DBM::Deep::Engine::File(3pm)

1DBM::Deep::Engine::FileU(s3e)r Contributed Perl DocumentaDtBiMo:n:Deep::Engine::File(3)
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NAME

6       DBM::Deep::Engine::File - engine for use with DBM::Deep::Storage::File
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PURPOSE

9       This is the engine for use with DBM::Deep::Storage::File.
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EXTERNAL METHODS

12   new()
13       This takes a set of args. These args are described in the documentation
14       for "new" in DBM::Deep.
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INTERNAL METHODS

17       The following methods are internal-use-only to DBM::Deep::Engine::File.
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19   read_txn_slots()
20       This takes no arguments.
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22       This will return an array with a 1 or 0 in each slot. Each spot
23       represents one available transaction. If the slot is 1, that
24       transaction is taken. If it is 0, the transaction is available.
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26   write_txn_slots( @slots )
27       This takes an array of 1's and 0's. This array represents the
28       transaction slots returned by "read_txn_slots()". In other words, the
29       following is true:
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31         @x = read_txn_slots( write_txn_slots( @x ) );
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33       (With the obviously missing object referents added back in.)
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35   get_running_txn_ids()
36       This takes no arguments.
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38       This will return an array of taken transaction IDs. This wraps
39       "read_txn_slots()".
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41   get_txn_staleness_counter( $trans_id )
42       This will return the staleness counter for the given transaction ID.
43       Please see "STALENESS" in DBM::Deep::Engine for more information.
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45   inc_txn_staleness_counter( $trans_id )
46       This will increment the staleness counter for the given transaction ID.
47       Please see "STALENESS" in DBM::Deep::Engine for more information.
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49   get_entries()
50       This takes no arguments.
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52       This returns a list of all the sectors that have been modified by this
53       transaction.
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55   add_entry( $trans_id, $location )
56       This takes a transaction ID and a file location and marks the sector at
57       that location as having been modified by the transaction identified by
58       $trans_id.
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60       This returns nothing.
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62       NOTE: Unlike all the other _entries() methods, there are several cases
63       where "$trans_id != $self->trans_id" for this method.
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65   reindex_entry( $old_loc, $new_loc )
66       This takes two locations (old and new, respectively). If a location
67       that has been modified by this transaction is subsequently reindexed
68       due to a bucketlist overflowing, then the entries hash needs to be made
69       aware of this change.
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71       This returns nothing.
72
73   clear_entries()
74       This takes no arguments. It will clear the entries list for the running
75       transaction.
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77       This returns nothing.
78
79   _write_file_header()
80       This writes the file header for a new file. This will write the various
81       settings that set how the file is interpreted.
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83   _read_file_header()
84       This reads the file header from an existing file. This will read the
85       various settings that set how the file is interpreted.
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87   _apply_digest( @stuff )
88       This will apply the digest method (default to Digest::MD5::md5) to the
89       arguments passed in and return the result.
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91   _add_free_blist_sector( $offset, $size )
92   _add_free_data_sector( $offset, $size )
93   _add_free_index_sector( $offset, $size )
94       These methods are all wrappers around _add_free_sector(), providing the
95       proper chain offset ($multiple) for the sector type.
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97   _add_free_sector( $multiple, $offset, $size )
98       _add_free_sector() takes the offset into the chains location, the
99       offset of the sector, and the size of that sector. It will mark the
100       sector as a free sector and put it into the list of sectors that are
101       free of this type for use later.
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103       This returns nothing.
104
105       NOTE: $size is unused?
106
107   _request_blist_sector( $size )
108   _request_data_sector( $size )
109   _request_index_sector( $size )
110       These methods are all wrappers around _request_sector(), providing the
111       proper chain offset ($multiple) for the sector type.
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113   _request_sector( $multiple $size )
114       This takes the offset into the chains location and the size of that
115       sector.
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117       This returns the object with the sector. If there is an available free
118       sector of that type, then it will be reused. If there isn't one, then a
119       new one will be allocated.
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121   ACCESSORS
122       The following are readonly attributes.
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124       ·   byte_size
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126       ·   hash_size
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128       ·   hash_chars
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130       ·   num_txns
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132       ·   max_buckets
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134       ·   blank_md5
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136       ·   data_sector_size
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138       ·   txn_bitfield_len
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140       The following are read/write attributes.
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142       ·   trans_id / set_trans_id( $new_id )
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144       ·   trans_loc / set_trans_loc( $new_loc )
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146       ·   chains_loc / set_chains_loc( $new_loc )
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148   _dump_file()
149       This method takes no arguments. It's used to print out a textual
150       representation of the DBM::Deep DB file. It assumes the file is not-
151       corrupted.
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155perl v5.28.1                      2019-02-02        DBM::Deep::Engine::File(3)