X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FDBIx%2FClass%2FStorage.pm;h=c9f4383469ff77cce03a4e24b3b45dd835cd931d;hb=07f31d19981c5c9e1754f4a63da2fe461baa048d;hp=973f31b63fa38b4b5e82f73ea62b38bef67e762d;hpb=4012acd8f58480ab7729933dc9078c5f2a6feef2;p=dbsrgits%2FDBIx-Class.git

diff --git a/lib/DBIx/Class/Storage.pm b/lib/DBIx/Class/Storage.pm
index 973f31b..c9f4383 100644
--- a/lib/DBIx/Class/Storage.pm
+++ b/lib/DBIx/Class/Storage.pm
@@ -3,6 +3,21 @@ package DBIx::Class::Storage;
 use strict;
 use warnings;
 
+use base qw/DBIx::Class/;
+use mro 'c3';
+
+use DBIx::Class::Exception;
+use Scalar::Util();
+use IO::File;
+use DBIx::Class::Storage::TxnScopeGuard;
+
+__PACKAGE__->mk_group_accessors('simple' => qw/debug debugobj schema/);
+__PACKAGE__->mk_group_accessors('inherited' => 'cursor_class');
+
+__PACKAGE__->cursor_class('DBIx::Class::Cursor');
+
+sub cursor { shift->cursor_class(@_); }
+
 package # Hide from PAUSE
     DBIx::Class::Storage::NESTED_ROLLBACK_EXCEPTION;
 
@@ -18,29 +33,100 @@ sub new {
 
 package DBIx::Class::Storage;
 
-sub new { die "Virtual method!" }
-sub set_schema { die "Virtual method!" }
-sub debug { die "Virtual method!" }
-sub debugcb { die "Virtual method!" }
-sub debugfh { die "Virtual method!" }
-sub debugobj { die "Virtual method!" }
-sub cursor { die "Virtual method!" }
-sub disconnect { die "Virtual method!" }
+=head1 NAME
+
+DBIx::Class::Storage - Generic Storage Handler
+
+=head1 DESCRIPTION
+
+A base implementation of common Storage methods.  For specific
+information about L<DBI>-based storage, see L<DBIx::Class::Storage::DBI>.
+
+=head1 METHODS
+
+=head2 new
+
+Arguments: $schema
+
+Instantiates the Storage object.
+
+=cut
+
+sub new {
+  my ($self, $schema) = @_;
+
+  $self = ref $self if ref $self;
+
+  my $new = {};
+  bless $new, $self;
+
+  $new->set_schema($schema);
+  $new->debugobj(new DBIx::Class::Storage::Statistics());
+
+  #my $fh;
+
+  my $debug_env = $ENV{DBIX_CLASS_STORAGE_DBI_DEBUG}
+                  || $ENV{DBIC_TRACE};
+
+  $new->debug(1) if $debug_env;
+
+  $new;
+}
+
+=head2 set_schema
+
+Used to reset the schema class or object which owns this
+storage object, such as during L<DBIx::Class::Schema/clone>.
+
+=cut
+
+sub set_schema {
+  my ($self, $schema) = @_;
+  $self->schema($schema);
+  Scalar::Util::weaken($self->{schema}) if ref $self->{schema};
+}
+
+=head2 connected
+
+Returns true if we have an open storage connection, false
+if it is not (yet) open.
+
+=cut
+
 sub connected { die "Virtual method!" }
+
+=head2 disconnect
+
+Closes any open storage connection unconditionally.
+
+=cut
+
+sub disconnect { die "Virtual method!" }
+
+=head2 ensure_connected
+
+Initiate a connection to the storage if one isn't already open.
+
+=cut
+
 sub ensure_connected { die "Virtual method!" }
-sub on_connect_do { die "Virtual method!" }
-sub connect_info { die "Virtual method!" }
-sub sql_maker { die "Virtual method!" }
-sub txn_begin { die "Virtual method!" }
-sub txn_commit { die "Virtual method!" }
-sub txn_rollback { die "Virtual method!" }
-sub insert { die "Virtual method!" }
-sub update { die "Virtual method!" }
-sub delete { die "Virtual method!" }
-sub select { die "Virtual method!" }
-sub select_single { die "Virtual method!" }
-sub columns_info_for { die "Virtual method!" }
-sub throw_exception { die "Virtual method!" }
+
+=head2 throw_exception
+
+Throws an exception - croaks.
+
+=cut
+
+sub throw_exception {
+  my $self = shift;
+
+  if ($self->schema) {
+    $self->schema->throw_exception(@_);
+  }
+  else {
+    DBIx::Class::Exception->throw(@_);
+  }
+}
 
 =head2 txn_do
 
@@ -87,6 +173,15 @@ In a nested transaction (calling txn_do() from within a txn_do() coderef) only
 the outermost transaction will issue a L</txn_commit>, and txn_do() can be
 called in void, scalar and list context and it will behave as expected.
 
+Please note that all of the code in your coderef, including non-DBIx::Class
+code, is part of a transaction.  This transaction may fail out halfway, or
+it may get partially double-executed (in the case that our DB connection
+failed halfway through the transaction, in which case we reconnect and
+restart the txn).  Therefore it is best that any side-effects in your coderef
+are idempotent (that is, can be re-executed multiple times and get the
+same result), and that you check up on your side-effects in the case of
+transaction failure.
+
 =cut
 
 sub txn_do {
@@ -143,4 +238,274 @@ sub txn_do {
   return $wantarray ? @return_values : $return_value;
 }
 
+=head2 txn_begin
+
+Starts a transaction.
+
+See the preferred L</txn_do> method, which allows for
+an entire code block to be executed transactionally.
+
+=cut
+
+sub txn_begin { die "Virtual method!" }
+
+=head2 txn_commit
+
+Issues a commit of the current transaction.
+
+It does I<not> perform an actual storage commit unless there's a DBIx::Class
+transaction currently in effect (i.e. you called L</txn_begin>).
+
+=cut
+
+sub txn_commit { die "Virtual method!" }
+
+=head2 txn_rollback
+
+Issues a rollback of the current transaction. A nested rollback will
+throw a L<DBIx::Class::Storage::NESTED_ROLLBACK_EXCEPTION> exception,
+which allows the rollback to propagate to the outermost transaction.
+
+=cut
+
+sub txn_rollback { die "Virtual method!" }
+
+=head2 svp_begin
+
+Arguments: $savepoint_name?
+
+Created a new savepoint using the name provided as argument. If no name
+is provided, a random name will be used.
+
+=cut
+
+sub svp_begin { die "Virtual method!" }
+
+=head2 svp_release
+
+Arguments: $savepoint_name?
+
+Release the savepoint provided as argument. If none is provided,
+release the savepoint created most recently. This will implicitly
+release all savepoints created after the one explicitly released as well.
+
+=cut
+
+sub svp_release { die "Virtual method!" }
+
+=head2 svp_rollback
+
+Arguments: $savepoint_name?
+
+Rollback to the savepoint provided as argument. If none is provided,
+rollback to the savepoint created most recently. This will implicitly
+release all savepoints created after the savepoint we rollback to.
+
+=cut
+
+sub svp_rollback { die "Virtual method!" }
+
+=for comment
+
+=head2 txn_scope_guard
+
+An alternative way of transaction handling based on
+L<DBIx::Class::Storage::TxnScopeGuard>:
+
+ my $txn_guard = $storage->txn_scope_guard;
+
+ $row->col1("val1");
+ $row->update;
+
+ $txn_guard->commit;
+
+If an exception occurs, or the guard object otherwise leaves the scope
+before C<< $txn_guard->commit >> is called, the transaction will be rolled
+back by an explicit L</txn_rollback> call. In essence this is akin to
+using a L</txn_begin>/L</txn_commit> pair, without having to worry
+about calling L</txn_rollback> at the right places. Note that since there
+is no defined code closure, there will be no retries and other magic upon
+database disconnection. If you need such functionality see L</txn_do>.
+
+=cut
+
+sub txn_scope_guard {
+  return DBIx::Class::Storage::TxnScopeGuard->new($_[0]);
+}
+
+=head2 sql_maker
+
+Returns a C<sql_maker> object - normally an object of class
+C<DBIx::Class::SQLAHacks>.
+
+=cut
+
+sub sql_maker { die "Virtual method!" }
+
+=head2 debug
+
+Causes trace information to be emitted on the C<debugobj> object.
+(or C<STDERR> if C<debugobj> has not specifically been set).
+
+This is the equivalent to setting L</DBIC_TRACE> in your
+shell environment.
+
+=head2 debugfh
+
+Set or retrieve the filehandle used for trace/debug output.  This should be
+an IO::Handle compatible ojbect (only the C<print> method is used.  Initially
+set to be STDERR - although see information on the
+L<DBIC_TRACE> environment variable.
+
+=cut
+
+sub debugfh {
+    my $self = shift;
+
+    if ($self->debugobj->can('debugfh')) {
+        return $self->debugobj->debugfh(@_);
+    }
+}
+
+=head2 debugobj
+
+Sets or retrieves the object used for metric collection. Defaults to an instance
+of L<DBIx::Class::Storage::Statistics> that is compatible with the original
+method of using a coderef as a callback.  See the aforementioned Statistics
+class for more information.
+
+=head2 debugcb
+
+Sets a callback to be executed each time a statement is run; takes a sub
+reference.  Callback is executed as $sub->($op, $info) where $op is
+SELECT/INSERT/UPDATE/DELETE and $info is what would normally be printed.
+
+See L<debugobj> for a better way.
+
+=cut
+
+sub debugcb {
+    my $self = shift;
+
+    if ($self->debugobj->can('callback')) {
+        return $self->debugobj->callback(@_);
+    }
+}
+
+=head2 cursor_class
+
+The cursor class for this Storage object.
+
+=cut
+
+=head2 deploy
+
+Deploy the tables to storage (CREATE TABLE and friends in a SQL-based
+Storage class). This would normally be called through
+L<DBIx::Class::Schema/deploy>.
+
+=cut
+
+sub deploy { die "Virtual method!" }
+
+=head2 connect_info
+
+The arguments of C<connect_info> are always a single array reference,
+and are Storage-handler specific.
+
+This is normally accessed via L<DBIx::Class::Schema/connection>, which
+encapsulates its argument list in an arrayref before calling
+C<connect_info> here.
+
+=cut
+
+sub connect_info { die "Virtual method!" }
+
+=head2 select
+
+Handle a select statement.
+
+=cut
+
+sub select { die "Virtual method!" }
+
+=head2 insert
+
+Handle an insert statement.
+
+=cut
+
+sub insert { die "Virtual method!" }
+
+=head2 update
+
+Handle an update statement.
+
+=cut
+
+sub update { die "Virtual method!" }
+
+=head2 delete
+
+Handle a delete statement.
+
+=cut
+
+sub delete { die "Virtual method!" }
+
+=head2 select_single
+
+Performs a select, fetch and return of data - handles a single row
+only.
+
+=cut
+
+sub select_single { die "Virtual method!" }
+
+=head2 columns_info_for
+
+Returns metadata for the given source's columns.  This
+is *deprecated*, and will be removed before 1.0.  You should
+be specifying the metadata yourself if you need it.
+
+=cut
+
+sub columns_info_for { die "Virtual method!" }
+
+=head1 ENVIRONMENT VARIABLES
+
+=head2 DBIC_TRACE
+
+If C<DBIC_TRACE> is set then trace information
+is produced (as when the L<debug> method is set).
+
+If the value is of the form C<1=/path/name> then the trace output is
+written to the file C</path/name>.
+
+This environment variable is checked when the storage object is first
+created (when you call connect on your schema).  So, run-time changes 
+to this environment variable will not take effect unless you also 
+re-connect on your schema.
+
+=head2 DBIX_CLASS_STORAGE_DBI_DEBUG
+
+Old name for DBIC_TRACE
+
+=head1 SEE ALSO
+
+L<DBIx::Class::Storage::DBI> - reference storage implementation using
+SQL::Abstract and DBI.
+
+=head1 AUTHORS
+
+Matt S. Trout <mst@shadowcatsystems.co.uk>
+
+Andy Grundman <andy@hybridized.org>
+
+=head1 LICENSE
+
+You may distribute this code under the same terms as Perl itself.
+
+=cut
+
 1;