root/main/trunk/greenstone2/perllib/DBDrivers/BaseDBDriver.pm @ 30370

Revision 30370, 14.4 KB (checked in by jmt12, 5 years ago)

Reverting these back to the older but better supported ISA approach to declaring inheritance. Not even sure why I used the new parent mechanism (aside from possibly copying from tutorial)... can I still blame baby brain after 10 months?

Line 
1###############################################################################
2#
3# BaseDBDriver.pm -- base class for all the database drivers
4# A component of the Greenstone digital library software from the New Zealand
5# Digital Library Project at the University of Waikato, New Zealand.
6#
7# Copyright (c) 2015 New Zealand Digital Library Project
8#
9# This program is free software; you can redistribute it and/or modify it under
10# the terms of the GNU General Public License as published by the Free Software
11# Foundation; either version 2 of the License, or (at your option) any later
12# version.
13#
14# This program is distributed in the hope that it will be useful, but WITHOUT
15# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
16# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
17# more details.
18#
19# You should have received a copy of the GNU General Public License along with
20# this program; if not, write to the Free Software Foundation, Inc., 675 Mass
21# Ave, Cambridge, MA 02139, USA.
22#
23###############################################################################
24
25package DBDrivers::BaseDBDriver;
26
27# Pragma
28use strict;
29no strict 'subs';
30no strict 'refs'; # allow filehandles to be variables and viceversa
31
32# Libaries
33use Time::HiRes qw( gettimeofday );
34use gsprintf 'gsprintf';
35
36
37## @function constructor
38#
39sub new
40{
41    my $class = shift(@_);
42    my $debug = shift(@_);
43    my $self = {};
44    # Debug messages for this driver
45    $self->{'debug'} = $debug; # 1 to enable
46    # We'll use this in places other than 70HyphenFormat
47    $self->{'70hyphen'} = '-' x 70;
48    # Keep track of all opened file handles, but only for drivers that support
49    # persistent connections
50    $self->{'handle_pool'} = {};
51    # Default file extension - in this case it is an error to create a DB from
52    # BaseDBDriver
53    $self->{'default_file_extension'} = 'err';
54    # Support
55    $self->{'supports_datestamp'} = 0;
56    $self->{'supports_merge'} = 0;
57    $self->{'supports_persistentconnection'} = 0;
58    $self->{'supports_rss'} = 0;
59    $self->{'supports_set'} = 0;
60    $self->{'write_only'} = 0; # Some drivers are one way - i.e. STDOUTXML
61    bless($self, $class);
62    return $self;
63}
64## new(void) => BaseDBDriver ##
65
66
67## @function DESTROY
68#
69# Built-in destructor block that, unlike END, gets passed a reference to self.
70# Responsible for properly closing any open database handles.
71#
72sub DESTROY
73{
74    my $self = shift(@_);
75    # Close all remaining filehandles
76    foreach my $infodb_file_path (keys(%{$self->{'handle_pool'}})) {
77    my $infodb_handle = $self->{'handle_pool'}->{$infodb_file_path};
78    # By passing the filepath as the second argument we instruct the driver
79    # that we actually want to close the connection by passing a non-zero
80    # value, but we sneakily optimize things a little as the close method
81    # can now check to see if it's been provided a file_path rather than
82    # having to search the handle pool for it. The file_path is needed to
83    # remove the closed handle from the pool anyway.
84    $self->close_infodb_write_handle($infodb_handle, $infodb_file_path);
85    }
86}
87## DESTROY(void) => void ##
88
89
90###############################################################################
91## Protected Functions
92###############################################################################
93
94
95## @function debugPrint(string) => void
96#
97sub debugPrint
98{
99    my $self = shift(@_);
100    my $message = shift(@_);
101    if ($self->{'debug'}) {
102    my ($seconds, $microseconds) = gettimeofday();
103    print STDERR '[DEBUG:' . $seconds . '.' . $microseconds . '] ' . (caller 1)[3] . '() ' . $message . "\n";
104    }
105}
106## debugPrint(string) => void ##
107
108
109## @function debugPrintFunctionHeader(*) => void
110#
111sub debugPrintFunctionHeader
112{
113    my $self = shift(@_);
114    if ($self->{'debug'}) {
115    my @arguments;
116    foreach my $argument (@_) {
117        if ($argument !~ /^-?\d+(\.?\d+)?$/) {
118        push(@arguments, '"' . $argument . '"');
119        }
120        else {
121        push(@arguments, $argument);
122        }
123    }
124    my $message = '(' . join(', ', @arguments) . ')';
125    # Would love to just call debugPrint() here, but then caller would be wrong
126    my ($seconds, $microseconds) = gettimeofday();
127    print STDERR '[DEBUG:' . $seconds . '.' . $microseconds . '] ' . (caller 1)[3] . $message . "\n";
128    }
129}
130## debugPrintFunctionHeader(*) => void
131
132
133## @function errorPrint(string, integer) => void
134#
135sub errorPrint
136{
137    my $self = shift(@_);
138    my $message = shift(@_);
139    my $is_fatal = shift(@_);
140    print STDERR 'Error in ' . (caller 1)[3] . '! ' . $message . "\n";
141    if ($is_fatal) {
142    exit();
143    }
144}
145## errorPrint(string, integer) => void ##
146
147
148## @function registerConnectionIfPersistent(filehandle, string, string) => void
149#
150sub registerConnectionIfPersistent
151{
152    my $self = shift(@_);
153    my $conn = shift(@_);
154    my $path = shift(@_);
155    my $append = shift(@_);
156    if ($self->{'supports_persistentconnection'}) {
157    $self->debugPrintFunctionHeader($conn, $path, $append);
158    my $fhid = $path;
159    if (defined $append && $append eq '-append') {
160        $fhid .= ' [APPEND]';
161    }
162    $self->debugPrint('Registering connection: "' . $fhid . '"');
163    $self->{'handle_pool'}->{$fhid} = $conn;
164    }
165    return;
166}
167## registerConnectionIfPersistent(filehandle, string, string) => void ##
168
169
170## @function removeConnectionIfPersistent(filehandle, string) => integer
171#
172sub removeConnectionIfPersistent
173{
174    my $self = shift(@_);
175    my $handle = shift(@_);
176    my $force_close = shift(@_);
177    my $continue_close = 1;
178    if ($self->{'supports_persistentconnection'}) {
179    $self->debugPrintFunctionHeader($handle, $force_close);
180    if (defined($force_close)) {
181        # We'll need the file path so we can locate and remove the entry
182        # in the handle pool (plus possibly the [APPEND] suffix for those
183        # connections in opened in append mode)
184        my $fhid = undef;
185        # Sometimes we can cheat, as the force_close variable will have the
186        # file_path in it thanks to the DESTROY block above. Doing a regex
187        # on force_close will treat it like a string no matter what it was,
188        # and we can search for the appropriate file extension that should
189        # be there for valid paths.
190        my $pattern = '\.' . $self->{'default_file_extension'} . '(\s\[APPEND\])?$';
191        if ($force_close =~ /$pattern/) {
192        $fhid = $force_close;
193        }
194        # If we can't cheat then we are stuck finding which connection in
195        # the handle_pool we are about to close. Need to compare objects
196        # using refaddr()
197        else {
198        foreach my $possible_fhid (keys %{$self->{'handle_pool'}}) {
199            my $possible_handle = $self->{'handle_pool'}->{$possible_fhid};
200            if (ref($handle) && ref($possible_handle) && refaddr($handle) == refaddr($possible_handle)) {
201            $fhid = $possible_fhid;
202            last;
203            }
204        }
205        }
206        # If we found the fhid we can proceed to close the connection
207        if (defined($fhid)) {
208        $self->debugPrint('Closing persistent connection: ' . $fhid);
209        delete($self->{'handle_pool'}->{$fhid});
210        $continue_close = 1;
211        }
212        else {
213        print STDERR "Warning! About to close persistent database handle, but couldn't locate in open handle pool.\n";
214        }
215    }
216    # Persistent connection don't close *unless* force close is set
217    else {
218        $continue_close = 0;
219    }
220    }
221    return $continue_close;
222}
223## removeConnectionIfPersistent(filehandle, string) => integer ##
224
225
226##
227#
228sub retrieveConnectionIfPersistent
229{
230    my $self = shift(@_);
231    my $path = shift(@_);
232    my $append = shift(@_); # -append support
233    my $conn; # This should be populated
234    if ($self->{'supports_persistentconnection'}) {
235    $self->debugPrintFunctionHeader($path, $append);
236    my $fhid = $path;
237    # special case: if the append mode has changed for a persistent
238    # connection, we need to close the old connection first or things
239    # will get wiggy.
240    if (defined $append && $append eq '-append') {
241        # see if there is a non-append mode connection already open
242        if (defined $self->{'handle_pool'}->{$path}) {
243        $self->debugPrint("Append mode added - closing existing non-append mode connection");
244        my $old_conn = $self->{'handle_pool'}->{$path};
245        $self->close_infodb_write_handle($old_conn, $path);
246        }
247        # Append -append so we know what happened.
248        $fhid .= ' [APPEND]';
249    }
250    else {
251        my $fhid_append = $path . ' [APPEND]';
252        if (defined $self->{'handle_pool'}->{$fhid_append}) {
253        $self->debugPrint("Append mode removed - closing existing append mode connection");
254        my $old_conn = $self->{'handle_pool'}->{$fhid_append};
255        $self->close_infodb_write_handle($old_conn, $fhid_append);
256        }
257    }
258    if (defined $self->{'handle_pool'}->{$fhid}) {
259        $self->debugPrint('Retrieving existing connection: ' . $fhid);
260        $conn = $self->{'handle_pool'}->{$fhid};
261    }
262    }
263    return $conn;
264}
265## ##
266
267
268
269
270
271
272
273###############################################################################
274## Public Functions
275###############################################################################
276
277
278## @function convert_infodb_hash_to_string(hashmap) => string
279#
280sub convert_infodb_hash_to_string
281{
282    my $self = shift(@_);
283    my $infodb_map = shift(@_);
284    my $infodb_entry_value = "";
285    foreach my $infodb_value_key (keys(%$infodb_map)) {
286        foreach my $infodb_value (@{$infodb_map->{$infodb_value_key}}) {
287            $infodb_entry_value .= "<$infodb_value_key>" . $infodb_value . "\n";
288        }
289    }
290    return $infodb_entry_value;
291}
292## convert_infodb_hash_to_string(hashmap) => string ##
293
294
295## @function convert_infodb_string_to_hash(string) => hashmap
296#
297sub convert_infodb_string_to_hash
298{
299    my $self = shift(@_);
300    my $infodb_entry_value = shift(@_);
301    my $infodb_map = ();
302
303    if (!defined $infodb_entry_value) {
304    print STDERR "Warning: No value to convert into a infodb hashtable\n";
305    }
306    else {
307        while ($infodb_entry_value =~ /^<(.*?)>(.*)$/mg) {
308            my $infodb_value_key = $1;
309            my $infodb_value = $2;
310
311            if (!defined($infodb_map->{$infodb_value_key})) {
312                $infodb_map->{$infodb_value_key} = [ $infodb_value ];
313            }
314            else {
315                push(@{$infodb_map->{$infodb_value_key}}, $infodb_value);
316            }
317    }
318    }
319
320    return $infodb_map;
321}
322## convert_infodb_string_to_hash(string) => hashmap ##
323
324
325## @function get_infodb_file_path(string, string) => string
326#
327sub get_infodb_file_path
328{
329    my $self = shift(@_);
330    my $collection_name = shift(@_);
331    my $infodb_directory_path = shift(@_);
332    my $infodb_file_name = &util::get_dirsep_tail($collection_name) . '.' . $self->{'default_file_extension'};
333    my $infodb_file_path = &FileUtils::filenameConcatenate($infodb_directory_path, $infodb_file_name);
334    # Correct the path separators to work in Cygwin
335    if ($^O eq "cygwin") {
336    $infodb_file_path = `cygpath -w "$infodb_file_path"`;
337    chomp($infodb_file_path);
338    $infodb_file_path =~ s%\\%\\\\%g;
339    }
340    return $infodb_file_path;
341}
342## get_infodb_file_path(string, string) => string ##
343
344
345## @function supportsDatestamp(void) => integer
346#
347sub supportsDatestamp
348{
349    my $self = shift(@_);
350    return $self->{'supports_datestamp'};
351}
352## supportsDatestamp(void) => integer ##
353
354
355## @function supportsMerge(void) => boolean
356#
357sub supportsMerge
358{
359    my $self = shift(@_);
360    return $self->{'supports_merge'};
361}
362## supportsMerge(void) => integer ##
363
364
365## @function supportsPersistentConnection(void) => integer
366#
367sub supportsPersistentConnection
368{
369    my $self = shift(@_);
370    return $self->{'supports_persistentconnection'};
371}
372## supportsPersistentConnection(void) => integer ##
373
374
375## @function supportsRSS(void) => integer
376#
377sub supportsRSS
378{
379    my $self = shift(@_);
380    return $self->{'supports_rss'};
381}
382## supportsRSS(void) => integer ##
383
384
385## @function supportsSet(void) => integer
386#
387#  Not all drivers support the notion of set
388#
389sub supportsSet
390{
391    my $self = shift(@_);
392    return $self->{'supports_set'};
393}
394## supportsSet(void) => integer ##
395
396
397sub writeOnly
398{
399    my $self = shift(@_);
400    return $self->{'write_only'};
401}
402## writeOnly() ##
403
404###############################################################################
405## Virtual Functions
406###############################################################################
407
408
409## @function close_infodb_write_handle(*) => void
410#
411sub close_infodb_write_handle
412{
413    my $self = shift(@_);
414    gsprintf(STDERR, (caller(0))[3] . " {common.must_be_implemented}\n");
415    die("\n");
416}
417## close_infodb_write_handle(*) => void ##
418
419
420## @function delete_infodb_entry(*) => void
421#
422sub delete_infodb_entry
423{
424    my $self = shift(@_);
425    gsprintf(STDERR, (caller(0))[3] . " {common.must_be_implemented}\n");
426    die("\n");
427}
428## delete_infodb_entry(*) => void ##
429
430
431## @function mergeDatabases(*) => void
432#
433sub mergeDatabases
434{
435    my $self = shift(@_);
436    gsprintf(STDERR, (caller(0))[3] . " {common.must_be_implemented}\n");
437    die("\n");
438}
439## mergeDatabases(*) => void ##
440
441
442## @function open_infodb_write_handle(*) => void
443#
444sub open_infodb_write_handle
445{
446    my $self = shift(@_);
447    gsprintf(STDERR, (caller(0))[3] . " {common.must_be_implemented}\n");
448    die("\n");
449}
450## open_infodb_write_handle(*) => void ##
451
452
453## @function set_infodb_entry(*) => void
454#
455sub set_infodb_entry
456{
457    my $self = shift(@_);
458    gsprintf(STDERR, (caller(0))[3] . " {common.must_be_implemented}\n");
459    die("\n");
460}
461## set_infodb_entry(*) => void ##
462
463
464## @function read_infodb_entry(*) => void
465#
466sub read_infodb_entry
467{
468    my $self = shift(@_);
469    gsprintf(STDERR, (caller(0))[3] . " {common.must_be_implemented}\n");
470    die("\n");
471}
472## read_infodb_entry(*) => void ##
473
474
475## @function read_infodb_rawentry(*) => string
476#
477sub read_infodb_rawentry
478{
479    my $self = shift(@_);
480    gsprintf(STDERR, (caller(0))[3] . " {common.must_be_implemented}\n");
481    die("\n");
482}
483## read_infodb_rawentry(*) => string ##
484
485
486## @function read_infodb_file(*) => void
487#
488sub read_infodb_file
489{
490    my $self = shift(@_);
491    gsprintf(STDERR, (caller(0))[3] . " {common.must_be_implemented}\n");
492    die("\n");
493}
494## read_infodb_file(*) => void ##
495
496
497## @function read_infodb_keys(*) => void
498#
499sub read_infodb_keys
500{
501    my $self = shift(@_);
502    gsprintf(STDERR, (caller(0))[3] . " {common.must_be_implemented}\n");
503    die("\n");
504}
505## read_infodb_keys(*) => void ##
506
507
508## @function write_infodb_entry(*) => void
509#
510sub write_infodb_entry
511{
512    my $self = shift(@_);
513    gsprintf(STDERR, (caller(0))[3] . " {common.must_be_implemented}\n");
514    die("\n");
515}
516## write_infodb_entry(*) => void ##
517
518
519## @function write_infodb_rawentry(*) => void
520#
521sub write_infodb_rawentry
522{
523    my $self = shift(@_);
524    gsprintf(STDERR, (caller(0))[3] . " {common.must_be_implemented}\n");
525    die("\n");
526}
527## write_infodb_rawentry(*) => void ##
528
529
5301;
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