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1 | package DBIx::Class::Storage::TxnScopeGuard; |
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2 | |
3 | use strict; |
4 | use warnings; |
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5 | use Try::Tiny; |
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6 | use Scalar::Util qw/weaken blessed/; |
7 | use DBIx::Class::Exception; |
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8 | use DBIx::Class::Carp; |
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9 | |
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10 | # temporary until we fix the $@ issue in core |
11 | # we also need a real appendable, stackable exception object |
12 | # (coming soon) |
13 | BEGIN { |
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14 | if ($] >= 5.013001 and $] <= 5.013007) { |
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15 | *IS_BROKEN_PERL = sub () { 1 }; |
16 | } |
17 | else { |
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18 | *IS_BROKEN_PERL = sub () { 0 }; |
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19 | } |
20 | } |
21 | |
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22 | use namespace::clean; |
23 | |
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24 | my ($guards_count, $compat_handler, $foreign_handler); |
25 | |
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26 | sub new { |
27 | my ($class, $storage) = @_; |
28 | |
29 | $storage->txn_begin; |
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30 | my $guard = bless [ 0, $storage, $storage->_dbh ], ref $class || $class; |
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31 | |
32 | |
33 | # install a callback carefully |
34 | if (IS_BROKEN_PERL and !$guards_count) { |
35 | |
36 | # if the thrown exception is a plain string, wrap it in our |
37 | # own exception class |
38 | # this is actually a pretty cool idea, may very well keep it |
39 | # after perl is fixed |
40 | $compat_handler ||= bless( |
41 | sub { |
42 | $@ = (blessed($_[0]) or ref($_[0])) |
43 | ? $_[0] |
44 | : bless ( { msg => $_[0] }, 'DBIx::Class::Exception') |
45 | ; |
46 | die; |
47 | }, |
48 | '__TxnScopeGuard__FIXUP__', |
49 | ); |
50 | |
51 | if ($foreign_handler = $SIG{__DIE__}) { |
52 | $SIG{__DIE__} = bless ( |
53 | sub { |
54 | # we trust the foreign handler to do whatever it wants, all we do is set $@ |
55 | eval { $compat_handler->(@_) }; |
56 | $foreign_handler->(@_); |
57 | }, |
58 | '__TxnScopeGuard__FIXUP__', |
59 | ); |
60 | } |
61 | else { |
62 | $SIG{__DIE__} = $compat_handler; |
63 | } |
64 | } |
65 | |
66 | $guards_count++; |
67 | |
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68 | weaken ($guard->[2]); |
69 | $guard; |
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70 | } |
71 | |
72 | sub commit { |
73 | my $self = shift; |
74 | |
75 | $self->[1]->txn_commit; |
76 | $self->[0] = 1; |
77 | } |
78 | |
79 | sub DESTROY { |
80 | my ($dismiss, $storage) = @{$_[0]}; |
81 | |
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82 | $guards_count--; |
83 | |
84 | # don't touch unless it's ours, and there are no more of us left |
85 | if ( |
86 | IS_BROKEN_PERL |
87 | and |
88 | !$guards_count |
89 | ) { |
90 | |
91 | if (ref $SIG{__DIE__} eq '__TxnScopeGuard__FIXUP__') { |
92 | # restore what we saved |
93 | if ($foreign_handler) { |
94 | $SIG{__DIE__} = $foreign_handler; |
95 | } |
96 | else { |
97 | delete $SIG{__DIE__}; |
98 | } |
99 | } |
100 | |
101 | # make sure we do not leak the foreign one in case it exists |
102 | undef $foreign_handler; |
103 | } |
104 | |
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105 | return if $dismiss; |
106 | |
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107 | # if our dbh is not ours anymore, the weakref will go undef |
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108 | $storage->_verify_pid; |
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109 | return unless $_[0]->[2]; |
110 | |
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111 | my $exception = $@; |
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112 | |
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113 | { |
114 | local $@; |
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115 | |
116 | carp 'A DBIx::Class::Storage::TxnScopeGuard went out of scope without explicit commit or error. Rolling back.' |
117 | unless $exception; |
118 | |
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119 | my $rollback_exception; |
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120 | # do minimal connectivity check due to weird shit like |
121 | # https://rt.cpan.org/Public/Bug/Display.html?id=62370 |
122 | try { $storage->_seems_connected && $storage->txn_rollback } |
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123 | catch { $rollback_exception = shift }; |
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124 | |
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125 | if (defined $rollback_exception && $rollback_exception !~ /DBIx::Class::Storage::NESTED_ROLLBACK_EXCEPTION/) { |
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126 | # append our text - THIS IS A TEMPORARY FIXUP! |
127 | # a real stackable exception object is in the works |
128 | if (ref $exception eq 'DBIx::Class::Exception') { |
129 | $exception->{msg} = "Transaction aborted: $exception->{msg} " |
130 | ."Rollback failed: ${rollback_exception}"; |
131 | } |
132 | elsif ($exception) { |
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133 | $exception = "Transaction aborted: ${exception} " |
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134 | ."Rollback failed: ${rollback_exception}"; |
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135 | } |
136 | else { |
137 | carp (join ' ', |
138 | "********************* ROLLBACK FAILED!!! ********************", |
139 | "\nA rollback operation failed after the guard went out of scope.", |
140 | 'This is potentially a disastrous situation, check your data for', |
141 | "consistency: $rollback_exception" |
142 | ); |
143 | } |
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144 | } |
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145 | } |
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146 | |
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147 | $@ = $exception unless IS_BROKEN_PERL; |
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148 | } |
149 | |
150 | 1; |
151 | |
152 | __END__ |
153 | |
154 | =head1 NAME |
155 | |
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156 | DBIx::Class::Storage::TxnScopeGuard - Scope-based transaction handling |
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157 | |
158 | =head1 SYNOPSIS |
159 | |
160 | sub foo { |
161 | my ($self, $schema) = @_; |
162 | |
163 | my $guard = $schema->txn_scope_guard; |
164 | |
165 | # Multiple database operations here |
166 | |
167 | $guard->commit; |
168 | } |
169 | |
170 | =head1 DESCRIPTION |
171 | |
172 | An object that behaves much like L<Scope::Guard>, but hardcoded to do the |
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173 | right thing with transactions in DBIx::Class. |
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174 | |
175 | =head1 METHODS |
176 | |
177 | =head2 new |
178 | |
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179 | Creating an instance of this class will start a new transaction (by |
180 | implicitly calling L<DBIx::Class::Storage/txn_begin>. Expects a |
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181 | L<DBIx::Class::Storage> object as its only argument. |
182 | |
183 | =head2 commit |
184 | |
185 | Commit the transaction, and stop guarding the scope. If this method is not |
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186 | called and this object goes out of scope (e.g. an exception is thrown) then |
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187 | the transaction is rolled back, via L<DBIx::Class::Storage/txn_rollback> |
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188 | |
189 | =cut |
190 | |
191 | =head1 SEE ALSO |
192 | |
193 | L<DBIx::Class::Schema/txn_scope_guard>. |
194 | |
195 | =head1 AUTHOR |
196 | |
197 | Ash Berlin, 2008. |
198 | |
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199 | Inspired by L<Scope::Guard> by chocolateboy. |
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200 | |
201 | This module is free software. It may be used, redistributed and/or modified |
202 | under the same terms as Perl itself. |
203 | |
204 | =cut |