classreader.java

jboss规则引擎

                        for ( ; k > 0; --k ) {
                            desc = readUTF8( v,
                                             c );
                            v += 2;
                            v = readAnnotationValues( v,
                                                      c,
                                                      fv.visitAnnotation( desc,
                                                                          j != 0 ) );
                        }
                    }
                }
                while ( cattrs != null ) {
                    attr = cattrs.next;
                    cattrs.next = null;
                    fv.visitAttribute( cattrs );
                    cattrs = attr;
                }
                fv.visitEnd();
            }
        }

        // visits the methods
        i = readUnsignedShort( u );
        u += 2;
        for ( ; i > 0; --i ) {
            final int u0 = u + 6;
            access = readUnsignedShort( u );
            name = readUTF8( u + 2,
                             c );
            desc = readUTF8( u + 4,
                             c );
            signature = null;
            anns = 0;
            ianns = 0;
            int dann = 0;
            int mpanns = 0;
            int impanns = 0;
            cattrs = null;
            v = 0;
            w = 0;

            // looks for Code and Exceptions attributes
            j = readUnsignedShort( u + 6 );
            u += 8;
            for ( ; j > 0; --j ) {
                attrName = readUTF8( u,
                                     c );
                u += 2;
                final int attrSize = readInt( u );
                u += 4;
                if ( attrName.equals( "Code" ) ) {
                    v = u;
                } else if ( attrName.equals( "Exceptions" ) ) {
                    w = u;
                } else if ( attrName.equals( "Synthetic" ) ) {
                    access |= Opcodes.ACC_SYNTHETIC;
                } else if ( attrName.equals( "Varargs" ) ) {
                    access |= Opcodes.ACC_VARARGS;
                } else if ( attrName.equals( "Bridge" ) ) {
                    access |= Opcodes.ACC_BRIDGE;
                } else if ( attrName.equals( "Deprecated" ) ) {
                    access |= Opcodes.ACC_DEPRECATED;
                } else if ( attrName.equals( "Signature" ) ) {
                    signature = readUTF8( u,
                                          c );
                } else if ( attrName.equals( "AnnotationDefault" ) ) {
                    dann = u;
                } else if ( attrName.equals( "RuntimeVisibleAnnotations" ) ) {
                    anns = u;
                } else if ( attrName.equals( "RuntimeInvisibleAnnotations" ) ) {
                    ianns = u;
                } else if ( attrName.equals( "RuntimeVisibleParameterAnnotations" ) ) {
                    mpanns = u;
                } else if ( attrName.equals( "RuntimeInvisibleParameterAnnotations" ) ) {
                    impanns = u;
                } else {
                    attr = readAttribute( attrs,
                                          attrName,
                                          u,
                                          attrSize,
                                          c,
                                          -1,
                                          null );
                    if ( attr != null ) {
                        attr.next = cattrs;
                        cattrs = attr;
                    }
                }
                u += attrSize;
            }
            // reads declared exceptions
            String[] exceptions;
            if ( w == 0 ) {
                exceptions = null;
            } else {
                exceptions = new String[readUnsignedShort( w )];
                w += 2;
                for ( j = 0; j < exceptions.length; ++j ) {
                    exceptions[j] = readClass( w,
                                               c );
                    w += 2;
                }
            }

            // visits the method's code, if any
            final MethodVisitor mv = classVisitor.visitMethod( access,
                                                               name,
                                                               desc,
                                                               signature,
                                                               exceptions );

            if ( mv != null ) {
                /*
                 * if the returned MethodVisitor is in fact a MethodWriter, it
                 * means there is no method adapter between the reader and the
                 * writer. If, in addition, the writer's constant pool was
                 * copied from this reader (mw.cw.cr == this), and the signature
                 * and exceptions of the method have not been changed, then it
                 * is possible to skip all visit events and just copy the
                 * original code of the method to the writer (the access, name
                 * and descriptor can have been changed, this is not important
                 * since they are not copied as is from the reader).
                 */
                if ( mv instanceof MethodWriter ) {
                    final MethodWriter mw = (MethodWriter) mv;
                    if ( mw.cw.cr == this ) {
                        if ( signature == mw.signature ) {
                            boolean sameExceptions = false;
                            if ( exceptions == null ) {
                                sameExceptions = mw.exceptionCount == 0;
                            } else {
                                if ( exceptions.length == mw.exceptionCount ) {
                                    sameExceptions = true;
                                    for ( j = exceptions.length - 1; j >= 0; --j ) {
                                        w -= 2;
                                        if ( mw.exceptions[j] != readUnsignedShort( w ) ) {
                                            sameExceptions = false;
                                            break;
                                        }
                                    }
                                }
                            }
                            if ( sameExceptions ) {
                                /*
                                 * we do not copy directly the code into
                                 * MethodWriter to save a byte array copy
                                 * operation. The real copy will be done in
                                 * ClassWriter.toByteArray().
                                 */
                                mw.classReaderOffset = u0;
                                mw.classReaderLength = u - u0;
                                continue;
                            }
                        }
                    }
                }
                if ( dann != 0 ) {
                    final AnnotationVisitor dv = mv.visitAnnotationDefault();
                    readAnnotationValue( dann,
                                         c,
                                         null,
                                         dv );
                    dv.visitEnd();
                }
                for ( j = 1; j >= 0; --j ) {
                    w = j == 0 ? ianns : anns;
                    if ( w != 0 ) {
                        k = readUnsignedShort( w );
                        w += 2;
                        for ( ; k > 0; --k ) {
                            desc = readUTF8( w,
                                             c );
                            w += 2;
                            w = readAnnotationValues( w,
                                                      c,
                                                      mv.visitAnnotation( desc,
                                                                          j != 0 ) );
                        }
                    }
                }
                if ( mpanns != 0 ) {
                    readParameterAnnotations( mpanns,
                                              c,
                                              true,
                                              mv );
                }
                if ( impanns != 0 ) {
                    readParameterAnnotations( impanns,
                                              c,
                                              false,
                                              mv );
                }
                while ( cattrs != null ) {
                    attr = cattrs.next;
                    cattrs.next = null;
                    mv.visitAttribute( cattrs );
                    cattrs = attr;
                }
            }

            if ( mv != null && v != 0 ) {
                final int maxStack = readUnsignedShort( v );
                final int maxLocals = readUnsignedShort( v + 2 );
                final int codeLength = readInt( v + 4 );
                v += 8;

                final int codeStart = v;
                final int codeEnd = v + codeLength;

                mv.visitCode();

                // 1st phase: finds the labels
                int label;
                final Label[] labels = new Label[codeLength + 1];
                while ( v < codeEnd ) {
                    int opcode = b[v] & 0xFF;
                    switch ( ClassWriter.TYPE[opcode] ) {
                        case ClassWriter.NOARG_INSN :
                        case ClassWriter.IMPLVAR_INSN :
                            v += 1;
                            break;
                        case ClassWriter.LABEL_INSN :
                            label = v - codeStart + readShort( v + 1 );
                            if ( labels[label] == null ) {
                                labels[label] = new Label();
                            }
                            v += 3;
                            break;
                        case ClassWriter.LABELW_INSN :
                            label = v - codeStart + readInt( v + 1 );
                            if ( labels[label] == null ) {
                                labels[label] = new Label();
                            }
                            v += 5;
                            break;
                        case ClassWriter.WIDE_INSN :
                            opcode = b[v + 1] & 0xFF;
                            if ( opcode == Opcodes.IINC ) {
                                v += 6;
                            } else {
                                v += 4;
                            }
                            break;
                        case ClassWriter.TABL_INSN :
                            // skips 0 to 3 padding bytes
                            w = v - codeStart;
                            v = v + 4 - (w & 3);
                            // reads instruction
                            label = w + readInt( v );
                            v += 4;
                            if ( labels[label] == null ) {
                                labels[label] = new Label();
                            }
                            j = readInt( v );
                            v += 4;
                            j = readInt( v ) - j + 1;
                            v += 4;
                            for ( ; j > 0; --j ) {
                                label = w + readInt( v );
                                v += 4;
                                if ( labels[label] == null ) {
                                    labels[label] = new Label();
                                }
                            }
                            break;
                        case ClassWriter.LOOK_INSN :
                            // skips 0 to 3 padding bytes
                            w = v - codeStart;
                            v = v + 4 - (w & 3);
                            // reads instruction
                            label = w + readInt( v );
                            v += 4;
                            if ( labels[label] == null ) {
                                labels[label] = new Label();
                            }
                            j = readInt( v );
                            v += 4;
                            for ( ; j > 0; --j ) {
                                v += 4; // skips key
                                label = w + readInt( v );
                                v += 4;
                                if ( labels[label] == null ) {
                                    labels[label] = new Label();
                                }
                            }
                            break;
                        case ClassWriter.VAR_INSN :
                        case ClassWriter.SBYTE_INSN :
                        case ClassWriter.LDC_INSN :
                            v += 2;
                            break;
                        case ClassWriter.SHORT_INSN :
                        case ClassWriter.LDCW_INSN :
                        case ClassWriter.FIELDORMETH_INSN :
                        case ClassWriter.TYPE_INSN :
                        case ClassWriter.IINC_INSN :
                            v += 3;
                            break;