Commit | Line | Data |
460b1067 |
1 | package DBM::Deep::File; |
2 | |
3 | use 5.6.0; |
4 | |
5 | use strict; |
6 | use warnings; |
7 | |
8 | use Fcntl qw( :DEFAULT :flock :seek ); |
9 | |
10 | our $VERSION = '0.01'; |
11 | |
12 | sub new { |
13 | my $class = shift; |
14 | my ($args) = @_; |
15 | |
16 | my $self = bless { |
17 | autobless => undef, |
18 | autoflush => undef, |
19 | end => 0, |
20 | fh => undef, |
21 | file => undef, |
22 | file_offset => 0, |
23 | locking => undef, |
24 | locked => 0, |
25 | filter_store_key => undef, |
26 | filter_store_value => undef, |
27 | filter_fetch_key => undef, |
28 | filter_fetch_value => undef, |
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29 | |
20b7f047 |
30 | transaction_id => 0, |
31 | transaction_offset => 0, |
460b1067 |
32 | }, $class; |
33 | |
34 | # Grab the parameters we want to use |
35 | foreach my $param ( keys %$self ) { |
36 | next unless exists $args->{$param}; |
37 | $self->{$param} = $args->{$param}; |
38 | } |
39 | |
40 | if ( $self->{fh} && !$self->{file_offset} ) { |
41 | $self->{file_offset} = tell( $self->{fh} ); |
42 | } |
43 | |
44 | $self->open unless $self->{fh}; |
45 | |
46 | return $self; |
47 | } |
48 | |
49 | sub open { |
50 | my $self = shift; |
51 | |
52 | # Adding O_BINARY does remove the need for the binmode below. However, |
53 | # I'm not going to remove it because I don't have the Win32 chops to be |
54 | # absolutely certain everything will be ok. |
55 | my $flags = O_RDWR | O_CREAT | O_BINARY; |
56 | |
57 | my $fh; |
58 | sysopen( $fh, $self->{file}, $flags ) |
59 | or die "DBM::Deep: Cannot sysopen file '$self->{file}': $!\n"; |
60 | $self->{fh} = $fh; |
61 | |
62 | # Even though we use O_BINARY, better be safe than sorry. |
63 | binmode $fh; |
64 | |
65 | if ($self->{autoflush}) { |
66 | my $old = select $fh; |
67 | $|=1; |
68 | select $old; |
69 | } |
70 | |
71 | return 1; |
72 | } |
73 | |
74 | sub close { |
75 | my $self = shift; |
76 | |
77 | if ( $self->{fh} ) { |
78 | close $self->{fh}; |
79 | $self->{fh} = undef; |
80 | } |
81 | |
82 | return 1; |
83 | } |
84 | |
85 | sub DESTROY { |
86 | my $self = shift; |
87 | return unless $self; |
88 | |
89 | $self->close; |
90 | |
91 | return; |
92 | } |
93 | |
15ba72cc |
94 | ## |
95 | # If db locking is set, flock() the db file. If called multiple |
96 | # times before unlock(), then the same number of unlocks() must |
97 | # be called before the lock is released. |
98 | ## |
99 | sub lock { |
100 | my $self = shift; |
101 | my ($obj, $type) = @_; |
102 | $type = LOCK_EX unless defined $type; |
103 | |
104 | if (!defined($self->{fh})) { return; } |
105 | |
106 | if ($self->{locking}) { |
107 | if (!$self->{locked}) { |
108 | flock($self->{fh}, $type); |
109 | |
110 | # refresh end counter in case file has changed size |
111 | my @stats = stat($self->{fh}); |
112 | $self->{end} = $stats[7]; |
113 | |
114 | # double-check file inode, in case another process |
115 | # has optimize()d our file while we were waiting. |
116 | if ($stats[1] != $self->{inode}) { |
117 | $self->close; |
118 | $self->open; |
119 | |
120 | #XXX This needs work |
121 | $obj->{engine}->setup_fh( $obj ); |
122 | |
123 | flock($self->{fh}, $type); # re-lock |
124 | |
125 | # This may not be necessary after re-opening |
126 | $self->{end} = (stat($self->{fh}))[7]; # re-end |
127 | } |
128 | } |
129 | $self->{locked}++; |
130 | |
131 | return 1; |
132 | } |
133 | |
134 | return; |
135 | } |
136 | |
137 | ## |
138 | # If db locking is set, unlock the db file. See note in lock() |
139 | # regarding calling lock() multiple times. |
140 | ## |
141 | sub unlock { |
142 | my $self = shift; |
143 | |
144 | if (!defined($self->{fh})) { return; } |
145 | |
146 | if ($self->{locking} && $self->{locked} > 0) { |
147 | $self->{locked}--; |
148 | if (!$self->{locked}) { flock($self->{fh}, LOCK_UN); } |
149 | |
150 | return 1; |
151 | } |
152 | |
153 | return; |
154 | } |
155 | |
156 | sub set_transaction_offset { |
157 | my $self = shift; |
158 | $self->{transaction_offset} = shift; |
159 | } |
160 | |
28394a1a |
161 | sub begin_transaction { |
162 | my $self = shift; |
163 | |
15ba72cc |
164 | my $fh = $self->{fh}; |
165 | |
20b7f047 |
166 | $self->lock; |
167 | |
168 | seek( $fh, $self->{transaction_offset}, SEEK_SET ); |
169 | my $buffer; |
170 | read( $fh, $buffer, 4 ); |
171 | $buffer = unpack( 'N', $buffer ); |
172 | |
173 | for ( 1 .. 32 ) { |
174 | next if $buffer & (1 << ($_ - 1)); |
175 | $self->{transaction_id} = $_; |
c9b6d0d8 |
176 | $buffer |= (1 << $_-1 ); |
20b7f047 |
177 | last; |
178 | } |
179 | |
15ba72cc |
180 | seek( $fh, $self->{transaction_offset}, SEEK_SET ); |
20b7f047 |
181 | print( $fh pack( 'N', $buffer ) ); |
15ba72cc |
182 | |
20b7f047 |
183 | $self->unlock; |
184 | |
185 | return $self->{transaction_id}; |
28394a1a |
186 | } |
187 | |
188 | sub end_transaction { |
189 | my $self = shift; |
190 | |
20b7f047 |
191 | my $fh = $self->{fh}; |
192 | |
193 | $self->lock; |
194 | |
195 | seek( $fh, $self->{transaction_offset}, SEEK_SET ); |
196 | my $buffer; |
197 | read( $fh, $buffer, 4 ); |
198 | $buffer = unpack( 'N', $buffer ); |
199 | |
200 | # Unset $self->{transaction_id} bit |
201 | |
202 | seek( $fh, $self->{transaction_offset}, SEEK_SET ); |
203 | print( $fh pack( 'N', $buffer ) ); |
204 | |
205 | $self->unlock; |
15ba72cc |
206 | |
28394a1a |
207 | $self->{transaction_id} = 0; |
208 | } |
209 | |
20b7f047 |
210 | sub current_transactions { |
28394a1a |
211 | my $self = shift; |
212 | |
20b7f047 |
213 | my $fh = $self->{fh}; |
214 | |
215 | $self->lock; |
216 | |
217 | seek( $fh, $self->{transaction_offset}, SEEK_SET ); |
218 | my $buffer; |
219 | read( $fh, $buffer, 4 ); |
220 | $buffer = unpack( 'N', $buffer ); |
221 | |
222 | $self->unlock; |
223 | |
224 | my @transactions; |
225 | for ( 1 .. 32 ) { |
226 | if ( $buffer & (1 << ($_ - 1)) ) { |
227 | push @transactions, $_; |
228 | } |
229 | } |
230 | |
c9b6d0d8 |
231 | return grep { $_ != $self->{transaction_id} } @transactions; |
28394a1a |
232 | } |
233 | |
20b7f047 |
234 | sub transaction_id { return $_[0]->{transaction_id} } |
235 | |
28394a1a |
236 | #sub commit { |
237 | #} |
238 | |
460b1067 |
239 | 1; |
240 | __END__ |
241 | |