1 | ###########################################################################
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2 | #
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3 | # HDThriftFS.pm -- file functions acting upon a HDFS via thrift
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4 | #
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5 | # A component of the Greenstone digital library software
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6 | # from the New Zealand Digital Library Project at the
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7 | # University of Waikato, New Zealand.
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8 | #
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9 | # Copyright (C) 2013 New Zealand Digital Library Project
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10 | #
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11 | # This program is free software; you can redistribute it and/or modify
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12 | # it under the terms of the GNU General Public License as published by
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13 | # the Free Software Foundation; either version 2 of the License, or
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14 | # (at your option) any later version.
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15 | #
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16 | # This program is distributed in the hope that it will be useful,
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17 | # but WITHOUT ANY WARRANTY; without even the implied warranty of
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18 | # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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19 | # GNU General Public License for more details.
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20 | #
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21 | # You should have received a copy of the GNU General Public License
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22 | # along with this program; if not, write to the Free Software
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23 | # Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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24 | #
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25 | ###########################################################################
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26 |
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27 | ################################################################################
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28 | ## An Object wrapped around a HDThrift file handle usable as a Perl Handle ##
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29 | ################################################################################
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30 |
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31 | package FileUtils::HDThriftFS::ThriftFH;
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32 |
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33 | require Tie::Handle;
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34 |
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35 | use base 'Tie::Handle';
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36 | use Devel::Peek;
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37 | use MIME::Base91;
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38 |
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39 | my $debug_encoding = 0;
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40 |
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41 | sub TIEHANDLE
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42 | {
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43 | my $class = shift;
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44 | my $thrift_client = shift;
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45 | my $self = {};
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46 | $self->{'buffer_length'} = 4096; # 4k blocks
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47 | $self->{'client'} = $thrift_client;
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48 | $self->{'fh'} = 0;
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49 | $self->{'file_length'} = 0;
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50 | $self->{'mode'} = 'r';
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51 | $self->{'read_offset'} = 0; # A read offset
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52 | $self->{'warnings'} = {'binmode' => 0};
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53 | return bless $self, $class;
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54 | }
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55 |
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56 | sub WRITE
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57 | {
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58 | my $self = shift;
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59 | my ($scalar, $length, $offset) = @_;
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60 | print STDERR "ThriftFH::WRITE() - implement me!\n";
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61 | }
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62 |
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63 | sub PRINT
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64 | {
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65 | my $self = shift;
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66 | my $result = 0;
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67 | # only available in write or append modes
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68 | if ($self->{'mode'} eq 'w' || $self->{'mode'} eq 'a')
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69 | {
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70 | foreach my $decoded_buffer (@_)
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71 | {
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72 | if ($debug_encoding)
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73 | {
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74 | print STDERR "Print String: \n=== START ===\n"; Dump($decoded_buffer); print STDERR "\n=== END ===\n\n";
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75 | }
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76 | # We now need to Base91 encode everything sent through to Thrift Server
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77 | my $encoded_buffer = MIME::Base91::encode($decoded_buffer);
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78 | if ($debug_encoding)
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79 | {
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80 | print STDERR "Encoded String: \n=== START ===\n"; Dump($encoded_buffer); print STDERR "\n=== END ===\n\n";
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81 | }
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82 | $self->{'client'}->write($self->{'fh'}, $encoded_buffer);
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83 | }
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84 | $result = 1;
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85 | }
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86 | return $result;
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87 | }
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88 |
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89 | sub PRINTF
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90 | {
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91 | my $self = shift;
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92 | my $format = shift;
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93 | print STDERR "ThriftFH::PRINTF() - implement me!\n";
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94 | }
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95 |
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96 | sub READ
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97 | {
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98 | my $self = shift;
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99 | my ($scalar_ref, $length, $offset) = @_;
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100 | my $bytes_read = 0;
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101 | if (!$self->{'eof'} && $self->{'mode'} eq 'r')
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102 | {
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103 | my $encoded_buffer = $self->{'client'}->read($self->{'fh'}, $offset, $length);
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104 | if ($debug_encoding)
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105 | {
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106 | print STDERR "Read String: \n=== START ===\n"; Dump($encoded_buffer); print STDERR "\n=== END ===\n\n";
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107 | }
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108 | my $decoded_buffer = MIME::Base91::decode($encoded_buffer);
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109 | if ($debug_encoding)
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110 | {
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111 | print STDERR "Decoded String: \n=== START ===\n"; Dump($decoded_buffer); print STDERR "\n=== END ===\n\n";
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112 | }
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113 | $bytes_read = scalar($decoded_buffer);
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114 | # the only way I can see to modify the callers version of $scalar
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115 | $_[0] = $decoded_buffer;
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116 | }
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117 | return $bytes_read;
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118 | }
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119 |
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120 | sub READLINE
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121 | {
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122 | my $self = shift;
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123 | #rint "ThriftFH:READLINE()\n";
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124 | #rint " - file_length=" . $self->{'file_length'} . "\n";
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125 | my $line = undef;
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126 | # out of file? out of lines!
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127 | # not in read mode - can't read!
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128 | if (!$self->{'eof'} && $self->{'mode'} eq 'r')
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129 | {
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130 | my $found_line = 0;
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131 | my $search_offset = $self->{'read_offset'};
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132 | my $search_eof = $self->{'eof'};
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133 | # grab a 'buffer' of data starting at my current read offset
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134 | #rint "->read(fh, $search_offset, " . $self->{'buffer_length'} . ")\n";
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135 | my $encoded_buffer = $self->{'client'}->read($self->{'fh'}, $search_offset, $self->{'buffer_length'});
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136 | my $decoded_buffer = MIME::Base91::decode($encoded_buffer);
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137 | #rint " - buffer=|" . $decoded_buffer . "|\n";
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138 | if (length($decoded_buffer) < $self->{'buffer_length'} || ($self->{'read_offset'} + length($decoded_buffer)) < $self->{'file_length'})
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139 | {
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140 | $search_eof = 1;
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141 | }
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142 | while (!$search_eof && index($decoded_buffer, "\n") == -1)
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143 | {
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144 | #rint " * no newline found yet - filling buffer...\n";
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145 | $search_offset = $self->{'read_offset'} + length($decoded_buffer);
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146 | #rint "->read(fh, $search_offset, " . $self->{'buffer_length'} . ")\n";
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147 | my $more_encoded_buffer = $self->{'client'}->read($self->{'fh'}, $search_offset, $self->{'buffer_length'});
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148 | my $more_decoded_buffer = MIME::Base91::decode($more_encoded_buffer);
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149 | #rint " - more_buffer=|" . $more_decoded_buffer . "|\n";
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150 | $decoded_buffer .= $more_decoded_buffer;
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151 | #rint " - buffer=|" . $decoded_buffer. "|\n";
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152 | # if I read less than I asked for, or my next search offset is beyond the
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153 | # end of the file, then I've run out of 'file'
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154 | if (length($more_decoded_buffer) < $self->{'buffer_length'} || ($self->{'read_offset'} + length($decoded_buffer)) < $self->{'file_length'})
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155 | {
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156 | $search_eof = 1;
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157 | #rint " * found eof!\n";
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158 | }
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159 | }
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160 | # if buffer contains newline, then we only return a fragment of buffer and
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161 | # update the offset
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162 | my $newline_offset = index($decoded_buffer, "\n");
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163 | if ($newline_offset > -1)
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164 | {
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165 | #rint " * found newline - returning part of buffer\n";
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166 | $line = substr($decoded_buffer, 0, $newline_offset + 1);
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167 | # rest of buffer ignored
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168 | }
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169 | # otherwise we return all of buffer and mark the file as eof
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170 | else
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171 | {
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172 | #rint " * no newline found - returning all of buffer\n";
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173 | $line = $decoded_buffer;
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174 | $self->{'eof'} = 1; # out of file
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175 | }
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176 | # move the read pointer by however much we read (in either case)
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177 | $self->{'read_offset'} += length($line);
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178 | #rint " => |" . $line . "|\n\n";
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179 | }
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180 | return $line;
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181 | }
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182 |
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183 | sub GETC
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184 | {
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185 | my $self = shift;
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186 | print STDERR "ThriftFH::GETC() - implement me!\n";
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187 | return '';
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188 | }
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189 |
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190 | sub CLOSE
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191 | {
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192 | my $self = shift;
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193 | $self->{'client'}->close($self->{'fh'});
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194 | $self->{'fh'} = 0;
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195 | return 1;
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196 | }
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197 |
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198 |
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199 | ## @function open()
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200 | #
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201 | sub OPEN
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202 | {
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203 | my $self = shift;
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204 | my $path = shift;
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205 | my $mode = shift;
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206 | if (!defined $mode)
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207 | {
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208 | $mode = '<'; # Default to read as that's least destructive
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209 | }
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210 | #rint STDERR "DEBUG: ThriftFH::OPEN(self, $path, $mode)\n";
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211 | # write mode always creates a new file - clobbering any existing
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212 | if ($mode eq 'w' || $mode eq '>')
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213 | {
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214 | # if file already exists, create() will (eventually) fail - so we need to
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215 | # ensure it doesn't already exist beforehand
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216 | if ($self->{'client'}->exists($path))
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217 | {
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218 | $self->{'client'}->rm ($path);
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219 | }
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220 | $self->{'fh'} = $self->{'client'}->create($path);
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221 | $self->{'mode'} = 'w'; # writing
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222 | }
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223 | else
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224 | {
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225 | # open will fail if the file doesn't already exist - so we may
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226 | # need to create it beforehand
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227 | if (!$self->{'client'}->exists($path))
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228 | {
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229 | $self->{'fh'} = $self->{'client'}->create($path);
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230 | $self->{'file_length'} = 0;
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231 | }
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232 | else
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233 | {
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234 | $self->{'fh'} = $self->{'client'}->open($path);
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235 | # for reading we need to know the file size so as to avoid Thrift throwing
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236 | # exceptions when we try to read past the end
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237 | my $file_stat = $self->{'client'}->stat($path);
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238 | $self->{'file_length'} = $file_stat->{length};
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239 | }
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240 | $self->{'mode'} = 'r'; # reading
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241 | }
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242 | return $self;
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243 | }
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244 | ## open() ##
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245 |
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246 |
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247 | ## @function binmode()
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248 | #
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249 | sub BINMODE
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250 | {
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251 | my $self = shift;
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252 | # Have we warned about BIN mode not being applicable?
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253 | if ($self->{'warnings'}->{'binmode'} != 1)
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254 | {
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255 | print STDERR "Notice! BIN mode not applicable in ThriftFS (all data base91 encoded)\n";
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256 | # we have now!
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257 | $self->{'warnings'}->{'binmode'} = 1;
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258 | }
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259 | }
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260 | ## BINMODE
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261 |
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262 |
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263 | ## @function eof()
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264 | #
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265 | sub EOF
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266 | {
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267 | my $self = shift;
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268 | return $self->{'eof'};
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269 | }
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270 | ## eof() ##
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271 |
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272 |
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273 | sub TELL
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274 | {
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275 | print STDERR "ThriftFH::TELL() - implement me!\n";
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276 | }
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277 |
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278 | sub SEEK
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279 | {
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280 | my $self = shift;
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281 | my ($offset, $whence) = @_;
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282 | print STDERR "ThriftFH::SEEK() - implement me!\n";
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283 | }
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284 |
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285 | sub DESTROY
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286 | {
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287 | my $self = shift;
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288 | if ($self->{'fh'} != 0)
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289 | {
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290 | $self->{'client'}->close($self->{'fh'});
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291 | $self->{'fh'} = 0;
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292 | }
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293 | }
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294 |
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295 | sub UNTIE
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296 | {
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297 | my $self = shift;
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298 | }
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299 |
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300 | 1;
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