Drizzled Public API Documentation

hexdump_transaction_message.cc
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00001 /* - mode: c; c-basic-offset: 2; indent-tabs-mode: nil; -*-
00002  *  vim:expandtab:shiftwidth=2:tabstop=2:smarttab:
00003  *
00004  *  Copyright (C) 2009 Sun Microsystems, Inc.
00005  *
00006  *  Authors:
00007  *
00008  *  Jay Pipes <joinfu@sun.com>
00009  *
00010  *  This program is free software; you can redistribute it and/or modify
00011  *  it under the terms of the GNU General Public License as published by
00012  *  the Free Software Foundation; either version 2 of the License, or
00013  *  (at your option) any later version.
00014  *
00015  *  This program is distributed in the hope that it will be useful,
00016  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
00017  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00018  *  GNU General Public License for more details.
00019  *
00020  *  You should have received a copy of the GNU General Public License
00021  *  along with this program; if not, write to the Free Software
00022  *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
00023  */
00024 
00031 #include <config.h>
00032 #include <drizzled/plugin/function.h>
00033 #include <drizzled/item/func.h>
00034 #include <drizzled/function/str/strfunc.h>
00035 #include <drizzled/error.h>
00036 #include <drizzled/algorithm/crc32.h>
00037 #include <drizzled/internal/my_sys.h>
00038 #include <drizzled/charset.h>
00039 #include <drizzled/errmsg_print.h>
00040 #include <drizzled/gettext.h>
00041 
00042 #include <fcntl.h>
00043 #include <errno.h>
00044 
00045 #include "transaction_log.h"
00046 #include "hexdump_transaction_message.h"
00047 
00048 #include <drizzled/message/transaction.pb.h>
00049 #include <drizzled/util/convert.h>
00050 #include <google/protobuf/io/zero_copy_stream.h>
00051 #include <google/protobuf/io/zero_copy_stream_impl.h>
00052 #include <google/protobuf/io/coded_stream.h>
00053 #include <google/protobuf/text_format.h>
00054 
00055 using namespace std;
00056 using namespace drizzled;
00057 using namespace google;
00058 
00060 extern TransactionLog *transaction_log;
00061 
00062 plugin::Create_function<HexdumpTransactionMessageFunction> *hexdump_transaction_message_func_factory= NULL;
00063 
00064 void HexdumpTransactionMessageFunction::fix_length_and_dec()
00065 {
00066   max_length= 2 * 1024 * 1024; /* 2MB size limit seems ok... */
00067   args[0]->collation.set(
00068     get_charset_by_csname(args[0]->collation.collation->csname,
00069                           MY_CS_BINSORT), DERIVATION_COERCIBLE);
00070 }
00071 
00072 String *HexdumpTransactionMessageFunction::val_str(String *str)
00073 {
00074   assert(fixed == true);
00075 
00076   String *filename_arg= args[0]->val_str(str);
00077   off_t offset_arg= static_cast<int64_t>(args[1]->val_int());
00078 
00079   if (filename_arg == NULL || args[1]->null_value == true)
00080   {
00081     my_error(ER_INVALID_NULL_ARGUMENT, MYF(0), func_name());
00082     null_value= true;
00083     return NULL;
00084   }
00085 
00086   if (transaction_log == NULL)
00087   {
00088     my_error(ER_INVALID_NULL_ARGUMENT, MYF(0), func_name());
00089     null_value= true;
00090     return NULL;
00091   }
00092 
00093   null_value= false;
00094 
00095   message::Transaction transaction_message;
00096 
00103   const string &filename= transaction_log->getLogFilename();
00104   int log_file= open(filename.c_str(), O_RDONLY);
00105   if (log_file == -1)
00106   {
00107     drizzled::sql_perror(_("Failed to open transaction log file"), filename);
00108     null_value= true;
00109 
00110     return NULL;
00111   }
00112 
00113   (void) lseek(log_file, offset_arg, SEEK_SET);
00114 
00115   protobuf::io::FileInputStream *file_input= new protobuf::io::FileInputStream(log_file);
00116   file_input->SetCloseOnDelete(true);
00117 
00118   protobuf::io::CodedInputStream *coded_input= new protobuf::io::CodedInputStream(file_input);
00119 
00120   /* Grab our message type and length */
00121   uint32_t message_type;
00122   if (! coded_input->ReadLittleEndian32(&message_type))
00123   {
00124     delete file_input;
00125 
00127     null_value= true;
00128     return NULL;
00129   }
00130 
00131   uint32_t message_size;
00132   if (! coded_input->ReadLittleEndian32(&message_size))
00133   {
00134     delete file_input;
00135 
00137     null_value= true;
00138     return NULL;
00139   }
00140 
00141   uint8_t *buffer= (uint8_t *) malloc(message_size);
00142 
00143   bool result= coded_input->ReadRaw(buffer, message_size);
00144   if (result == false)
00145   {
00146     char errmsg[STRERROR_MAX];
00147     strerror_r(errno, errmsg, sizeof(errmsg));
00148     fprintf(stderr, _("Could not read transaction message.\n"));
00149     fprintf(stderr, _("GPB ERROR: %s.\n"), errmsg);
00150     fprintf(stderr, _("Raw buffer read: %s.\n"), buffer);
00151   }
00152 
00153   /*
00154    * Convert raw bytes to a hex representation and store back into
00155    * the return String.
00156    */
00157   string hexdump;
00158   hexdump.reserve(message_size * 4);
00159   bytesToHexdumpFormat(hexdump, reinterpret_cast<const unsigned char *>(buffer), message_size);
00160 
00161   /* 
00162    * Check that the transaction message is actually not corrupt before
00163    * printing out the raw byte representation of the transaction message...
00164    */
00165   result= transaction_message.ParseFromArray(buffer, static_cast<int32_t>(message_size));
00166   if (result == false)
00167   {
00168     fprintf(stderr, _("Unable to parse transaction. Got error: %s.\n"), transaction_message.InitializationErrorString().c_str());
00169     if (buffer != NULL)
00170       fprintf(stderr, _("BUFFER: %s\n"), buffer);
00171   }
00172 
00173   if (str->alloc(message_size * 4)) /* Hex representation is ~4 times number of bytes */
00174   {
00175     null_value= true;
00176     return NULL;
00177   }
00178 
00179   strncpy(str->ptr(), hexdump.c_str(), hexdump.length());
00180   str->length(hexdump.length());
00181 
00182   free(buffer);
00183 
00184   delete coded_input;
00185   delete file_input;
00186 
00187   return str;
00188 }