2009-11-02 Jb Evain <jbevain@novell.com>

[mcs.git] / mcs / location.cs

//
// location.cs: Keeps track of the location of source code entity
//
// Author:
//   Miguel de Icaza
//   Atsushi Enomoto  <atsushi@ximian.com>
//
// Copyright 2001 Ximian, Inc.
// Copyright 2005 Novell, Inc.
//

using System;
using System.IO;
using System.Collections;
using Mono.CompilerServices.SymbolWriter;

namespace Mono.CSharp {
        /// <summary>
        ///   This is one single source file.
        /// </summary>
        /// <remarks>
        ///   This is intentionally a class and not a struct since we need
        ///   to pass this by reference.
        /// </remarks>
        public class SourceFile : ISourceFile {
                public readonly string Name;
                public readonly string Path;
                public readonly int Index;
                public bool AutoGenerated;
                public bool IsIncludeFile;

                SourceFileEntry file;
                byte[] guid, checksum;

                public SourceFile (string name, string path, int index, bool is_include)
                {
                        this.Index = index;
                        this.Name = name;
                        this.Path = path;
                        this.IsIncludeFile = is_include;
                }

                public SourceFileEntry SourceFileEntry {
                        get { return file; }
                }

                SourceFileEntry ISourceFile.Entry {
                        get { return file; }
                }

                public void SetChecksum (byte[] guid, byte[] checksum)
                {
                        this.guid = guid;
                        this.checksum = checksum;
                }

                public virtual void DefineSymbolInfo (MonoSymbolWriter symwriter)
                {
                        if (guid != null)
                                file = symwriter.DefineDocument (Path, guid, checksum);
                        else {
                                file = symwriter.DefineDocument (Path);
                                if (AutoGenerated)
                                        file.SetAutoGenerated ();
                        }
                }

                public override string ToString ()
                {
                        return String.Format ("SourceFile ({0}:{1}:{2}:{3})",
                                              Name, Path, Index, SourceFileEntry);
                }
        }

        public class CompilationUnit : SourceFile, ICompileUnit
        {
                CompileUnitEntry comp_unit;
                Hashtable include_files;
                Hashtable conditionals;

                public CompilationUnit (string name, string path, int index)
                        : base (name, path, index, false)
                { }

                public void AddFile (SourceFile file)
                {
                        if (include_files == null)
                                include_files = new Hashtable ();

                        if (!include_files.Contains (file.Path))
                                include_files.Add (file.Path, file);
                }

                public void AddDefine (string value)
                {
                        if (conditionals == null)
                                conditionals = new Hashtable (2);

                        conditionals [value] = true;
                }

                public void AddUndefine (string value)
                {
                        if (conditionals == null)
                                conditionals = new Hashtable (2);

                        conditionals [value] = null;
                }

                CompileUnitEntry ICompileUnit.Entry {
                        get { return comp_unit; }
                }

                public CompileUnitEntry CompileUnitEntry {
                        get { return comp_unit; }
                }

                public override void DefineSymbolInfo (MonoSymbolWriter symwriter)
                {
                        base.DefineSymbolInfo (symwriter);

                        comp_unit = symwriter.DefineCompilationUnit (SourceFileEntry);

                        if (include_files != null) {
                                foreach (SourceFile include in include_files.Values) {
                                        include.DefineSymbolInfo (symwriter);
                                        comp_unit.AddFile (include.SourceFileEntry);
                                }
                        }
                }

                public bool IsConditionalDefined (string value)
                {
                        if (conditionals != null) {
                                object res = conditionals [value];
                                if (res != null)
                                        return (bool)res;
                                
                                // When conditional was undefined
                                if (conditionals.Contains (value))
                                        return false;                                   
                        }

                        return RootContext.IsConditionalDefined (value);
                }
        }

        /// <summary>
        ///   Keeps track of the location in the program
        /// </summary>
        ///
        /// <remarks>
        ///   This uses a compact representation and a couple of auxiliary
        ///   structures to keep track of tokens to (file,line and column) 
        ///   mappings. The usage of the bits is:
        ///   
        ///     - 16 bits for "checkpoint" which is a mixed concept of
        ///       file and "line segment"
        ///     - 8 bits for line delta (offset) from the line segment
        ///     - 8 bits for column number.
        ///
        ///   http://lists.ximian.com/pipermail/mono-devel-list/2004-December/009508.html
        /// </remarks>
        public struct Location {
                int token; 

                struct Checkpoint {
                        public readonly int LineOffset;
                        public readonly int CompilationUnit;
                        public readonly int File;

                        public Checkpoint (int compile_unit, int file, int line)
                        {
                                File = file;
                                CompilationUnit = compile_unit;
                                LineOffset = line - (int) (line % (1 << line_delta_bits));
                        }
                }

                static ArrayList source_list;
                static ArrayList compile_units;
                static Hashtable source_files;
                static int checkpoint_bits;
                static int source_count;
                static int current_source;
                static int current_compile_unit;
                static int line_delta_bits;
                static int line_delta_mask;
                static int column_bits;
                static int column_mask;
                static Checkpoint [] checkpoints;
                static int checkpoint_index;
                
                public readonly static Location Null = new Location (-1);
                public static bool InEmacs;
                
                static Location ()
                {
                        source_files = new Hashtable ();
                        source_list = new ArrayList ();
                        compile_units = new ArrayList ();
                        current_source = 0;
                        current_compile_unit = 0;
                        checkpoints = new Checkpoint [10];
                }

                public static void Reset ()
                {
                        source_files = new Hashtable ();
                        source_list = new ArrayList ();
                        compile_units = new ArrayList ();
                        current_source = 0;
                        current_compile_unit = 0;
                        source_count = 0;
                }

                // <summary>
                //   This must be called before parsing/tokenizing any files.
                // </summary>
                static public void AddFile (Report r, string name)
                {
                        string path = Path.GetFullPath (name);

                        if (source_files.Contains (path)){
                                int id = (int) source_files [path];
                                string other_name = ((SourceFile) source_list [id - 1]).Name;
                                if (name.Equals (other_name))
                                        r.Warning (2002, 1, "Source file `{0}' specified multiple times", other_name);
                                else
                                        r.Warning (2002, 1, "Source filenames `{0}' and `{1}' both refer to the same file: {2}", name, other_name, path);
                                return;
                        }

                        source_files.Add (path, ++source_count);
                        CompilationUnit unit = new CompilationUnit (name, path, source_count);
                        source_list.Add (unit);
                        compile_units.Add (unit);
                }

                // IList<CompilationUnit>
                static public ArrayList SourceFiles {
                        get {
                                return compile_units;
                        }
                }

                // <summary>
                //   After adding all source files we want to compile with AddFile(), this method
                //   must be called to `reserve' an appropriate number of bits in the token for the
                //   source file.  We reserve some extra space for files we encounter via #line
                //   directives while parsing.
                // </summary>
                static public void Initialize ()
                {
                        checkpoints = new Checkpoint [source_list.Count * 2];
                        if (checkpoints.Length > 0)
                                checkpoints [0] = new Checkpoint (0, 0, 0);

                        column_bits = 8;
                        column_mask = 0xFF;
                        line_delta_bits = 8;
                        line_delta_mask = 0xFF00;
                        checkpoint_index = 0;
                        checkpoint_bits = 16;
                }

                // <remarks>
                //   This is used when we encounter a #line preprocessing directive.
                // </remarks>
                static public SourceFile LookupFile (CompilationUnit comp_unit, string name)
                {
                        string path;
                        if (!Path.IsPathRooted (name)) {
                                string root = Path.GetDirectoryName (comp_unit.Path);
                                path = Path.Combine (root, name);
                        } else
                                path = name;

                        if (!source_files.Contains (path)) {
                                if (source_count >= (1 << checkpoint_bits))
                                        return new SourceFile (name, path, 0, true);

                                source_files.Add (path, ++source_count);
                                SourceFile retval = new SourceFile (name, path, source_count, true);
                                source_list.Add (retval);
                                return retval;
                        }

                        int index = (int) source_files [path];
                        return (SourceFile) source_list [index - 1];
                }

                static public void Push (CompilationUnit compile_unit, SourceFile file)
                {
                        current_source = file != null ? file.Index : -1;
                        current_compile_unit = compile_unit != null ? compile_unit.Index : -1;
                        // File is always pushed before being changed.
                }

                // <remarks>
                //   If we're compiling with debugging support, this is called between parsing
                //   and code generation to register all the source files with the
                //   symbol writer.
                // </remarks>
                static public void DefineSymbolDocuments (MonoSymbolWriter symwriter)
                {
                        foreach (CompilationUnit unit in compile_units)
                                unit.DefineSymbolInfo (symwriter);
                }
                
                public Location (int row)
                        : this (row, 0)
                {
                }

                public Location (int row, int column)
                {
                        if (row <= 0)
                                token = 0;
                        else {
                                if (column > 254)
                                        column = 254;
                                if (column < 0)
                                        column = 255;
                                int target = -1;
                                int delta = 0;
                                int max = checkpoint_index < 10 ?
                                        checkpoint_index : 10;
                                for (int i = 0; i < max; i++) {
                                        int offset = checkpoints [checkpoint_index - i].LineOffset;
                                        delta = row - offset;
                                        if (delta >= 0 &&
                                                delta < (1 << line_delta_bits) &&
                                                checkpoints [checkpoint_index - i].File == current_source) {
                                                target = checkpoint_index - i;
                                                break;
                                        }
                                }
                                if (target == -1) {
                                        AddCheckpoint (current_compile_unit, current_source, row);
                                        target = checkpoint_index;
                                        delta = row % (1 << line_delta_bits);
                                }
                                long l = column +
                                        (long) (delta << column_bits) +
                                        (long) (target << (line_delta_bits + column_bits));
                                token = l > 0xFFFFFFFF ? 0 : (int) l;
                        }
                }

                static void AddCheckpoint (int compile_unit, int file, int row)
                {
                        if (checkpoints.Length == ++checkpoint_index) {
                                Checkpoint [] tmp = new Checkpoint [checkpoint_index * 2];
                                Array.Copy (checkpoints, tmp, checkpoints.Length);
                                checkpoints = tmp;
                        }
                        checkpoints [checkpoint_index] = new Checkpoint (compile_unit, file, row);
                }
                
                public override string ToString ()
                {
                        if (column_bits == 0 || InEmacs)
                                return Name + "(" + Row.ToString () + "):";
                        else
                                return Name + "(" + Row.ToString () + "," + Column.ToString () +
                                        (Column == column_mask ? "+):" : "):");
                }
                
                /// <summary>
                ///   Whether the Location is Null
                /// </summary>
                public bool IsNull {
                        get { return token == 0; }
                }

                public string Name {
                        get {
                                int index = File;
                                if (token == 0 || index == 0)
                                        return "Internal";

                                SourceFile file = (SourceFile) source_list [index - 1];
                                return file.Name;
                        }
                }

                int CheckpointIndex {
                        get { return (int) ((token & 0xFFFF0000) >> (line_delta_bits + column_bits)); }
                }

                public int Row {
                        get {
                                if (token == 0)
                                        return 1;
                                return checkpoints [CheckpointIndex].LineOffset + ((token & line_delta_mask) >> column_bits);
                        }
                }

                public int Column {
                        get {
                                if (token == 0)
                                        return 1;
                                int col = (int) (token & column_mask);
                                return col == 255 ? 1 : col;
                        }
                }

                public bool Hidden {
                        get {
                                return (int) (token & column_mask) == 255;
                        }
                }

                public int CompilationUnitIndex {
                        get {
                                if (token == 0)
                                        return 0;
if (checkpoints.Length <= CheckpointIndex) throw new Exception (String.Format ("Should not happen. Token is {0:X04}, checkpoints are {1}, index is {2}", token, checkpoints.Length, CheckpointIndex));
                                return checkpoints [CheckpointIndex].CompilationUnit;
                        }
                }

                public int File {
                        get {
                                if (token == 0)
                                        return 0;
if (checkpoints.Length <= CheckpointIndex) throw new Exception (String.Format ("Should not happen. Token is {0:X04}, checkpoints are {1}, index is {2}", token, checkpoints.Length, CheckpointIndex));
                                return checkpoints [CheckpointIndex].File;
                        }
                }

                // The ISymbolDocumentWriter interface is used by the symbol writer to
                // describe a single source file - for each source file there's exactly
                // one corresponding ISymbolDocumentWriter instance.
                //
                // This class has an internal hash table mapping source document names
                // to such ISymbolDocumentWriter instances - so there's exactly one
                // instance per document.
                //
                // This property returns the ISymbolDocumentWriter instance which belongs
                // to the location's source file.
                //
                // If we don't have a symbol writer, this property is always null.
                public SourceFile SourceFile {
                        get {
                                int index = File;
                                if (index == 0)
                                        return null;
                                return (SourceFile) source_list [index - 1];
                        }
                }

                public CompilationUnit CompilationUnit {
                        get {
                                int index = CompilationUnitIndex;
                                if (index == 0)
                                        return null;
                                return (CompilationUnit) source_list [index - 1];
                        }
                }
        }

        public class LocatedToken
        {
                public readonly Location Location;
                public readonly string Value;

                public LocatedToken (Location loc, string value)
                {
                        Location = loc;
                        Value = value;
                }

                public override string ToString ()
                {
                        return Location.ToString () + Value;
                }
        }
}