv_nonce), htonl(xid_rep)
-        };
-    }
-};
-
-struct reply_header {
-    reply_header(int x=0, int r=0): xid(x), ret(r) {}
-    int xid;
-    int ret;
-    reply_header hton() const {
-        return {
-            htonl(xid), htonl(ret)
-        };
-    }
-};
-
-typedef int rpc_sz_t;
+#include "types.h"
+#include "rpc_protocol.h"

 
 

-//size of initial buffer allocation
-#define DEFAULT_RPC_SZ 1024
-#define RPC_HEADER_SZ (std::max(sizeof(request_header), sizeof(reply_header)) + sizeof(rpc_sz_t))
+//
+// Marshall and unmarshall objects
+//

 
 class marshall {
     private:
 
 class marshall {
     private:

-        char *buf_;     // Base of the raw bytes buffer (dynamically readjusted)
-        size_t capacity_;  // Capacity of the buffer
-        size_t index_;     // Read/write head position
-
-        inline void reserve(size_t n) {
-            if((index_+n) > capacity_){
-                capacity_ += std::max(capacity_, n);
-                VERIFY (buf_ != NULL);
-                buf_ = (char *)realloc(buf_, capacity_);
-                VERIFY(buf_);
-            }
-        }
-    public:
-        struct pass { template <typename... Args> inline pass(Args&&...) {} };
+        string buf_ = string(rpc_protocol::DEFAULT_RPC_SZ, 0); // Raw bytes buffer
+        size_t index_ = rpc_protocol::RPC_HEADER_SZ; // Read/write head position

 
 

+    public:

         template <typename... Args>
         template <typename... Args>

-
-        marshall(const Args&... args) {
-            buf_ = (char *) malloc(sizeof(char)*DEFAULT_RPC_SZ);
-            VERIFY(buf_);
-            capacity_ = DEFAULT_RPC_SZ;
-            index_ = RPC_HEADER_SZ;
+        marshall(const Args & ... args) {

             (void)pass{(*this << args)...};
         }
 
             (void)pass{(*this << args)...};
         }
 

-        ~marshall() {
-            if (buf_)
-                free(buf_);
-        }
-
-        int size() { return index_;}
-        char *cstr() { return buf_;}
-        const char *cstr() const { return buf_;}
-
-        void rawbyte(unsigned char x) {
-            reserve(1);
-            buf_[index_++] = x;
-        }
-
-        void rawbytes(const char *p, int n) {
-            reserve(n);
-            memcpy(buf_+index_, p, n);
+        void rawbytes(const void *p, size_t n) {
+            if (index_+n > buf_.size())
+                buf_.resize(index_+n);
+            copy((char *)p, (char *)p+n, &buf_[index_]);

             index_ += n;
         }
 
             index_ += n;
         }
 

-        // Return the current content (excluding header) as a string
-        std::string get_content() {
-            return std::string(buf_+RPC_HEADER_SZ,index_-RPC_HEADER_SZ);
-        }
-
-        // Return the current content (excluding header) as a string
-        std::string str() {
-            return get_content();
-        }
-
-        void pack_req_header(const request_header &h);
-        void pack_reply_header(const reply_header &h);
-
-        void take_buf(char **b, int *s) {
-            *b = buf_;
-            *s = index_;
-            buf_ = NULL;
+        // with header
+        inline operator string() const { return buf_.substr(0,index_); }
+        // without header
+        inline string content() const { return buf_.substr(rpc_protocol::RPC_HEADER_SZ,index_-rpc_protocol::RPC_HEADER_SZ); }
+
+        // letting S be a defaulted template parameter forces the compiler to
+        // delay looking up operator<<(marshall &, rpc_sz_t) until we define it
+        // (i.e. we define an operator for marshalling uint32_t)
+        template <class T, class S=rpc_protocol::rpc_sz_t> inline void
+        pack_header(const T & h) {
+            VERIFY(sizeof(T)+sizeof(S) <= rpc_protocol::RPC_HEADER_SZ);
+            size_t saved_sz = index_;

             index_ = 0;
             index_ = 0;

-            return;
+            *this << (S)(saved_sz - sizeof(S)) << (T)h;
+            index_ = saved_sz;

         }
 };
 
         }
 };
 

-marshall& operator<<(marshall &, bool);
-marshall& operator<<(marshall &, unsigned int);
-marshall& operator<<(marshall &, int);
-marshall& operator<<(marshall &, unsigned char);
-marshall& operator<<(marshall &, char);
-marshall& operator<<(marshall &, unsigned short);
-marshall& operator<<(marshall &, short);
-marshall& operator<<(marshall &, unsigned long long);
-marshall& operator<<(marshall &, const std::string &);
-
-template <class A> marshall &
-operator<<(marshall &m, const A &x) {
-    m << (unsigned int) x.size();
-    for (const auto &a : x)
-        m << a;
-    return m;
-}
-
-template <class A, class B> marshall &
-operator<<(marshall &m, const std::pair<A,B> &d) {
-    m << d.first;
-    m << d.second;
-    return m;
-}
-

 class unmarshall {
     private:
 class unmarshall {
     private:

-        char *buf_;
-        int sz_;
-        int index_;
-        bool ok_;
+        string buf_;
+        size_t index_ = 0;
+        bool ok_ = false;

 
 

-        inline bool ensure(size_t n);

     public:
     public:

-        unmarshall(): buf_(NULL),sz_(0),index_(0),ok_(false) {}
-        unmarshall(char *b, int sz): buf_(b),sz_(sz),index_(),ok_(true) {}
-        unmarshall(const std::string &s) : buf_(NULL),sz_(0),index_(0),ok_(false)
-        {
-            //take the content which does not exclude a RPC header from a string
-            take_content(s);
-        }
-        ~unmarshall() {
-            if (buf_) free(buf_);
-        }
-
-        //take contents from another unmarshall object
-        void take_in(unmarshall &another);
-
-        //take the content which does not exclude a RPC header from a string
-        void take_content(const std::string &s) {
-            sz_ = s.size()+RPC_HEADER_SZ;
-            buf_ = (char *)realloc(buf_,sz_);
-            VERIFY(buf_);
-            index_ = RPC_HEADER_SZ;
-            memcpy(buf_+index_, s.data(), s.size());
-            ok_ = true;
+        template <typename... Args>
+        unmarshall(const string & s, bool has_header, Args && ... args)
+            : buf_(s),index_(rpc_protocol::RPC_HEADER_SZ) {
+            if (!has_header)
+                buf_.insert(0, rpc_protocol::RPC_HEADER_SZ, 0);
+            ok_ = (buf_.size() >= rpc_protocol::RPC_HEADER_SZ);
+            (void)pass{(*this >> args)...};

         }
 
         bool ok() const { return ok_; }
         }
 
         bool ok() const { return ok_; }

-        char *cstr() { return buf_;}
-        bool okdone() const { return ok_ && index_ == sz_; }
-
-        unsigned int rawbyte();
-        void rawbytes(std::string &s, size_t n);
-
-        int ind() { return index_;}
-        int size() { return sz_;}
-        void unpack(int *); //non-const ref
-        void take_buf(char **b, int *sz) {
-            *b = buf_;
-            *sz = sz_;
-            sz_ = index_ = 0;
-            buf_ = NULL;
-        }
+        bool okdone() const { return ok_ && index_ == buf_.size(); }

 
 

-        void unpack_req_header(request_header *h) {
-            //the first 4-byte is for channel to fill size of pdu
-            index_ = sizeof(rpc_sz_t);
-            unpack(&h->xid);
-            unpack(&h->proc);
-            unpack((int *)&h->clt_nonce);
-            unpack((int *)&h->srv_nonce);
-            unpack(&h->xid_rep);
-            index_ = RPC_HEADER_SZ;
+        void rawbytes(void * t, size_t n) {
+            if (index_+n > buf_.size())
+                ok_ = false;
+            VERIFY(ok_);
+            copy(&buf_[index_], &buf_[index_+n], (char *)t);
+            index_ += n;

         }
 
         }
 

-        void unpack_reply_header(reply_header *h) {
-            //the first 4-byte is for channel to fill size of pdu
-            index_ = sizeof(rpc_sz_t);
-            unpack(&h->xid);
-            unpack(&h->ret);
-            index_ = RPC_HEADER_SZ;
+        template <class T> inline void
+        unpack_header(T & h) {
+            VERIFY(sizeof(T)+sizeof(rpc_protocol::rpc_sz_t) <= rpc_protocol::RPC_HEADER_SZ);
+            // first 4 bytes hold length field
+            index_ = sizeof(rpc_protocol::rpc_sz_t);
+            *this >> h;
+            index_ = rpc_protocol::RPC_HEADER_SZ;

         }
 
         }
 

-        template <class A>
-        inline A grab() {
-            A a;
-            *this >> a;
-            return a;
-        }
+        template <class T> inline T _grab() { T t; *this >> t; return t; }

 };
 
 };
 

-template <class A> unmarshall & operator>>(unmarshall &u, A &x) {
-    unsigned n = u.grab<unsigned>();
-    x.clear();
-    while (n--)
-        x.emplace_back(u.grab<typename A::value_type>());
-    return u;
+//
+// Marshalling for plain old data
+//
+
+#define MARSHALL_RAW_NETWORK_ORDER_AS(_c_, _d_) \
+inline marshall & operator<<(marshall & m, _c_ x) { _d_ y = hton((_d_)x); m.rawbytes(&y, sizeof(_d_)); return m; } \
+inline unmarshall & operator>>(unmarshall & u, _c_ & x) { _d_ y; u.rawbytes(&y, sizeof(_d_)); x = (_c_)ntoh(y); return u; }
+
+#define MARSHALL_RAW_NETWORK_ORDER(_c_) MARSHALL_RAW_NETWORK_ORDER_AS(_c_, _c_)
+
+MARSHALL_RAW_NETWORK_ORDER_AS(bool, uint8_t)
+MARSHALL_RAW_NETWORK_ORDER(uint8_t)
+MARSHALL_RAW_NETWORK_ORDER(int8_t)
+MARSHALL_RAW_NETWORK_ORDER(uint16_t)
+MARSHALL_RAW_NETWORK_ORDER(int16_t)
+MARSHALL_RAW_NETWORK_ORDER(uint32_t)
+MARSHALL_RAW_NETWORK_ORDER(int32_t)
+MARSHALL_RAW_NETWORK_ORDER_AS(size_t, uint32_t)
+MARSHALL_RAW_NETWORK_ORDER(uint64_t)
+MARSHALL_RAW_NETWORK_ORDER(int64_t)
+
+//
+// Marshalling for tuples (used to implement marshalling for structs)
+//
+
+// In order to iterate over the tuple elements, we first need a template
+// parameter pack containing the tuple's indices.  The function templates named
+// *_imp below accept an empty tag struct as their last argument, and use its
+// template arguments to index the tuple.  The operator<< overloads instantiate
+// the appropriate tag struct to make this possible.
+
+template <class... Args, size_t... Indices> inline marshall &
+tuple_marshall_imp(marshall & m, tuple<Args...> & t, tuple_indices<Indices...>) {
+    // Note that brace initialization is used for the empty structure "pack",
+    // forcing the comma-separated expressions expanded from the parameter pack
+    // to be evaluated in order.  Order matters because the elements must be
+    // serialized consistently!  The empty struct resulting from construction
+    // is discarded.
+    (void)pass{(m << get<Indices>(t))...};
+    return m;

 }
 
 }
 

-template <class A, class B> unmarshall &
-operator>>(unmarshall &u, std::map<A,B> &x) {
-    unsigned n = u.grab<unsigned>();
-    x.clear();
-    while (n--)
-        x.emplace(u.grab<std::pair<A,B>>());
-    return u;
+template <class... Args> marshall &
+operator<<(marshall & m, tuple<Args...> && t) {
+    using Indices = typename make_tuple_indices<sizeof...(Args)>::type;
+    return tuple_marshall_imp(m, t, Indices());

 }
 
 }
 

-template <class A, class B> unmarshall &
-operator>>(unmarshall &u, std::pair<A,B> &d) {
-    return u >> d.first >> d.second;
+template <class... Args, size_t... Indices> inline unmarshall &
+tuple_unmarshall_imp(unmarshall & u, tuple<Args & ...> t, tuple_indices<Indices...>) {
+    (void)pass{(u >> get<Indices>(t))...};
+    return u;

 }
 
 }
 

-typedef std::function<int(unmarshall &, marshall &)> handler;
+template <class... Args> unmarshall &
+operator>>(unmarshall & u, tuple<Args & ...> && t) {
+    using Indices = typename make_tuple_indices<sizeof...(Args)>::type;
+    return tuple_unmarshall_imp(u, t, Indices());
+}

 
 //
 
 //

-// Automatic marshalling wrappers for RPC handlers
+// Marshalling for structs or classes containing a MEMBERS declaration

 //
 
 //
 

-// PAI 2013/09/19
-// C++11 does neither of these two things for us:
-// 1) Declare variables using a parameter pack expansion, like so
-//      Args ...args;
-// 2) Call a function with a std::tuple of the arguments it expects
+// Implements struct marshalling via tuple marshalling of members.
+#define MARSHALLABLE_STRUCT(_c_) \
+inline unmarshall & operator>>(unmarshall & u, _c_ & a) { return u >> a._tuple_(); } \
+inline marshall & operator<<(marshall & m, const _c_ a) { return m << a._tuple_(); }
+
+// our first two marshallable structs...
+MARSHALLABLE_STRUCT(rpc_protocol::request_header)
+MARSHALLABLE_STRUCT(rpc_protocol::reply_header)
+

 //
 //

-// We implement an 'invoke' function for functions of the RPC handler
-// signature, i.e. int(R & r, const Args...)
+// Marshalling for STL containers

 //
 //

-// One thing we need in order to accomplish this is a way to cause the compiler
-// to specialize 'invoke' with a parameter pack containing a list of indices
-// for the elements of the tuple.  This will allow us to call the underlying
-// function with the exploded contents of the tuple.  The empty type
-// tuple_indices<size_t...> accomplishes this.  It will be passed in to
-// 'invoke' as a parameter which will be ignored, but its type will force the
-// compiler to specialize 'invoke' appropriately.
-
-// The following implementation of tuple_indices is redistributed under the MIT
-// License as an insubstantial portion of the LLVM compiler infrastructure.
-
-template <size_t...> struct tuple_indices {};
-template <size_t S, class IntTuple, size_t E> struct make_indices_imp;
-template <size_t S, size_t ...Indices, size_t E> struct make_indices_imp<S, tuple_indices<Indices...>, E> {
-    typedef typename make_indices_imp<S+1, tuple_indices<Indices..., S>, E>::type type;
-};
-template <size_t E, size_t ...Indices> struct make_indices_imp<E, tuple_indices<Indices...>, E> {
-    typedef tuple_indices<Indices...> type;
-};
-template <size_t E, size_t S=0> struct make_tuple_indices {
-    typedef typename make_indices_imp<S, tuple_indices<>, E>::type type;
-};
-
-// This class encapsulates the default response to runtime unmarshalling
-// failures.  The templated wrappers below may optionally use a different
-// class.

 
 

-struct VerifyOnFailure {
-    static inline int unmarshall_args_failure() {
-        VERIFY(0);
-        return 0;
-    }
-};
+// this overload is visible for type A only if A::cbegin and A::cend exist
+template <class A> inline typename
+enable_if<is_const_iterable<A>::value, marshall>::type &
+operator<<(marshall & m, const A & x) {
+    m << (unsigned int)x.size();
+    for (const auto & a : x)
+        m << a;
+    return m;
+}

 
 

-// Here's the implementation of 'invoke'.  It could be more general, but this
-// meets our needs.
+// visible for type A if A::emplace_back(a) makes sense
+template <class A> inline typename
+enable_if<supports_emplace_back<A>::value, unmarshall>::type &
+operator>>(unmarshall & u, A & x) {
+    unsigned n = u._grab<unsigned>();
+    x.clear();
+    while (n--)
+        x.emplace_back(u._grab<typename A::value_type>());
+    return u;
+}

 
 

-// One for function pointers...
+// std::pair<A, B>
+template <class A, class B> inline marshall &
+operator<<(marshall & m, const pair<A,B> & d) {
+    return m << d.first << d.second;
+}

 
 

-template <class F, class R, class args_type, size_t ...Indices>
-typename std::enable_if<!std::is_member_function_pointer<F>::value, int>::type
-invoke(F f, void *, R & r, args_type & t, tuple_indices<Indices...>) {
-    return f(r, std::move(std::get<Indices>(t))...);
+template <class A, class B> inline unmarshall &
+operator>>(unmarshall & u, pair<A,B> & d) {
+    return u >> d.first >> d.second;

 }
 
 }
 

-// And one for pointers to member functions...
+// std::map<A, B>
+template <class A, class B> inline unmarshall &
+operator>>(unmarshall & u, map<A,B> & x) {
+    unsigned n = u._grab<unsigned>();
+    x.clear();
+    while (n--)
+        x.emplace(u._grab<pair<A,B>>());
+    return u;
+}

 
 

-template <class F, class C, class R, class args_type, size_t ...Indices>
-typename std::enable_if<std::is_member_function_pointer<F>::value, int>::type
-invoke(F f, C *c, R & r, args_type & t, tuple_indices<Indices...>) {
-    return (c->*f)(r, std::move(std::get<Indices>(t))...);
+// std::string
+inline marshall & operator<<(marshall & m, const string & s) {
+    m << (uint32_t)s.size();
+    m.rawbytes(s.data(), s.size());
+    return m;

 }
 
 }
 

-// The class marshalled_func_imp uses partial template specialization to
-// implement the ::wrap static function.  ::wrap takes a function pointer or a
-// pointer to a member function and returns a handler * object which
-// unmarshalls arguments, verifies successful unmarshalling, calls the supplied
-// function, and marshalls the response.
-
-template <class Functor, class Instance, class Signature,
-          class ErrorHandler=VerifyOnFailure> struct marshalled_func_imp;
-
-// Here we specialize on the Signature template parameter to obtain the list of
-// argument types.  Note that we do not assume that the Functor parameter has
-// the same pattern as Signature; this allows us to ignore the distinctions
-// between various types of callable objects at this level of abstraction.
-
-template <class F, class C, class ErrorHandler, class R, class... Args>
-struct marshalled_func_imp<F, C, int(R&, Args...), ErrorHandler> {
-    static inline handler *wrap(F f, C *c=nullptr) {
-        // This type definition corresponds to an empty struct with
-        // template parameters running from 0 up to (# args) - 1.
-        using Indices = typename make_tuple_indices<sizeof...(Args)>::type;
-        // This type definition represents storage for f's unmarshalled
-        // arguments.  std::decay is (most notably) stripping off const
-        // qualifiers.
-        using ArgsStorage = std::tuple<typename std::decay<Args>::type...>;
-        // Allocate a handler (i.e. std::function) to hold the lambda
-        // which will unmarshall RPCs and call f.
-        return new handler([=](unmarshall &u, marshall &m) -> int {
-            // Unmarshall each argument with the correct type and store the
-            // result in a tuple.
-            ArgsStorage t = {u.grab<typename std::decay<Args>::type>()...};
-            // Verify successful unmarshalling of the entire input stream.
-            if (!u.okdone())
-                return ErrorHandler::unmarshall_args_failure();
-            // Allocate space for the RPC response -- will be passed into the
-            // function as an lvalue reference.
-            R r;
-            // Perform the invocation.  Note that Indices() calls the default
-            // constructor of the empty struct with the special template
-            // parameters.
-            int b = invoke(f, c, r, t, Indices());
-            // Marshall the response.
-            m << r;
-            // Make like a tree.
-            return b;
-        });
+inline unmarshall & operator>>(unmarshall & u, string & s) {
+    uint32_t sz = u._grab<uint32_t>();
+    if (u.ok()) {
+        s.resize(sz);
+        u.rawbytes(&s[0], sz);

     }
     }

-};
+    return u;
+}

 
 

-// More partial template specialization shenanigans to reduce the number of
-// parameters which must be provided explicitly and to support a few common
-// callable types.  C++11 doesn't allow partial function template
-// specialization, so we use classes (structs).
+//
+// Marshalling for strongly-typed enums
+//

 
 

-template <class Functor, class ErrorHandler=VerifyOnFailure,
-    class Signature=Functor> struct marshalled_func;
+template <class E> typename enable_if<is_enum<E>::value, marshall>::type &
+operator<<(marshall & m, E e) {
+    return m << from_enum(e);
+}

 
 

-template <class F, class ErrorHandler, class... Args>
-struct marshalled_func<F, ErrorHandler, int(*)(Args...)> :
-    public marshalled_func_imp<F, void, int(Args...), ErrorHandler> {};
+template <class E> typename enable_if<is_enum<E>::value, unmarshall>::type &
+operator>>(unmarshall & u, E & e) {
+    e = to_enum<E>(u._grab<enum_type_t<E>>());
+    return u;
+}

 
 

-template <class F, class ErrorHandler, class C, class... Args>
-struct marshalled_func<F, ErrorHandler, int(C::*)(Args...)> :
-    public marshalled_func_imp<F, C, int(Args...), ErrorHandler> {};
+//
+// Recursive marshalling
+//
+
+inline marshall & operator<<(marshall & m, marshall & n) {
+    return m << n.content();
+}

 
 

-template <class F, class ErrorHandler, class Signature>
-struct marshalled_func<F, ErrorHandler, std::function<Signature>> :
-    public marshalled_func_imp<F, void, Signature, ErrorHandler> {};
+inline unmarshall & operator>>(unmarshall & u, unmarshall & v) {
+    v = unmarshall(u._grab<string>(), false);
+    return u;
+}

 
 #endif
 
 #endif