env/rabbitmq-c/librabbitmq/codegen.py

# Copyright 2007 - 2021, Alan Antonuk and the rabbitmq-c contributors.
# SPDX-License-Identifier: mit


from amqp_codegen import *
import string
import re


class Emitter(object):
    """An object the trivially emits generated code lines.

    This largely exists to be wrapped by more sophisticated emitter
    classes.
    """

    def __init__(self, prefix):
        self.prefix = prefix

    def emit(self, line):
        """Emit a line of generated code."""
        print(self.prefix + line)


class BitDecoder(object):
    """An emitter object that keeps track of the state involved in
    decoding the AMQP bit type."""

    def __init__(self, emitter):
        self.emitter = emitter
        self.bit = 0

    def emit(self, line):
        self.bit = 0
        self.emitter.emit(line)

    def decode_bit(self, lvalue):
        """Generate code to decode a value of the AMQP bit type into
        the given lvalue."""
        if self.bit == 0:
            self.emitter.emit("if (!amqp_decode_8(encoded, &offset, &bit_buffer)) return AMQP_STATUS_BAD_AMQP_DATA;")

        self.emitter.emit("%s = (bit_buffer & (1 << %d)) ? 1 : 0;"
                                                        % (lvalue, self.bit))
        self.bit += 1
        if self.bit == 8:
            self.bit = 0


class BitEncoder(object):
    """An emitter object that keeps track of the state involved in
    encoding the AMQP bit type."""

    def __init__(self, emitter):
        self.emitter = emitter
        self.bit = 0

    def flush(self):
        """Flush the state associated with AMQP bit types."""
        if self.bit:
            self.emitter.emit("if (!amqp_encode_8(encoded, &offset, bit_buffer)) return AMQP_STATUS_BAD_AMQP_DATA;")
            self.bit = 0

    def emit(self, line):
        self.flush()
        self.emitter.emit(line)

    def encode_bit(self, value):
        """Generate code to encode a value of the AMQP bit type from
        the given value."""
        if self.bit == 0:
            self.emitter.emit("bit_buffer = 0;")

        self.emitter.emit("if (%s) bit_buffer |= (1 << %d);"
                                                       % (value, self.bit))
        self.bit += 1
        if self.bit == 8:
            self.flush()


class SimpleType(object):
    """A AMQP type that corresponds to a simple scalar C value of a
    certain width."""

    def __init__(self, bits):
        self.bits = bits
        self.ctype = "uint%d_t" % (bits,)

    def decode(self, emitter, lvalue):
        emitter.emit("if (!amqp_decode_%d(encoded, &offset, &%s)) return AMQP_STATUS_BAD_AMQP_DATA;" % (self.bits, lvalue))

    def encode(self, emitter, value):
        emitter.emit("if (!amqp_encode_%d(encoded, &offset, %s)) return AMQP_STATUS_BAD_AMQP_DATA;" % (self.bits, value))

    def literal(self, value):
        return value

class StrType(object):
    """The AMQP shortstr or longstr types."""

    def __init__(self, lenbits):
        self.lenbits = lenbits
        self.ctype = "amqp_bytes_t"

    def decode(self, emitter, lvalue):
        emitter.emit("{")
        emitter.emit("  uint%d_t len;" % (self.lenbits,))
        emitter.emit("  if (!amqp_decode_%d(encoded, &offset, &len)" % (self.lenbits,))
        emitter.emit("      || !amqp_decode_bytes(encoded, &offset, &%s, len))" % (lvalue,))
        emitter.emit("    return AMQP_STATUS_BAD_AMQP_DATA;")
        emitter.emit("}")

    def encode(self, emitter, value):
        emitter.emit("if (UINT%d_MAX < %s.len" % (self.lenbits, value))
        emitter.emit("    || !amqp_encode_%d(encoded, &offset, (uint%d_t)%s.len)" %
                (self.lenbits, self.lenbits, value))
        emitter.emit("    || !amqp_encode_bytes(encoded, &offset, %s))" % (value,))
        emitter.emit("  return AMQP_STATUS_BAD_AMQP_DATA;")

    def literal(self, value):
        if value != '':
            raise NotImplementedError()

        return "amqp_empty_bytes"

class BitType(object):
    """The AMQP bit type."""

    def __init__(self):
        self.ctype = "amqp_boolean_t"

    def decode(self, emitter, lvalue):
        emitter.decode_bit(lvalue)

    def encode(self, emitter, value):
        emitter.encode_bit(value)

    def literal(self, value):
        return {True: 1, False: 0}[value]

class TableType(object):
    """The AMQP table type."""

    def __init__(self):
        self.ctype = "amqp_table_t"

    def decode(self, emitter, lvalue):
        emitter.emit("{")
        emitter.emit("  int res = amqp_decode_table(encoded, pool, &(%s), &offset);" % (lvalue,))
        emitter.emit("  if (res < 0) return res;")
        emitter.emit("}")

    def encode(self, emitter, value):
        emitter.emit("{")
        emitter.emit("  int res = amqp_encode_table(encoded, &(%s), &offset);" % (value,))
        emitter.emit("  if (res < 0) return res;")
        emitter.emit("}")

    def literal(self, value):
        raise NotImplementedError()

types = {
    'octet': SimpleType(8),
    'short': SimpleType(16),
    'long': SimpleType(32),
    'longlong': SimpleType(64),
    'shortstr': StrType(8),
    'longstr': StrType(32),
    'bit': BitType(),
    'table': TableType(),
    'timestamp': SimpleType(64),
}

def typeFor(spec, f):
    """Get a representation of the AMQP type of a field."""
    return types[spec.resolveDomain(f.domain)]

def c_ize(s):
    s = s.replace('-', '_')
    s = s.replace(' ', '_')
    return s

# When generating API functions corresponding to synchronous methods,
# we need some information that isn't in the protocol def: Some
# methods should not be exposed, indicated here by a False value.
# Some methods should be exposed but certain fields should not be
# exposed as parameters.
apiMethodInfo  = {
    "amqp_connection_start": False, # application code should not use this
    "amqp_connection_secure": False, # application code should not use this
    "amqp_connection_tune": False, # application code should not use this
    "amqp_connection_open": False, # application code should not use this
    "amqp_connection_close": False, # needs special handling
    "amqp_channel_open": ["out_of_band"],
    "amqp_channel_close": False, # needs special handling
    "amqp_access_request": False, # huh?
    "amqp_basic_get": False, # get-ok has content
}

# When generating API functions corresponding to synchronous methods,
# some fields should be suppressed everywhere.  This dict names those
# fields, and the fixed values to use for them.
apiMethodsSuppressArgs = {"ticket": 0, "nowait": False}

AmqpMethod.defName = lambda m: cConstantName(c_ize(m.klass.name) + '_' + c_ize(m.name) + "_method")
AmqpMethod.fullName = lambda m: "amqp_%s_%s" % (c_ize(m.klass.name), c_ize(m.name))
AmqpMethod.structName = lambda m: m.fullName() + "_t"

AmqpClass.structName = lambda c: "amqp_" + c_ize(c.name) + "_properties_t"

def methodApiPrototype(m):
    fn = m.fullName()
    info = apiMethodInfo.get(fn, [])

    docs = "/**\n * %s\n *\n" % (fn)
    docs += " * @param [in] state connection state\n"
    docs += " * @param [in] channel the channel to do the RPC on\n"

    args = []
    for f in m.arguments:
        n = c_ize(f.name)
        if n in apiMethodsSuppressArgs or n in info:
            continue

        args.append(", ")
        args.append(typeFor(m.klass.spec, f).ctype)
        args.append(" ")
        args.append(n)
        docs += " * @param [in] %s %s\n" % (n, n)

    docs += " * @returns %s_ok_t\n" % (fn)
    docs += " */\n"

    return "%sAMQP_EXPORT\n%s_ok_t *\nAMQP_CALL %s(amqp_connection_state_t state, amqp_channel_t channel%s)" % (docs, fn, fn, ''.join(args))

AmqpMethod.apiPrototype = methodApiPrototype

def cConstantName(s):
    return 'AMQP_' + '_'.join(re.split('[- ]', s.upper()))

def cFlagName(c, f):
    return cConstantName(c.name + '_' + f.name) + '_FLAG'

def genErl(spec):
    def fieldTempList(fields):
        return '[' + ', '.join(['F' + str(f.index) for f in fields]) + ']'

    def fieldMapList(fields):
        return ', '.join([c_ize(f.name) + " = F" + str(f.index) for f in fields])

    def genLookupMethodName(m):
        print('    case %s: return "%s";' % (m.defName(), m.defName()))

    def genDecodeMethodFields(m):
        print("    case %s: {" % (m.defName(),))
        print("      %s *m = (%s *) amqp_pool_alloc(pool, sizeof(%s));" % \
            (m.structName(), m.structName(), m.structName()))
        print("      if (m == NULL) { return AMQP_STATUS_NO_MEMORY; }")

        emitter = BitDecoder(Emitter("      "))
        for f in m.arguments:
            typeFor(spec, f).decode(emitter, "m->"+c_ize(f.name))

        print("      *decoded = m;")
        print("      return 0;")
        print("    }")

    def genDecodeProperties(c):
        print("    case %d: {" % (c.index,))
        print("      %s *p = (%s *) amqp_pool_alloc(pool, sizeof(%s));" % \
              (c.structName(), c.structName(), c.structName()))
        print("      if (p == NULL) { return AMQP_STATUS_NO_MEMORY; }")
        print("      p->_flags = flags;")

        emitter = Emitter("      ")
        for f in c.fields:
            emitter.emit("if (flags & %s) {" % (cFlagName(c, f),))
            typeFor(spec, f).decode(emitter, "p->"+c_ize(f.name))
            emitter.emit("}")

        print("      *decoded = p;")
        print("      return 0;")
        print("    }")

    def genEncodeMethodFields(m):
        print("    case %s: {" % (m.defName(),))
        if m.arguments:
            print("      %s *m = (%s *) decoded;" % (m.structName(), m.structName()))

        emitter = BitEncoder(Emitter("      "))
        for f in m.arguments:
            typeFor(spec, f).encode(emitter, "m->"+c_ize(f.name))
        emitter.flush()

        print("      return (int)offset;")
        print("    }")

    def genEncodeProperties(c):
        print("    case %d: {" % (c.index,))
        if c.fields:
            print("      %s *p = (%s *) decoded;" % (c.structName(), c.structName()))

        emitter = Emitter("      ")
        for f in c.fields:
            emitter.emit("      if (flags & %s) {" % (cFlagName(c, f),))
            typeFor(spec, f).encode(emitter, "p->"+c_ize(f.name))
            emitter.emit("}")

        print("      return (int)offset;")
        print("    }")

    methods = spec.allMethods()

    print("""// Copyright 2007 - 2021, Alan Antonuk and the rabbitmq-c contributors.
// SPDX-License-Identifier: mit
    
 /* Generated code. Do not edit. Edit and re-run codegen.py instead. */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "amqp_private.h"
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
""")

    print("""
char const *amqp_constant_name(int constantNumber) {
  switch (constantNumber) {""")
    for (c,v,cls) in spec.constants:
        print("    case %s: return \"%s\";" % (cConstantName(c), cConstantName(c)))
    print("""    default: return "(unknown)";
  }
}""")

    print("""
amqp_boolean_t amqp_constant_is_hard_error(int constantNumber) {
  switch (constantNumber) {""")
    for (c,v,cls) in spec.constants:
        if cls == 'hard-error':
            print("    case %s: return 1;" % (cConstantName(c),))
    print("""    default: return 0;
  }
}""")

    print("""
char const *amqp_method_name(amqp_method_number_t methodNumber) {
  switch (methodNumber) {""")
    for m in methods: genLookupMethodName(m)
    print("""    default: return NULL;
  }
}""")

    print("""
amqp_boolean_t amqp_method_has_content(amqp_method_number_t methodNumber) {
  switch (methodNumber) {""")
    for m in methods:
        if m.hasContent:
            print('    case %s: return 1;' % (m.defName()))
    print("""    default: return 0;
  }
}""")

    print("""
int amqp_decode_method(amqp_method_number_t methodNumber,
                       amqp_pool_t *pool,
                       amqp_bytes_t encoded,
                       void **decoded)
{
  size_t offset = 0;
  uint8_t bit_buffer;

  switch (methodNumber) {""")
    for m in methods: genDecodeMethodFields(m)
    print("""    default: return AMQP_STATUS_UNKNOWN_METHOD;
  }
}""")

    print("""
int amqp_decode_properties(uint16_t class_id,
                           amqp_pool_t *pool,
                           amqp_bytes_t encoded,
                           void **decoded)
{
  size_t offset = 0;

  amqp_flags_t flags = 0;
  int flagword_index = 0;
  uint16_t partial_flags;

  do {
    if (!amqp_decode_16(encoded, &offset, &partial_flags))
      return AMQP_STATUS_BAD_AMQP_DATA;
    flags |= (partial_flags << (flagword_index * 16));
    flagword_index++;
  } while (partial_flags & 1);

  switch (class_id) {""")
    for c in spec.allClasses(): genDecodeProperties(c)
    print("""    default: return AMQP_STATUS_UNKNOWN_CLASS;
  }
}""")

    print("""
int amqp_encode_method(amqp_method_number_t methodNumber,
                       void *decoded,
                       amqp_bytes_t encoded)
{
  size_t offset = 0;
  uint8_t bit_buffer;

  switch (methodNumber) {""")
    for m in methods: genEncodeMethodFields(m)
    print("""    default: return AMQP_STATUS_UNKNOWN_METHOD;
  }
}""")

    print("""
int amqp_encode_properties(uint16_t class_id,
                           void *decoded,
                           amqp_bytes_t encoded)
{
  size_t offset = 0;

  /* Cheat, and get the flags out generically, relying on the
     similarity of structure between classes */
  amqp_flags_t flags = * (amqp_flags_t *) decoded; /* cheating! */

  {
    /* We take a copy of flags to avoid destroying it, as it is used
       in the autogenerated code below. */
    amqp_flags_t remaining_flags = flags;
    do {
      amqp_flags_t remainder = remaining_flags >> 16;
      uint16_t partial_flags = remaining_flags & 0xFFFE;
      if (remainder != 0) { partial_flags |= 1; }
      if (!amqp_encode_16(encoded, &offset, partial_flags))
        return AMQP_STATUS_BAD_AMQP_DATA;
      remaining_flags = remainder;
    } while (remaining_flags != 0);
  }

  switch (class_id) {""")
    for c in spec.allClasses(): genEncodeProperties(c)
    print("""    default: return AMQP_STATUS_UNKNOWN_CLASS;
  }
}""")

    for m in methods:
        if not m.isSynchronous:
            continue

        info = apiMethodInfo.get(m.fullName(), [])
        if info is False:
            continue

        print("")
        print(m.apiPrototype())
        print("{")
        print("  %s req;" % (m.structName(),))

        for f in m.arguments:
            n = c_ize(f.name)

            val = apiMethodsSuppressArgs.get(n)
            if val is None and n in info:
                val = f.defaultvalue

            if val is None:
                val = n
            else:
                val = typeFor(spec, f).literal(val)


            print("  req.%s = %s;" % (n, val))

        reply = cConstantName(c_ize(m.klass.name) + '_' + c_ize(m.name)
                              + "_ok_method")
        print("""
  return amqp_simple_rpc_decoded(state, channel, %s, %s, &req);
}
""" % (m.defName(), reply))

def genHrl(spec):
    def fieldDeclList(fields):
        if fields:
            return ''.join(["  %s %s; /**< %s */\n" % (typeFor(spec, f).ctype,
                                            c_ize(f.name), f.name)
                            for f in fields])
        else:
            return "  char dummy; /**< Dummy field to avoid empty struct */\n"

    def propDeclList(fields):
        return ''.join(["  %s %s;\n" % (typeFor(spec, f).ctype, c_ize(f.name))
                        for f in fields
                        if spec.resolveDomain(f.domain) != 'bit'])

    methods = spec.allMethods()

    print("""// Copyright 2007 - 2021, Alan Antonuk and the rabbitmq-c contributors.
// SPDX-License-Identifier: mit
    
 /* Generated code. Do not edit. Edit and re-run codegen.py instead. */

/** @file rabbitmq-c/framing.h */
#ifndef RABBITMQ_C_FRAMING_H
#define RABBITMQ_C_FRAMING_H

#include <rabbitmq-c/amqp.h>
#include <rabbitmq-c/export.h>

AMQP_BEGIN_DECLS
""")
    print("#define AMQP_PROTOCOL_VERSION_MAJOR %d     /**< AMQP protocol version major */" % (spec.major))
    print("#define AMQP_PROTOCOL_VERSION_MINOR %d     /**< AMQP protocol version minor */" % (spec.minor))
    print("#define AMQP_PROTOCOL_VERSION_REVISION %d  /**< AMQP protocol version revision */" % (spec.revision))
    print("#define AMQP_PROTOCOL_PORT %d              /**< Default AMQP Port */" % (spec.port))

    for (c,v,cls) in spec.constants:
        print("#define %s %s  /**< Constant: %s */" % (cConstantName(c), v, c))
    print("")

    print("""/* Function prototypes. */

/**
 * Get constant name string from constant
 *
 * @param [in] constantNumber constant to get the name of
 * @returns string describing the constant. String is managed by
 *           the library and should not be free()'d by the program
 */
AMQP_EXPORT
char const *
AMQP_CALL amqp_constant_name(int constantNumber);

/**
 * Checks to see if a constant is a hard error
 *
 * A hard error occurs when something severe enough
 * happens that the connection must be closed.
 *
 * @param [in] constantNumber the error constant
 * @returns true if its a hard error, false otherwise
 */
AMQP_EXPORT
amqp_boolean_t
AMQP_CALL amqp_constant_is_hard_error(int constantNumber);

/**
 * Get method name string from method number
 *
 * @param [in] methodNumber the method number
 * @returns method name string. String is managed by the library
 *           and should not be freed()'d by the program
 */
AMQP_EXPORT
char const *
AMQP_CALL amqp_method_name(amqp_method_number_t methodNumber);

/**
 * Check whether a method has content
 *
 * A method that has content will receive the method frame
 * a properties frame, then 1 to N body frames
 *
 * @param [in] methodNumber the method number
 * @returns true if method has content, false otherwise
 */
AMQP_EXPORT
amqp_boolean_t
AMQP_CALL amqp_method_has_content(amqp_method_number_t methodNumber);

/**
 * Decodes a method from AMQP wireformat
 *
 * @param [in] methodNumber the method number for the decoded parameter
 * @param [in] pool the memory pool to allocate the decoded method from
 * @param [in] encoded the encoded byte string buffer
 * @param [out] decoded pointer to the decoded method struct
 * @returns 0 on success, an error code otherwise
 */
AMQP_EXPORT
int
AMQP_CALL amqp_decode_method(amqp_method_number_t methodNumber,
		   amqp_pool_t *pool,
		   amqp_bytes_t encoded,
		   void **decoded);

/**
 * Decodes a header frame properties structure from AMQP wireformat
 *
 * @param [in] class_id the class id for the decoded parameter
 * @param [in] pool the memory pool to allocate the decoded properties from
 * @param [in] encoded the encoded byte string buffer
 * @param [out] decoded pointer to the decoded properties struct
 * @returns 0 on success, an error code otherwise
 */
AMQP_EXPORT
int
AMQP_CALL amqp_decode_properties(uint16_t class_id,
            amqp_pool_t *pool,
            amqp_bytes_t encoded,
            void **decoded);

/**
 * Encodes a method structure in AMQP wireformat
 *
 * @param [in] methodNumber the method number for the decoded parameter
 * @param [in] decoded the method structure (e.g., amqp_connection_start_t)
 * @param [in] encoded an allocated byte buffer for the encoded method
 *              structure to be written to. If the buffer isn't large enough
 *              to hold the encoded method, an error code will be returned.
 * @returns 0 on success, an error code otherwise.
 */
AMQP_EXPORT
int
AMQP_CALL amqp_encode_method(amqp_method_number_t methodNumber,
		   void *decoded,
		   amqp_bytes_t encoded);

/**
 * Encodes a properties structure in AMQP wireformat
 *
 * @param [in] class_id the class id for the decoded parameter
 * @param [in] decoded the properties structure (e.g., amqp_basic_properties_t)
 * @param [in] encoded an allocated byte buffer for the encoded properties to written to.
 *              If the buffer isn't large enough to hold the encoded method, an
 *              an error code will be returned
 * @returns 0 on success, an error code otherwise.
 */
AMQP_EXPORT
int
AMQP_CALL amqp_encode_properties(uint16_t class_id,
		       void *decoded,
		       amqp_bytes_t encoded);
""")

    print("/* Method field records. */\n")
    for m in methods:
        methodid = m.klass.index << 16 | m.index
        print("#define %s ((amqp_method_number_t) 0x%.08X) /**< %s.%s method id @internal %d, %d; %d */" % \
              (m.defName(),
               methodid,
               m.klass.name,
               m.name,
               m.klass.index,
               m.index,
               methodid))
        print("/** %s.%s method fields */\ntypedef struct %s_ {\n%s} %s;\n" % \
              (m.klass.name, m.name, m.structName(), fieldDeclList(m.arguments), m.structName()))

    print("/* Class property records. */")
    for c in spec.allClasses():
        print("#define %s (0x%.04X) /**< %s class id @internal %d */" % \
              (cConstantName(c.name + "_class"), c.index, c.name, c.index))
        index = 0
        for f in c.fields:
            if index % 16 == 15:
                index = index + 1
            shortnum = index // 16
            partialindex = 15 - (index % 16)
            bitindex = shortnum * 16 + partialindex
            print('#define %s (1 << %d) /**< %s.%s property flag */' % (cFlagName(c, f), bitindex, c.name, f.name))
            index = index + 1
        print("/** %s class properties */\ntypedef struct %s_ {\n  amqp_flags_t _flags; /**< bit-mask of set fields */\n%s} %s;\n" % \
              (c.name,
               c.structName(),
               fieldDeclList(c.fields),
               c.structName()))

    print("/* API functions for methods */\n")

    for m in methods:
        if m.isSynchronous and apiMethodInfo.get(m.fullName()) is not False:
            print("%s;" % (m.apiPrototype(),))

    print("""
AMQP_END_DECLS

#endif /* RABBITMQ_C_FRAMING_H */""")

def generateErl(specPath):
    genErl(AmqpSpec(specPath))

def generateHrl(specPath):
    genHrl(AmqpSpec(specPath))

if __name__ == "__main__":
    do_main(generateHrl, generateErl)