| 1 | package jrw.util; |
| 2 | |
| 3 | import jrw.*; |
| 4 | import java.nio.*; |
| 5 | import java.nio.channels.*; |
| 6 | import java.nio.charset.*; |
| 7 | |
| 8 | public abstract class LazyPChannel implements ReadableByteChannel { |
| 9 | private ByteBuffer curbuf = null; |
| 10 | private boolean eof = false; |
| 11 | private CharsetEncoder enc = null; |
| 12 | private Runnable rem = null; |
| 13 | |
| 14 | protected boolean write(byte[] data, int off, int len) { |
| 15 | if(rem != null) throw(new IllegalStateException("buffer filled")); |
| 16 | int t = Math.min(curbuf.remaining(), len); |
| 17 | curbuf.put(data, off, t); |
| 18 | if(len > t) { |
| 19 | rem = () -> write(data, off + t, len - t); |
| 20 | return(true); |
| 21 | } |
| 22 | return(false); |
| 23 | } |
| 24 | protected boolean write(byte[] data) {return(write(data, 0, data.length));} |
| 25 | |
| 26 | protected boolean write(CharBuffer buf) { |
| 27 | if(rem != null) throw(new IllegalStateException("buffer filled")); |
| 28 | if(enc == null) |
| 29 | enc = charset().newEncoder(); |
| 30 | while(true) { |
| 31 | int pp = buf.position(); |
| 32 | CoderResult res = enc.encode(buf, curbuf, false); |
| 33 | if(buf.remaining() == 0) |
| 34 | return(false); |
| 35 | if(res.isUnderflow()) { |
| 36 | if(pp == buf.position()) { |
| 37 | /* XXX? Not sure if this can be expected to |
| 38 | * happen. I'm not aware of any charsets that should |
| 39 | * require it, and it would complicate the design |
| 40 | * significantly. */ |
| 41 | throw(new RuntimeException("encoder not consuming input")); |
| 42 | } |
| 43 | } else if(res.isOverflow()) { |
| 44 | rem = () -> write(buf); |
| 45 | return(true); |
| 46 | } else { |
| 47 | try { |
| 48 | res.throwException(); |
| 49 | } catch(CharacterCodingException e) { |
| 50 | throw(new RuntimeException(e)); |
| 51 | } |
| 52 | } |
| 53 | } |
| 54 | } |
| 55 | |
| 56 | protected boolean write(CharSequence chars) { |
| 57 | CharBuffer buf = (chars instanceof CharBuffer) ? ((CharBuffer)chars).duplicate() : CharBuffer.wrap(chars); |
| 58 | return(write(buf)); |
| 59 | } |
| 60 | |
| 61 | private void encflush2() { |
| 62 | while(true) { |
| 63 | CoderResult res = enc.flush(curbuf); |
| 64 | if(res.isOverflow()) { |
| 65 | rem = this::encflush1; |
| 66 | return; |
| 67 | } else if(res.isUnderflow()) { |
| 68 | return; |
| 69 | } else { |
| 70 | try { |
| 71 | res.throwException(); |
| 72 | } catch(CharacterCodingException e) { |
| 73 | throw(new RuntimeException(e)); |
| 74 | } |
| 75 | } |
| 76 | } |
| 77 | } |
| 78 | |
| 79 | private void encflush1() { |
| 80 | CharBuffer empty = CharBuffer.wrap(""); |
| 81 | while(true) { |
| 82 | CoderResult res = enc.encode(empty, curbuf, true); |
| 83 | if(res.isOverflow()) { |
| 84 | rem = this::encflush1; |
| 85 | return; |
| 86 | } else if(res.isUnderflow()) { |
| 87 | rem = this::encflush2; |
| 88 | return; |
| 89 | } else { |
| 90 | try { |
| 91 | res.throwException(); |
| 92 | } catch(CharacterCodingException e) { |
| 93 | throw(new RuntimeException(e)); |
| 94 | } |
| 95 | } |
| 96 | } |
| 97 | } |
| 98 | |
| 99 | private void encflush() { |
| 100 | if(enc != null) |
| 101 | rem = this::encflush1; |
| 102 | } |
| 103 | |
| 104 | protected Charset charset() {return(Http.UTF8);} |
| 105 | |
| 106 | protected abstract boolean produce(); |
| 107 | |
| 108 | public int read(ByteBuffer buf) { |
| 109 | curbuf = buf; |
| 110 | try { |
| 111 | int op = buf.position(); |
| 112 | while(buf.remaining() > 0) { |
| 113 | Runnable rem = this.rem; |
| 114 | this.rem = null; |
| 115 | if(rem != null) { |
| 116 | rem.run(); |
| 117 | } else { |
| 118 | if(eof) { |
| 119 | break; |
| 120 | } else if(produce()) { |
| 121 | encflush(); |
| 122 | eof = true; |
| 123 | } |
| 124 | } |
| 125 | } |
| 126 | if(eof && (buf.position() == op)) |
| 127 | return(-1); |
| 128 | return(buf.position() - op); |
| 129 | } finally { |
| 130 | curbuf = null; |
| 131 | } |
| 132 | } |
| 133 | |
| 134 | public void close() {} |
| 135 | public boolean isOpen() {return(true);} |
| 136 | } |