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package com.oracle.truffle.api.debug;

import java.net.URI;
import java.util.function.Predicate;

import com.oracle.truffle.api.instrumentation.SourceFilter;
import com.oracle.truffle.api.instrumentation.SourceSectionFilter;
import com.oracle.truffle.api.instrumentation.SourceSectionFilter.IndexRange;
import com.oracle.truffle.api.instrumentation.TruffleInstrument;
import com.oracle.truffle.api.source.Source;
import com.oracle.truffle.api.source.SourceSection;

Description of a textual location in guest language source code where a Breakpoint can be installed. 

The location's key identifies a particular unit of source code, for example a Source or URI. It can be optionally specialized to a 1-based line number and if it is, then it may also be optionally specialized to a 1-based column number. 
/**
 * Description of a textual location in guest language source code where a {@link Breakpoint} can be
 * installed.
 * <p>
 * The location's <em>key</em> identifies a particular unit of source code, for example a
 * {@link Source} or {@link URI}. It can be optionally specialized to a 1-based line number and if
 * it is, then it may also be optionally specialized to a 1-based column number.
 * </p>
 *
 */
abstract class BreakpointLocation {

    protected final SourceElement[] sourceElements;

    protected BreakpointLocation(SourceElement[] sourceElements) {
        this.sourceElements = sourceElements;
    }

    
A source location with key == null that always matches. /**
     * A source location with {@code key == null} that always matches.
     */
    static final BreakpointLocation ANY = new BreakpointSourceLocation();

    static final URI ANY_SOURCE = URI.create("");

    static BreakpointLocation create(Object key, SourceElement[] sourceElements, SourceSection sourceSection) {
        return new BreakpointSourceLocation(key, sourceElements, sourceSection);
    }

    static BreakpointLocation create(Object key, SourceElement[] sourceElements, int line, int column) {
        return new BreakpointSourceLocation(key, sourceElements, line, column);
    }

    static BreakpointLocation create(SourceElement[] sourceElements, SuspensionFilter filter) {
        return new BreakpointFilteredLocation(sourceElements, filter);
    }

    final boolean containsRoot() {
        if (sourceElements == null) {
            return true;
        }
        for (SourceElement elem : sourceElements) {
            if (SourceElement.ROOT == elem) {
                return true;
            }
        }
        return false;
    }

    abstract SourceFilter createSourceFilter();

    abstract Predicate<Source> createSourcePredicate();

    abstract boolean canAdjustLocation();

    abstract SourceSection adjustLocation(Source source, TruffleInstrument.Env env, SuspendAnchor suspendAnchor);

    abstract SourceSectionFilter createLocationFilter(Source source, SuspendAnchor suspendAnchor);

    private static void setTags(SourceSectionFilter.Builder f, SourceElement[] sourceElements) {
        Class<?>[] elementTags = new Class<?>[sourceElements.length];
        for (int i = 0; i < elementTags.length; i++) {
            elementTags[i] = sourceElements[i].getTag();
        }
        f.tagIs(elementTags);
    }

    private static final class BreakpointSourceLocation extends BreakpointLocation {

        private final Object key;
        private final SourceSection sourceSection;
        private int line;
        private int column;

        
Params:
key – non-null source identifier
line – 1-based line number, -1 for unspecified/**
         * @param key non-null source identifier
         * @param line 1-based line number, -1 for unspecified
         */
        BreakpointSourceLocation(Object key, SourceElement[] sourceElements, SourceSection sourceSection) {
            super(sourceElements);
            assert key instanceof Source || key instanceof URI;
            this.key = key;
            this.sourceSection = sourceSection;
            this.line = -1;
            this.column = -1;
        }

        
Params:
key – non-null source identifier
line – 1-based line number
column – 1-based column number, -1 for unspecified/**
         * @param key non-null source identifier
         * @param line 1-based line number
         * @param column 1-based column number, -1 for unspecified
         */
        BreakpointSourceLocation(Object key, SourceElement[] sourceElements, int line, int column) {
            super(sourceElements);
            assert key instanceof Source || key instanceof URI;
            assert line > 0 || line == -1;
            assert column > 0 || column == -1;
            this.key = key;
            this.line = line;
            this.column = column;
            this.sourceSection = null;
        }

        private BreakpointSourceLocation() {
            super(null);
            this.key = null;
            this.line = -1;
            this.column = -1;
            this.sourceSection = null;
        }

        @Override
        SourceFilter createSourceFilter() {
            if (key == null) {
                return null;
            }
            SourceFilter.Builder f = SourceFilter.newBuilder();
            if (key instanceof URI) {
                f.sourceIs(createSourcePredicate());
            } else {
                assert key instanceof Source;
                Source s = (Source) key;
                f.sourceIs(s);
            }
            return f.build();
        }

        @Override
        Predicate<Source> createSourcePredicate() {
            if (key == null) {
                return null;
            }
            if (key instanceof URI) {
                if (key == ANY_SOURCE) {
                    return new Predicate<Source>() {
                        @Override
                        public boolean test(Source s) {
                            return true;
                        }
                    };
                }
                final URI sourceUri = (URI) key;
                final String sourceRawPath = sourceUri.getRawPath() != null ? sourceUri.getRawPath() : sourceUri.getRawSchemeSpecificPart();
                return new Predicate<Source>() {
                    @Override
                    public boolean test(Source s) {
                        URI uri = s.getURI();
                        if (uri.isAbsolute()) {
                            return sourceUri.equals(uri);
                        } else {
                            return sourceRawPath != null && sourceRawPath.endsWith(uri.getRawPath());
                        }
                    }

                    @Override
                    public String toString() {
                        return "URI equals " + sourceUri;
                    }
                };
            } else {
                assert key instanceof Source;
                Source source = (Source) key;
                return new Predicate<Source>() {
                    @Override
                    public boolean test(Source s) {
                        return source.equals(s);
                    }
                };
            }
        }

        @Override
        boolean canAdjustLocation() {
            return key != null;
        }

        @Override
        SourceSection adjustLocation(Source source, TruffleInstrument.Env env, SuspendAnchor suspendAnchor) {
            if (sourceSection != null) {
                return sourceSection;
            }
            if (key == null) {
                return null;
            }
            if (line == -1) {
                return source.createUnavailableSection();
            }
            boolean hasColumn = column > 0;
            SourceSection location = SuspendableLocationFinder.findNearest(source, sourceElements, line, column, suspendAnchor, env);
            if (location != null) {
                switch (suspendAnchor) {
                    case BEFORE:
                        line = location.getStartLine();
                        if (hasColumn) {
                            column = location.getStartColumn();
                        }
                        break;
                    case AFTER:
                        line = location.getEndLine();
                        if (hasColumn) {
                            column = location.getEndColumn();
                        }
                        break;
                    default:
                        throw new IllegalArgumentException("Unknown suspend anchor: " + suspendAnchor);
                }
            }
            return location;
        }

        @Override
        SourceSectionFilter createLocationFilter(Source source, SuspendAnchor suspendAnchor) {
            SourceSectionFilter.Builder f = SourceSectionFilter.newBuilder();
            if (key == null) {
                return f.tagIs(DebuggerTags.AlwaysHalt.class).build();
            }
            if (key != ANY_SOURCE) {
                if (source != null) {
                    f.sourceIs(source);
                } else {
                    f.sourceFilter(createSourceFilter());
                }
            }
            if (line != -1) {
                switch (suspendAnchor) {
                    case BEFORE:
                        f.lineStartsIn(IndexRange.byLength(line, 1));
                        if (column != -1) {
                            f.columnStartsIn(IndexRange.byLength(column, 1));
                        }
                        break;
                    case AFTER:
                        f.lineEndsIn(IndexRange.byLength(line, 1));
                        if (column != -1) {
                            f.columnEndsIn(IndexRange.byLength(column, 1));
                        }
                        break;
                    default:
                        throw new IllegalArgumentException(suspendAnchor.name());
                }
            }
            if (sourceSection != null) {
                f.sourceSectionEquals(sourceSection);
            }
            setTags(f, sourceElements);
            return f.build();
        }

        @Override
        public String toString() {
            String keyDescription;
            if (key == null) {
                keyDescription = "AlwaysHalt";
            } else if (key instanceof Source) {
                keyDescription = "sourceName=" + ((Source) key).getName();
            } else if (key instanceof URI) {
                keyDescription = "uri=" + ((URI) key).toString();
            } else {
                keyDescription = key.toString();
            }
            return keyDescription + ", line=" + line + ", column=" + column;
        }

    }

    private static final class BreakpointFilteredLocation extends BreakpointLocation {

        private final SuspensionFilter filter;

        BreakpointFilteredLocation(SourceElement[] sourceElements, SuspensionFilter filter) {
            super(sourceElements);
            this.filter = filter;
        }

        @Override
        SourceFilter createSourceFilter() {
            return null;
        }

        @Override
        Predicate<Source> createSourcePredicate() {
            return null;
        }

        @Override
        boolean canAdjustLocation() {
            return false;
        }

        @Override
        SourceSection adjustLocation(Source source, TruffleInstrument.Env env, SuspendAnchor suspendAnchor) {
            return null;
        }

        @Override
        SourceSectionFilter createLocationFilter(Source source, SuspendAnchor suspendAnchor) {
            SourceSectionFilter.Builder f = SourceSectionFilter.newBuilder();
            SourceFilter.Builder sourceFilterBuilder = SourceFilter.newBuilder();
            if (filter != null) {
                Predicate<Source> sourcePredicate = filter.getSourcePredicate();
                if (sourcePredicate != null) {
                    sourceFilterBuilder.sourceIs(sourcePredicate);
                }
                sourceFilterBuilder.includeInternal(filter.isInternalIncluded());
            }
            SourceFilter sourceFilter = sourceFilterBuilder.build();
            f.sourceFilter(sourceFilter);
            setTags(f, sourceElements);
            return f.build();
        }

    }
}