Class: FileDescriptorHandle (private in UnixOperatingSystem

• Inheritance
• Class protocol
  • change & update
  • initialization
  • instance creation
• Instance protocol
  • error handling
  • file access
  • initialization
  • input/output
  • misc functions
  • private-accessing
  • queries
  • registering
  • releasing
  • waiting

Inheritance:

   Object
   |
   +--UnixOperatingSystem::FileDescriptorHandle

Package:

stx:libbasic

Category:

OS-Unix

Owner:

UnixOperatingSystem

Class protocol:

 update: aspect with: argument from: anObject

one of our registered handles has been collected

 initialize

self initialize

 for: aFileDescriptor

create an instance of myself for a given fileDescriptor

Instance protocol:

 error: anErrorSymbolOrErrno

got an error; arg is either a symbol specifying a primitive error
or the error number as returned by the OperatingSystem

 close

close the descriptor

 for: aFileDescriptor

create a file for a handle

 readBytes: count into: aByteBuffer startingAt: firstIndex

read count bytes into a byte-buffer;
Return the number of bytes read.
The read is non-blocking. If the operation would block
either an incomplete count or nil will be returned.

An exception is raised on any other error

Usage example(s):

|h buff n| h := OperatingSystem openFileForRead:'/etc/hosts'. buff := ByteArray new:1000. buff inspect. n := h readBytes:1000 into:buff startingAt:1. Transcript show:n; space; showCR:buff asString.

Usage example(s):

|h buff n| h := OperatingSystem openFileForRead:'/dev/cua0'. buff := ByteArray new:1000. buff inspect. n := h readBytes:1000 into:buff startingAt:1. Transcript show:n printString; space; showCR:buff asString.

 writeBytes: count from: aByteBuffer startingAt: firstIndex

write count bytes from a byte-buffer;
Return the number of bytes written (negative on error)

Usage example(s):

|h buff n| h := OperatingSystem createFileForReadWrite:'/tmp/xx'. buff := '12345678901234567890'. n := h writeBytes:10 from:buff startingAt:1.

Usage example(s):

|h buff n| h := OperatingSystem createFileForReadWrite:'/dev/cua0'. buff := '12345678901234567890'. n := h writeBytes:10 from:buff startingAt:1.

 nextError

retrieve the pending error from the current fileDescriptor
and raise an error exception.
This should be only called, when an error is pending.
Otherwise a byte may be lost

 seekTo: newPosition from: whence

seek to newPosition
whence is one of: #begin #current #end.
Return the new position.

Usage example(s):

|h buff n| h := OperatingSystem openFileForRead:'/etc/hosts'. h seekTo:10 from:#begin. buff := ByteArray new:1000. buff inspect. n := h readBytes:1000 into:buff startingAt:1. Transcript show:n; space; showCR:buff asString.

 selectWithTimeOut: millis

wait for aFileDesriptor to become ready; timeout after t milliseconds.
Return true, if i/o ok, false if timed-out or interrupted.
With 0 as timeout argument, this can be used to check for availability (poll)
of read-data.

 setBlocking: aBoolean

set/clear the blocking attribute - if set (which is the default)
a read on the fileDescriptor will block until data is available.
If cleared, a read operation will immediately return with a value of
nil if no data is available.

 fileDescriptor

return the (integer) fileDescriptor

 setFileDescriptor: anInteger

 canReadWithoutBlocking

return true, if data is available on a filedescriptor
(i.e. read is possible without blocking).
This depends on a working select or FIONREAD to be provided by the OS.

Usage example(s):

|h n| h := OperatingSystem openFileForRead:'/etc/hosts'. n := h canReadWithoutBlocking. h close. n

Usage example(s):

|h n| h := OperatingSystem openFileForRead:'/dev/ttyS0'. n := h canReadWithoutBlocking. h close. n

 canWriteWithoutBlocking

return true, if filedescriptor can be written without blocking

 isValid

answer true, if the handle is valid, i.e. connected to
a file or some other OS object

 numAvailableForRead

return the number of bytes available for reading, without blocking.

Usage example(s):

|h n| h := OperatingSystem openFileForRead:'/etc/hosts'. n := h numAvailableForRead. h close. n

 register

register myself as an open file

 invalidate

a file handle has become invalid

 readWaitWithTimeoutMs: timeout

suspend the current process, until the receiver
becomes ready for reading or a timeout (in milliseconds) expired.
If data is already available, return immediate.
Return true if a timeout occurred (i.e. false, if data is available).
The other threads are not affected by the wait.

 writeWaitWithTimeoutMs: timeout

suspend the current process, until the receiver
becomes ready for writing or a timeout (in seconds) expired.
Return true if a timeout occurred (i.e. false, if data is available).
Return immediate if the receiver is already ready.
The other threads are not affected by the wait.