Class: SQLite3::Backup

Inherits:
Object
  • Object
show all
Defined in:
ext/sqlite3/backup.c

Instance Method Summary collapse

Constructor Details

#SQLite3::Backup.new(dstdb, dstname, srcdb, srcname) ⇒ Object

Initialize backup the backup.

dstdb:

the destination SQLite3::Database object.

dstname:

the destination's database name.

srcdb:

the source SQLite3::Database object.

srcname:

the source's database name.

The database name is “main”, “temp”, or the name specified in an ATTACH statement.

This feature requires SQLite 3.6.11 or later.

require 'sqlite3'
sdb = SQLite3::Database.new('src.sqlite3')

ddb = SQLite3::Database.new(':memory:')
b = SQLite3::Backup.new(ddb, 'main', sdb, 'main')
p [b.remaining, b.pagecount] # invalid value; for example [0, 0]
begin
  p b.step(1) #=> OK or DONE
  p [b.remaining, b.pagecount]
end while b.remaining > 0
b.finish

ddb = SQLite3::Database.new(':memory:')
b = SQLite3::Backup.new(ddb, 'main', sdb, 'main')
b.step(-1) #=> DONE
b.finish


59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
# File 'ext/sqlite3/backup.c', line 59

static VALUE initialize(VALUE self, VALUE dstdb, VALUE dstname, VALUE srcdb, VALUE srcname)
{
  sqlite3BackupRubyPtr ctx;
  sqlite3RubyPtr ddb_ctx, sdb_ctx;
  sqlite3_backup *pBackup;

  Data_Get_Struct(self, sqlite3BackupRuby, ctx);
  Data_Get_Struct(dstdb, sqlite3Ruby, ddb_ctx);
  Data_Get_Struct(srcdb, sqlite3Ruby, sdb_ctx);

  if(!sdb_ctx->db)
    rb_raise(rb_eArgError, "cannot backup from a closed database");
  if(!ddb_ctx->db)
    rb_raise(rb_eArgError, "cannot backup to a closed database");

  pBackup = sqlite3_backup_init(ddb_ctx->db, StringValuePtr(dstname),
    sdb_ctx->db, StringValuePtr(srcname));
  if( pBackup ){
    ctx->p = pBackup;
  }
  else {
    CHECK(ddb_ctx->db, sqlite3_errcode(ddb_ctx->db));
  }

  return self;
}

Instance Method Details

#SQLite3::BackupObject

Destroy the backup object.



110
111
112
113
114
115
116
117
118
119
# File 'ext/sqlite3/backup.c', line 110

static VALUE finish(VALUE self)
{
  sqlite3BackupRubyPtr ctx;

  Data_Get_Struct(self, sqlite3BackupRuby, ctx);
  REQUIRE_OPEN_BACKUP(ctx);
  (void)sqlite3_backup_finish(ctx->p);
  ctx->p = NULL;
  return Qnil;
}

#SQLite3::BackupObject

Returns the total number of pages in the source database file.

Note that the value is only updated after step() is called, so before calling step() returned value is invalid.



144
145
146
147
148
149
150
151
# File 'ext/sqlite3/backup.c', line 144

static VALUE pagecount(VALUE self)
{
  sqlite3BackupRubyPtr ctx;

  Data_Get_Struct(self, sqlite3BackupRuby, ctx);
  REQUIRE_OPEN_BACKUP(ctx);
  return INT2NUM(sqlite3_backup_pagecount(ctx->p));
}

#SQLite3::BackupObject

Returns the number of pages still to be backed up.

Note that the value is only updated after step() is called, so before calling step() returned value is invalid.



128
129
130
131
132
133
134
135
# File 'ext/sqlite3/backup.c', line 128

static VALUE remaining(VALUE self)
{
  sqlite3BackupRubyPtr ctx;

  Data_Get_Struct(self, sqlite3BackupRuby, ctx);
  REQUIRE_OPEN_BACKUP(ctx);
  return INT2NUM(sqlite3_backup_remaining(ctx->p));
}

#SQLite3::BackupObject

Copy database pages up to nPage. If negative, copy all remaining source pages.

If all pages are copied, it returns SQLite3::Constants::ErrorCode::DONE. When coping is not done, it returns SQLite3::Constants::ErrorCode::OK. When some errors occur, it returns the error code.



95
96
97
98
99
100
101
102
103
104
# File 'ext/sqlite3/backup.c', line 95

static VALUE step(VALUE self, VALUE nPage)
{
  sqlite3BackupRubyPtr ctx;
  int status;

  Data_Get_Struct(self, sqlite3BackupRuby, ctx);
  REQUIRE_OPEN_BACKUP(ctx);
  status = sqlite3_backup_step(ctx->p, NUM2INT(nPage));
  return INT2NUM(status);
}