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//go:build !appengine && !plan9 && !js && !wasip1 && !wasi
// +build !appengine,!plan9,!js,!wasip1,!wasi
package maxminddb
import (
"os"
"runtime"
)
// Open takes a string path to a MaxMind DB file and returns a Reader
// structure or an error. The database file is opened using a memory map
// on supported platforms. On platforms without memory map support, such
// as WebAssembly or Google App Engine, the database is loaded into memory.
// Use the Close method on the Reader object to return the resources to the system.
func Open(file string) (*Reader, error) {
mapFile, err := os.Open(file)
if err != nil {
_ = mapFile.Close()
return nil, err
}
stats, err := mapFile.Stat()
if err != nil {
_ = mapFile.Close()
return nil, err
}
fileSize := int(stats.Size())
mmap, err := mmap(int(mapFile.Fd()), fileSize)
if err != nil {
_ = mapFile.Close()
return nil, err
}
if err := mapFile.Close(); err != nil {
//nolint:errcheck // we prefer to return the original error
munmap(mmap)
return nil, err
}
reader, err := FromBytes(mmap)
if err != nil {
//nolint:errcheck // we prefer to return the original error
munmap(mmap)
return nil, err
}
reader.hasMappedFile = true
runtime.SetFinalizer(reader, (*Reader).Close)
return reader, nil
}
// Close returns the resources used by the database to the system.
func (r *Reader) Close() error {
var err error
if r.hasMappedFile {
runtime.SetFinalizer(r, nil)
r.hasMappedFile = false
err = munmap(r.buffer)
}
r.buffer = nil
return err
}
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