| 123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329 | /******************************************************************************* copyright: Copyright (c) 2004 Kris Bell. All rights reserved license: BSD style: $(LICENSE) version: Initial release: March 2004 Outback release: December 2006 author: Kris *******************************************************************************/ module tango.io.model.IConduit; /******************************************************************************* Conduits provide virtualized access to external content, and represent things like files or Internet connections. Conduits expose a pair of streams, are modelled by tango.io.model.IConduit, and are implemented via classes such as File & SocketConduit. Additional kinds of conduit are easy to construct: one either subclasses tango.io.device.Conduit, or implements tango.io.model.IConduit. A conduit typically reads and writes from/to an IBuffer in large chunks, typically the entire buffer. Alternatively, one can invoke input.read(dst[]) and/or output.write(src[]) directly. *******************************************************************************/ interface IConduit : InputStream, OutputStream { /*********************************************************************** Return a preferred size for buffering conduit I/O ***********************************************************************/ abstract size_t bufferSize (); /*********************************************************************** Return the name of this conduit ***********************************************************************/ abstract char[] toString (); /*********************************************************************** Is the conduit alive? ***********************************************************************/ abstract bool isAlive (); /*********************************************************************** Release external resources ***********************************************************************/ abstract void detach (); /*********************************************************************** Throw a generic IO exception with the provided msg ***********************************************************************/ abstract void error (char[] msg); /*********************************************************************** All streams now support seek(), so this is used to signal a seekable conduit instead ***********************************************************************/ interface Seek {} /*********************************************************************** Indicates the conduit supports resize/truncation ***********************************************************************/ interface Truncate { void truncate (long size); } } /******************************************************************************* Describes how to make an IO entity usable with selectors *******************************************************************************/ interface ISelectable { version (Windows) alias void* Handle; /// opaque OS file-handle else typedef int Handle = -1; /// opaque OS file-handle /*********************************************************************** Models a handle-oriented device. TODO: figure out how to avoid exposing this in the general case ***********************************************************************/ Handle fileHandle (); } /******************************************************************************* The common attributes of streams *******************************************************************************/ interface IOStream { const Eof = -1; /// the End-of-Flow identifer /*********************************************************************** The anchor positions supported by seek() ***********************************************************************/ enum Anchor { Begin = 0, Current = 1, End = 2, }; /*********************************************************************** Move the stream position to the given offset from the provided anchor point, and return adjusted position. Those conduits which don't support seeking will throw an IOException (and don't implement IConduit.Seek) ***********************************************************************/ long seek (long offset, Anchor anchor = Anchor.Begin); /*********************************************************************** Return the host conduit ***********************************************************************/ IConduit conduit (); /*********************************************************************** Flush buffered content. For InputStream this is equivalent to clearing buffered content ***********************************************************************/ IOStream flush (); /*********************************************************************** Close the input ***********************************************************************/ void close (); /*********************************************************************** Marks a stream that performs read/write mutation, rather than generic decoration. This is used to identify those stream that should explicitly not share an upstream buffer with downstream siblings. Many streams add simple decoration (such as DataStream) while others are merely template aliases. However, streams such as EndianStream mutate content as it passes through the read and write methods, which must be respected. On one hand we wish to share a single buffer instance, while on the other we must ensure correct data flow through an arbitrary combinations of streams. There are two stream variations: one which operate directly upon memory (and thus must have access to a buffer) and another that prefer to have buffered input (for performance reasons) but can operate without. EndianStream is an example of the former, while DataStream represents the latter. In order to sort out who gets what, each stream makes a request for an upstream buffer at construction time. The request has an indication of the intended purpose (array-based access, or not). ***********************************************************************/ interface Mutator {} } /******************************************************************************* The Tango input stream *******************************************************************************/ interface InputStream : IOStream { /*********************************************************************** Read from stream into a target array. The provided dst will be populated with content from the stream. Returns the number of bytes read, which may be less than requested in dst. Eof is returned whenever an end-of-flow condition arises. ***********************************************************************/ size_t read (void[] dst); /*********************************************************************** Load the bits from a stream, and return them all in an array. The dst array can be provided as an option, which will be expanded as necessary to consume the input. Returns an array representing the content, and throws IOException on error ***********************************************************************/ void[] load (size_t max = -1); /*********************************************************************** Return the upstream source ***********************************************************************/ InputStream input (); } /******************************************************************************* The Tango output stream *******************************************************************************/ interface OutputStream : IOStream { /*********************************************************************** Write to stream from a source array. The provided src content will be written to the stream. Returns the number of bytes written from src, which may be less than the quantity provided. Eof is returned when an end-of-flow condition arises. ***********************************************************************/ size_t write (void[] src); /*********************************************************************** Transfer the content of another stream to this one. Returns a reference to this class, and throws IOException on failure. ***********************************************************************/ OutputStream copy (InputStream src, size_t max = -1); /*********************************************************************** Return the upstream sink ***********************************************************************/ OutputStream output (); } /******************************************************************************* A buffered input stream *******************************************************************************/ interface InputBuffer : InputStream { void[] slice (); bool next (size_t delegate(void[]) scan); size_t reader (size_t delegate(void[]) consumer); } /******************************************************************************* A buffered output stream *******************************************************************************/ interface OutputBuffer : OutputStream { alias append opCall; void[] slice (); OutputBuffer append (void[]); size_t writer (size_t delegate(void[]) producer); } |