lldb/source/Host/common/FileSpec.cpp

//===-- FileSpec.cpp --------------------------------------------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//


#ifndef _WIN32
#include <dirent.h>
#else
#include "lldb/Host/windows/windows.h"
#endif
#include <fcntl.h>
#ifndef _MSC_VER
#include <libgen.h>
#endif
#include <sys/stat.h>
#include <set>
#include <string.h>
#include <fstream>

#include "lldb/Host/Config.h" // Have to include this before we test the define...
#ifdef LLDB_CONFIG_TILDE_RESOLVES_TO_USER
#include <pwd.h>
#endif

#include "lldb/Core/DataBufferHeap.h"
#include "lldb/Core/DataBufferMemoryMap.h"
#include "lldb/Core/RegularExpression.h"
#include "lldb/Core/StreamString.h"
#include "lldb/Core/Stream.h"
#include "lldb/Host/File.h"
#include "lldb/Host/FileSpec.h"
#include "lldb/Host/FileSystem.h"
#include "lldb/Host/Host.h"
#include "lldb/Utility/CleanUp.h"

#include "llvm/ADT/StringRef.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/Path.h"
#include "llvm/Support/Program.h"

using namespace lldb;
using namespace lldb_private;

static bool
GetFileStats (const FileSpec *file_spec, struct stat *stats_ptr)
{
    char resolved_path[PATH_MAX];
    if (file_spec->GetPath (resolved_path, sizeof(resolved_path)))
        return ::stat (resolved_path, stats_ptr) == 0;
    return false;
}

// Resolves the username part of a path of the form ~user/other/directories, and
// writes the result into dst_path.  This will also resolve "~" to the current user.
// If you want to complete "~" to the list of users, pass it to ResolvePartialUsername.
void
FileSpec::ResolveUsername (llvm::SmallVectorImpl<char> &path)
{
#if LLDB_CONFIG_TILDE_RESOLVES_TO_USER
    if (path.empty() || path[0] != '~')
        return;
    
    llvm::StringRef path_str(path.data(), path.size());
    size_t slash_pos = path_str.find_first_of("/", 1);
    if (slash_pos == 1 || path.size() == 1)
    {
        // A path of ~/ resolves to the current user's home dir
        llvm::SmallString<64> home_dir;
        if (!llvm::sys::path::home_directory(home_dir))
            return;
        
        // Overwrite the ~ with the first character of the homedir, and insert
        // the rest.  This way we only trigger one move, whereas an insert
        // followed by a delete (or vice versa) would trigger two.
        path[0] = home_dir[0];
        path.insert(path.begin() + 1, home_dir.begin() + 1, home_dir.end());
        return;
    }
    
    auto username_begin = path.begin()+1;
    auto username_end = (slash_pos == llvm::StringRef::npos)
                        ? path.end()
                        : (path.begin() + slash_pos);
    size_t replacement_length = std::distance(path.begin(), username_end);

    llvm::SmallString<20> username(username_begin, username_end);
    struct passwd *user_entry = ::getpwnam(username.c_str());
    if (user_entry != nullptr)
    {
        // Copy over the first n characters of the path, where n is the smaller of the length
        // of the home directory and the slash pos.
        llvm::StringRef homedir(user_entry->pw_dir);
        size_t initial_copy_length = std::min(homedir.size(), replacement_length);
        auto src_begin = homedir.begin();
        auto src_end = src_begin + initial_copy_length;
        std::copy(src_begin, src_end, path.begin());
        if (replacement_length > homedir.size())
        {
            // We copied the entire home directory, but the ~username portion of the path was
            // longer, so there's characters that need to be removed.
            path.erase(path.begin() + initial_copy_length, username_end);
        }
        else if (replacement_length < homedir.size())
        {
            // We copied all the way up to the slash in the destination, but there's still more
            // characters that need to be inserted.
            path.insert(username_end, src_end, homedir.end());
        }
    }
    else
    {
        // Unable to resolve username (user doesn't exist?)
        path.clear();
    }
#endif
}

size_t
FileSpec::ResolvePartialUsername (const char *partial_name, StringList &matches)
{
#ifdef LLDB_CONFIG_TILDE_RESOLVES_TO_USER
    size_t extant_entries = matches.GetSize();
    
    setpwent();
    struct passwd *user_entry;
    const char *name_start = partial_name + 1;
    std::set<std::string> name_list;
    
    while ((user_entry = getpwent()) != NULL)
    {
        if (strstr(user_entry->pw_name, name_start) == user_entry->pw_name)
        {
            std::string tmp_buf("~");
            tmp_buf.append(user_entry->pw_name);
            tmp_buf.push_back('/');
            name_list.insert(tmp_buf);                    
        }
    }
    std::set<std::string>::iterator pos, end = name_list.end();
    for (pos = name_list.begin(); pos != end; pos++)
    {  
        matches.AppendString((*pos).c_str());
    }
    return matches.GetSize() - extant_entries;
#else
    // Resolving home directories is not supported, just copy the path...
    return 0;
#endif // #ifdef LLDB_CONFIG_TILDE_RESOLVES_TO_USER    
}

void
FileSpec::Resolve (llvm::SmallVectorImpl<char> &path)
{
    if (path.empty())
        return;

#ifdef LLDB_CONFIG_TILDE_RESOLVES_TO_USER
    if (path[0] == '~')
        ResolveUsername(path);
#endif // #ifdef LLDB_CONFIG_TILDE_RESOLVES_TO_USER

    llvm::sys::fs::make_absolute(path);
}

FileSpec::FileSpec() : 
    m_directory(), 
    m_filename(), 
    m_syntax(FileSystem::GetNativePathSyntax())
{
}

//------------------------------------------------------------------
// Default constructor that can take an optional full path to a
// file on disk.
//------------------------------------------------------------------
FileSpec::FileSpec(const char *pathname, bool resolve_path, PathSyntax syntax) :
    m_directory(),
    m_filename(),
    m_is_resolved(false),
    m_syntax(syntax)
{
    if (pathname && pathname[0])
        SetFile(pathname, resolve_path, syntax);
}

//------------------------------------------------------------------
// Copy constructor
//------------------------------------------------------------------
FileSpec::FileSpec(const FileSpec& rhs) :
    m_directory (rhs.m_directory),
    m_filename (rhs.m_filename),
    m_is_resolved (rhs.m_is_resolved),
    m_syntax (rhs.m_syntax)
{
}

//------------------------------------------------------------------
// Copy constructor
//------------------------------------------------------------------
FileSpec::FileSpec(const FileSpec* rhs) :
    m_directory(),
    m_filename()
{
    if (rhs)
        *this = *rhs;
}

//------------------------------------------------------------------
// Virtual destructor in case anyone inherits from this class.
//------------------------------------------------------------------
FileSpec::~FileSpec()
{
}

//------------------------------------------------------------------
// Assignment operator.
//------------------------------------------------------------------
const FileSpec&
FileSpec::operator= (const FileSpec& rhs)
{
    if (this != &rhs)
    {
        m_directory = rhs.m_directory;
        m_filename = rhs.m_filename;
        m_is_resolved = rhs.m_is_resolved;
        m_syntax = rhs.m_syntax;
    }
    return *this;
}

void FileSpec::Normalize(llvm::SmallVectorImpl<char> &path, PathSyntax syntax)
{
    if (syntax == ePathSyntaxPosix ||
        (syntax == ePathSyntaxHostNative && FileSystem::GetNativePathSyntax() == ePathSyntaxPosix))
        return;

    std::replace(path.begin(), path.end(), '\\', '/');
    // Windows path can have \\ slashes which can be changed by replace
    // call above to //. Here we remove the duplicate.
    auto iter = std::unique ( path.begin(), path.end(),
                               []( char &c1, char &c2 ){
                                  return (c1 == '/' && c2 == '/');});
    path.erase(iter, path.end());
}

void FileSpec::DeNormalize(llvm::SmallVectorImpl<char> &path, PathSyntax syntax)
{
    if (syntax == ePathSyntaxPosix ||
        (syntax == ePathSyntaxHostNative && FileSystem::GetNativePathSyntax() == ePathSyntaxPosix))
        return;

    std::replace(path.begin(), path.end(), '/', '\\');
}

//------------------------------------------------------------------
// Update the contents of this object with a new path. The path will
// be split up into a directory and filename and stored as uniqued
// string values for quick comparison and efficient memory usage.
//------------------------------------------------------------------
void
FileSpec::SetFile (const char *pathname, bool resolve, PathSyntax syntax)
{
    m_filename.Clear();
    m_directory.Clear();
    m_is_resolved = false;
    m_syntax = (syntax == ePathSyntaxHostNative) ? FileSystem::GetNativePathSyntax() : syntax;

    if (pathname == NULL || pathname[0] == '\0')
        return;

    llvm::SmallString<64> normalized(pathname);

    if (resolve)
    {
        FileSpec::Resolve (normalized);
        m_is_resolved = true;
    }

    // Only normalize after resolving the path.  Resolution will modify the path
    // string, potentially adding wrong kinds of slashes to the path, that need
    // to be re-normalized.
    Normalize(normalized, syntax);

    llvm::StringRef resolve_path_ref(normalized.c_str());
    llvm::StringRef filename_ref = llvm::sys::path::filename(resolve_path_ref);
    if (!filename_ref.empty())
    {
        m_filename.SetString (filename_ref);
        llvm::StringRef directory_ref = llvm::sys::path::parent_path(resolve_path_ref);
        if (!directory_ref.empty())
            m_directory.SetString(directory_ref);
    }
    else
        m_directory.SetCString(normalized.c_str());
}

//----------------------------------------------------------------------
// Convert to pointer operator. This allows code to check any FileSpec
// objects to see if they contain anything valid using code such as:
//
//  if (file_spec)
//  {}
//----------------------------------------------------------------------
FileSpec::operator bool() const
{
    return m_filename || m_directory;
}

//----------------------------------------------------------------------
// Logical NOT operator. This allows code to check any FileSpec
// objects to see if they are invalid using code such as:
//
//  if (!file_spec)
//  {}
//----------------------------------------------------------------------
bool
FileSpec::operator!() const
{
    return !m_directory && !m_filename;
}

//------------------------------------------------------------------
// Equal to operator
//------------------------------------------------------------------
bool
FileSpec::operator== (const FileSpec& rhs) const
{
    if (m_filename == rhs.m_filename)
    {
        if (m_directory == rhs.m_directory)
            return true;
        
        // TODO: determine if we want to keep this code in here.
        // The code below was added to handle a case where we were
        // trying to set a file and line breakpoint and one path
        // was resolved, and the other not and the directory was
        // in a mount point that resolved to a more complete path:
        // "/tmp/a.c" == "/private/tmp/a.c". I might end up pulling
        // this out...
        if (IsResolved() && rhs.IsResolved())
        {
            // Both paths are resolved, no need to look further...
            return false;
        }
        
        FileSpec resolved_lhs(*this);

        // If "this" isn't resolved, resolve it
        if (!IsResolved())
        {
            if (resolved_lhs.ResolvePath())
            {
                // This path wasn't resolved but now it is. Check if the resolved
                // directory is the same as our unresolved directory, and if so, 
                // we can mark this object as resolved to avoid more future resolves
                m_is_resolved = (m_directory == resolved_lhs.m_directory);
            }
            else
                return false;
        }
        
        FileSpec resolved_rhs(rhs);
        if (!rhs.IsResolved())
        {
            if (resolved_rhs.ResolvePath())
            {
                // rhs's path wasn't resolved but now it is. Check if the resolved
                // directory is the same as rhs's unresolved directory, and if so, 
                // we can mark this object as resolved to avoid more future resolves
                rhs.m_is_resolved = (rhs.m_directory == resolved_rhs.m_directory);
            }
            else
                return false;
        }

        // If we reach this point in the code we were able to resolve both paths
        // and since we only resolve the paths if the basenames are equal, then
        // we can just check if both directories are equal...
        return resolved_lhs.GetDirectory() == resolved_rhs.GetDirectory();
    }
    return false;
}

//------------------------------------------------------------------
// Not equal to operator
//------------------------------------------------------------------
bool
FileSpec::operator!= (const FileSpec& rhs) const
{
    return !(*this == rhs);
}

//------------------------------------------------------------------
// Less than operator
//------------------------------------------------------------------
bool
FileSpec::operator< (const FileSpec& rhs) const
{
    return FileSpec::Compare(*this, rhs, true) < 0;
}

//------------------------------------------------------------------
// Dump a FileSpec object to a stream
//------------------------------------------------------------------
Stream&
lldb_private::operator << (Stream &s, const FileSpec& f)
{
    f.Dump(&s);
    return s;
}

//------------------------------------------------------------------
// Clear this object by releasing both the directory and filename
// string values and making them both the empty string.
//------------------------------------------------------------------
void
FileSpec::Clear()
{
    m_directory.Clear();
    m_filename.Clear();
}

//------------------------------------------------------------------
// Compare two FileSpec objects. If "full" is true, then both
// the directory and the filename must match. If "full" is false,
// then the directory names for "a" and "b" are only compared if
// they are both non-empty. This allows a FileSpec object to only
// contain a filename and it can match FileSpec objects that have
// matching filenames with different paths.
//
// Return -1 if the "a" is less than "b", 0 if "a" is equal to "b"
// and "1" if "a" is greater than "b".
//------------------------------------------------------------------
int
FileSpec::Compare(const FileSpec& a, const FileSpec& b, bool full)
{
    int result = 0;

    // If full is true, then we must compare both the directory and filename.

    // If full is false, then if either directory is empty, then we match on
    // the basename only, and if both directories have valid values, we still
    // do a full compare. This allows for matching when we just have a filename
    // in one of the FileSpec objects.

    if (full || (a.m_directory && b.m_directory))
    {
        result = ConstString::Compare(a.m_directory, b.m_directory);
        if (result)
            return result;
    }
    return ConstString::Compare (a.m_filename, b.m_filename);
}

bool
FileSpec::Equal (const FileSpec& a, const FileSpec& b, bool full, bool remove_backups)
{
    if (!full && (a.GetDirectory().IsEmpty() || b.GetDirectory().IsEmpty()))
        return a.m_filename == b.m_filename;
    else if (remove_backups == false)
        return a == b;
    else
    {
        if (a.m_filename != b.m_filename)
            return false;
        if (a.m_directory == b.m_directory)
            return true;
        ConstString a_without_dots;
        ConstString b_without_dots;

        RemoveBackupDots (a.m_directory, a_without_dots);
        RemoveBackupDots (b.m_directory, b_without_dots);
        return a_without_dots == b_without_dots;
    }
}

void
FileSpec::RemoveBackupDots (const ConstString &input_const_str, ConstString &result_const_str)
{
    const char *input = input_const_str.GetCString();
    result_const_str.Clear();
    if (!input || input[0] == '\0')
        return;

    const char win_sep = '\\';
    const char unix_sep = '/';
    char found_sep;
    const char *win_backup = "\\..";
    const char *unix_backup = "/..";

    bool is_win = false;

    // Determine the platform for the path (win or unix):
    
    if (input[0] == win_sep)
        is_win = true;
    else if (input[0] == unix_sep)
        is_win = false;
    else if (input[1] == ':')
        is_win = true;
    else if (strchr(input, unix_sep) != nullptr)
        is_win = false;
    else if (strchr(input, win_sep) != nullptr)
        is_win = true;
    else
    {
        // No separators at all, no reason to do any work here.
        result_const_str = input_const_str;
        return;
    }

    llvm::StringRef backup_sep;
    if (is_win)
    {
        found_sep = win_sep;
        backup_sep = win_backup;
    }
    else
    {
        found_sep = unix_sep;
        backup_sep = unix_backup;
    }
    
    llvm::StringRef input_ref(input);
    llvm::StringRef curpos(input);

    bool had_dots = false;
    std::string result;

    while (1)
    {
        // Start of loop
        llvm::StringRef before_sep;
        std::pair<llvm::StringRef, llvm::StringRef> around_sep = curpos.split(backup_sep);
        
        before_sep = around_sep.first;
        curpos     = around_sep.second;

        if (curpos.empty())
        {
            if (had_dots)
            {
                if (!before_sep.empty())
                {
                    result.append(before_sep.data(), before_sep.size());
                }
            }
            break;
        }
        had_dots = true;

        unsigned num_backups = 1;
        while (curpos.startswith(backup_sep))
        {
            num_backups++;
            curpos = curpos.slice(backup_sep.size(), curpos.size());
        }
        
        size_t end_pos = before_sep.size();
        while (num_backups-- > 0)
        {
            end_pos = before_sep.rfind(found_sep, end_pos);
            if (end_pos == llvm::StringRef::npos)
            {
                result_const_str = input_const_str;
                return;
            }
        }
        result.append(before_sep.data(), end_pos);
    }

    if (had_dots)
        result_const_str.SetCString(result.c_str());
    else
        result_const_str = input_const_str;
        
    return;
}

//------------------------------------------------------------------
// Dump the object to the supplied stream. If the object contains
// a valid directory name, it will be displayed followed by a
// directory delimiter, and the filename.
//------------------------------------------------------------------
void
FileSpec::Dump(Stream *s) const
{
    static ConstString g_slash_only ("/");
    if (s)
    {
        m_directory.Dump(s);
        if (m_directory && m_directory != g_slash_only)
            s->PutChar('/');
        m_filename.Dump(s);
    }
}

//------------------------------------------------------------------
// Returns true if the file exists.
//------------------------------------------------------------------
bool
FileSpec::Exists () const
{
    struct stat file_stats;
    return GetFileStats (this, &file_stats);
}

bool
FileSpec::Readable () const
{
    const uint32_t permissions = GetPermissions();
    if (permissions & eFilePermissionsEveryoneR)
        return true;
    return false;
}

bool
FileSpec::ResolveExecutableLocation ()
{
    if (!m_directory)
    {
        const char *file_cstr = m_filename.GetCString();
        if (file_cstr)
        {
            const std::string file_str (file_cstr);
            llvm::ErrorOr<std::string> error_or_path = llvm::sys::findProgramByName (file_str);
            if (!error_or_path)
                return false;
            std::string path = error_or_path.get();
            llvm::StringRef dir_ref = llvm::sys::path::parent_path(path);
            if (!dir_ref.empty())
            {
                // FindProgramByName returns "." if it can't find the file.
                if (strcmp (".", dir_ref.data()) == 0)
                    return false;

                m_directory.SetCString (dir_ref.data());
                if (Exists())
                    return true;
                else
                {
                    // If FindProgramByName found the file, it returns the directory + filename in its return results.
                    // We need to separate them.
                    FileSpec tmp_file (dir_ref.data(), false);
                    if (tmp_file.Exists())
                    {
                        m_directory = tmp_file.m_directory;
                        return true;
                    }
                }
            }
        }
    }
    
    return false;
}

bool
FileSpec::ResolvePath ()
{
    if (m_is_resolved)
        return true;    // We have already resolved this path

    char path_buf[PATH_MAX];    
    if (!GetPath (path_buf, PATH_MAX, false))
        return false;
    // SetFile(...) will set m_is_resolved correctly if it can resolve the path
    SetFile (path_buf, true);
    return m_is_resolved; 
}

uint64_t
FileSpec::GetByteSize() const
{
    struct stat file_stats;
    if (GetFileStats (this, &file_stats))
        return file_stats.st_size;
    return 0;
}

FileSpec::PathSyntax
FileSpec::GetPathSyntax() const
{
    return m_syntax;
}

FileSpec::FileType
FileSpec::GetFileType () const
{
    struct stat file_stats;
    if (GetFileStats (this, &file_stats))
    {
        mode_t file_type = file_stats.st_mode & S_IFMT;
        switch (file_type)
        {
        case S_IFDIR:   return eFileTypeDirectory;
        case S_IFREG:   return eFileTypeRegular;
#ifndef _WIN32
        case S_IFIFO:   return eFileTypePipe;
        case S_IFSOCK:  return eFileTypeSocket;
        case S_IFLNK:   return eFileTypeSymbolicLink;
#endif
        default:
            break;
        }
        return eFileTypeUnknown;
    }
    return eFileTypeInvalid;
}

uint32_t
FileSpec::GetPermissions () const
{
    uint32_t file_permissions = 0;
    if (*this)
        FileSystem::GetFilePermissions(GetPath().c_str(), file_permissions);
    return file_permissions;
}

TimeValue
FileSpec::GetModificationTime () const
{
    TimeValue mod_time;
    struct stat file_stats;
    if (GetFileStats (this, &file_stats))
        mod_time.OffsetWithSeconds(file_stats.st_mtime);
    return mod_time;
}

//------------------------------------------------------------------
// Directory string get accessor.
//------------------------------------------------------------------
ConstString &
FileSpec::GetDirectory()
{
    return m_directory;
}

//------------------------------------------------------------------
// Directory string const get accessor.
//------------------------------------------------------------------
const ConstString &
FileSpec::GetDirectory() const
{
    return m_directory;
}

//------------------------------------------------------------------
// Filename string get accessor.
//------------------------------------------------------------------
ConstString &
FileSpec::GetFilename()
{
    return m_filename;
}

//------------------------------------------------------------------
// Filename string const get accessor.
//------------------------------------------------------------------
const ConstString &
FileSpec::GetFilename() const
{
    return m_filename;
}

//------------------------------------------------------------------
// Extract the directory and path into a fixed buffer. This is
// needed as the directory and path are stored in separate string
// values.
//------------------------------------------------------------------
size_t
FileSpec::GetPath(char *path, size_t path_max_len, bool denormalize) const
{
    if (!path)
        return 0;

    std::string result = GetPath(denormalize);

    size_t result_length = std::min(path_max_len-1, result.length());
    ::strncpy(path, result.c_str(), result_length + 1);
    return result_length;
}

std::string
FileSpec::GetPath (bool denormalize) const
{
    llvm::SmallString<64> result;
    if (m_directory)
        result.append(m_directory.GetCString());
    if (m_filename)
        llvm::sys::path::append(result, m_filename.GetCString());
    if (denormalize && !result.empty())
        DeNormalize(result, m_syntax);

    return std::string(result.begin(), result.end());
}

ConstString
FileSpec::GetFileNameExtension () const
{
    if (m_filename)
    {
        const char *filename = m_filename.GetCString();
        const char* dot_pos = strrchr(filename, '.');
        if (dot_pos && dot_pos[1] != '\0')
            return ConstString(dot_pos+1);
    }
    return ConstString();
}

ConstString
FileSpec::GetFileNameStrippingExtension () const
{
    const char *filename = m_filename.GetCString();
    if (filename == NULL)
        return ConstString();
    
    const char* dot_pos = strrchr(filename, '.');
    if (dot_pos == NULL)
        return m_filename;
    
    return ConstString(filename, dot_pos-filename);
}

//------------------------------------------------------------------
// Returns a shared pointer to a data buffer that contains all or
// part of the contents of a file. The data is memory mapped and
// will lazily page in data from the file as memory is accessed.
// The data that is mapped will start "file_offset" bytes into the
// file, and "file_size" bytes will be mapped. If "file_size" is
// greater than the number of bytes available in the file starting
// at "file_offset", the number of bytes will be appropriately
// truncated. The final number of bytes that get mapped can be
// verified using the DataBuffer::GetByteSize() function.
//------------------------------------------------------------------
DataBufferSP
FileSpec::MemoryMapFileContents(off_t file_offset, size_t file_size) const
{
    DataBufferSP data_sp;
    std::unique_ptr<DataBufferMemoryMap> mmap_data(new DataBufferMemoryMap());
    if (mmap_data.get())
    {
        const size_t mapped_length = mmap_data->MemoryMapFromFileSpec (this, file_offset, file_size);
        if (((file_size == SIZE_MAX) && (mapped_length > 0)) || (mapped_length >= file_size))
            data_sp.reset(mmap_data.release());
    }
    return data_sp;
}

DataBufferSP
FileSpec::MemoryMapFileContentsIfLocal(off_t file_offset, size_t file_size) const
{
    if (FileSystem::IsLocal(*this))
        return MemoryMapFileContents(file_offset, file_size);
    else
        return ReadFileContents(file_offset, file_size, NULL);
}


//------------------------------------------------------------------
// Return the size in bytes that this object takes in memory. This
// returns the size in bytes of this object, not any shared string
// values it may refer to.
//------------------------------------------------------------------
size_t
FileSpec::MemorySize() const
{
    return m_filename.MemorySize() + m_directory.MemorySize();
}


size_t
FileSpec::ReadFileContents (off_t file_offset, void *dst, size_t dst_len, Error *error_ptr) const
{
    Error error;
    size_t bytes_read = 0;
    char resolved_path[PATH_MAX];
    if (GetPath(resolved_path, sizeof(resolved_path)))
    {
        File file;
        error = file.Open(resolved_path, File::eOpenOptionRead);
        if (error.Success())
        {
            off_t file_offset_after_seek = file_offset;
            bytes_read = dst_len;
            error = file.Read(dst, bytes_read, file_offset_after_seek);
        }
    }
    else
    {
        error.SetErrorString("invalid file specification");
    }
    if (error_ptr)
        *error_ptr = error;
    return bytes_read;
}

//------------------------------------------------------------------
// Returns a shared pointer to a data buffer that contains all or
// part of the contents of a file. The data copies into a heap based
// buffer that lives in the DataBuffer shared pointer object returned.
// The data that is cached will start "file_offset" bytes into the
// file, and "file_size" bytes will be mapped. If "file_size" is
// greater than the number of bytes available in the file starting
// at "file_offset", the number of bytes will be appropriately
// truncated. The final number of bytes that get mapped can be
// verified using the DataBuffer::GetByteSize() function.
//------------------------------------------------------------------
DataBufferSP
FileSpec::ReadFileContents (off_t file_offset, size_t file_size, Error *error_ptr) const
{
    Error error;
    DataBufferSP data_sp;
    char resolved_path[PATH_MAX];
    if (GetPath(resolved_path, sizeof(resolved_path)))
    {
        File file;
        error = file.Open(resolved_path, File::eOpenOptionRead);
        if (error.Success())
        {
            const bool null_terminate = false;
            error = file.Read (file_size, file_offset, null_terminate, data_sp);
        }
    }
    else
    {
        error.SetErrorString("invalid file specification");
    }
    if (error_ptr)
        *error_ptr = error;
    return data_sp;
}

DataBufferSP
FileSpec::ReadFileContentsAsCString(Error *error_ptr)
{
    Error error;
    DataBufferSP data_sp;
    char resolved_path[PATH_MAX];
    if (GetPath(resolved_path, sizeof(resolved_path)))
    {
        File file;
        error = file.Open(resolved_path, File::eOpenOptionRead);
        if (error.Success())
        {
            off_t offset = 0;
            size_t length = SIZE_MAX;
            const bool null_terminate = true;
            error = file.Read (length, offset, null_terminate, data_sp);
        }
    }
    else
    {
        error.SetErrorString("invalid file specification");
    }
    if (error_ptr)
        *error_ptr = error;
    return data_sp;
}

size_t
FileSpec::ReadFileLines (STLStringArray &lines)
{
    lines.clear();
    char path[PATH_MAX];
    if (GetPath(path, sizeof(path)))
    {
        std::ifstream file_stream (path);

        if (file_stream)
        {
            std::string line;
            while (getline (file_stream, line))
                lines.push_back (line);
        }
    }
    return lines.size();
}

FileSpec::EnumerateDirectoryResult
FileSpec::EnumerateDirectory
(
    const char *dir_path, 
    bool find_directories,
    bool find_files,
    bool find_other,
    EnumerateDirectoryCallbackType callback,
    void *callback_baton
)
{
    if (dir_path && dir_path[0])
    {
#if _WIN32
        std::string szDir(dir_path);
        szDir += "\\*";

        WIN32_FIND_DATA ffd;
        HANDLE hFind = FindFirstFile(szDir.c_str(), &ffd);

        if (hFind == INVALID_HANDLE_VALUE)
        {
            return eEnumerateDirectoryResultNext;
        }

        do
        {
            bool call_callback = false;
            FileSpec::FileType file_type = eFileTypeUnknown;
            if (ffd.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)
            {
                size_t len = strlen(ffd.cFileName);

                if (len == 1 && ffd.cFileName[0] == '.')
                    continue;

                if (len == 2 && ffd.cFileName[0] == '.' && ffd.cFileName[1] == '.')
                    continue;

                file_type = eFileTypeDirectory;
                call_callback = find_directories;
            }
            else if (ffd.dwFileAttributes & FILE_ATTRIBUTE_DEVICE)
            {
                file_type = eFileTypeOther;
                call_callback = find_other;
            }
            else
            {
                file_type = eFileTypeRegular;
                call_callback = find_files;
            }
            if (call_callback)
            {
                char child_path[MAX_PATH];
                const int child_path_len = ::snprintf (child_path, sizeof(child_path), "%s\\%s", dir_path, ffd.cFileName);
                if (child_path_len < (int)(sizeof(child_path) - 1))
                {
                    // Don't resolve the file type or path
                    FileSpec child_path_spec (child_path, false);

                    EnumerateDirectoryResult result = callback (callback_baton, file_type, child_path_spec);

                    switch (result)
                    {
                    case eEnumerateDirectoryResultNext:
                        // Enumerate next entry in the current directory. We just
                        // exit this switch and will continue enumerating the
                        // current directory as we currently are...
                        break;

                    case eEnumerateDirectoryResultEnter: // Recurse into the current entry if it is a directory or symlink, or next if not
                        if (FileSpec::EnumerateDirectory(child_path,
                            find_directories,
                            find_files,
                            find_other,
                            callback,
                            callback_baton) == eEnumerateDirectoryResultQuit)
                        {
                            // The subdirectory returned Quit, which means to 
                            // stop all directory enumerations at all levels.
                            return eEnumerateDirectoryResultQuit;
                        }
                        break;

                    case eEnumerateDirectoryResultExit:  // Exit from the current directory at the current level.
                        // Exit from this directory level and tell parent to 
                        // keep enumerating.
                        return eEnumerateDirectoryResultNext;

                    case eEnumerateDirectoryResultQuit:  // Stop directory enumerations at any level
                        return eEnumerateDirectoryResultQuit;
                    }
                }
            }
        } while (FindNextFile(hFind, &ffd) != 0);

        FindClose(hFind);
#else
        lldb_utility::CleanUp <DIR *, int> dir_path_dir(opendir(dir_path), NULL, closedir);
        if (dir_path_dir.is_valid())
        {
            char dir_path_last_char = dir_path[strlen(dir_path) - 1];

            long path_max = fpathconf (dirfd (dir_path_dir.get()), _PC_NAME_MAX);
#if defined (__APPLE_) && defined (__DARWIN_MAXPATHLEN)
            if (path_max < __DARWIN_MAXPATHLEN)
                path_max = __DARWIN_MAXPATHLEN;
#endif
            struct dirent *buf, *dp;
            buf = (struct dirent *) malloc (offsetof (struct dirent, d_name) + path_max + 1);

            while (buf && readdir_r(dir_path_dir.get(), buf, &dp) == 0 && dp)
            {
                // Only search directories
                if (dp->d_type == DT_DIR || dp->d_type == DT_UNKNOWN)
                {
                    size_t len = strlen(dp->d_name);

                    if (len == 1 && dp->d_name[0] == '.')
                        continue;

                    if (len == 2 && dp->d_name[0] == '.' && dp->d_name[1] == '.')
                        continue;
                }
            
                bool call_callback = false;
                FileSpec::FileType file_type = eFileTypeUnknown;

                switch (dp->d_type)
                {
                default:
                case DT_UNKNOWN:    file_type = eFileTypeUnknown;       call_callback = true;               break;
                case DT_FIFO:       file_type = eFileTypePipe;          call_callback = find_other;         break;
                case DT_CHR:        file_type = eFileTypeOther;         call_callback = find_other;         break;
                case DT_DIR:        file_type = eFileTypeDirectory;     call_callback = find_directories;   break;
                case DT_BLK:        file_type = eFileTypeOther;         call_callback = find_other;         break;
                case DT_REG:        file_type = eFileTypeRegular;       call_callback = find_files;         break;
                case DT_LNK:        file_type = eFileTypeSymbolicLink;  call_callback = find_other;         break;
                case DT_SOCK:       file_type = eFileTypeSocket;        call_callback = find_other;         break;
#if !defined(__OpenBSD__)
                case DT_WHT:        file_type = eFileTypeOther;         call_callback = find_other;         break;
#endif
                }

                if (call_callback)
                {
                    char child_path[PATH_MAX];

                    // Don't make paths with "/foo//bar", that just confuses everybody.
                    int child_path_len;
                    if (dir_path_last_char == '/')
                        child_path_len = ::snprintf (child_path, sizeof(child_path), "%s%s", dir_path, dp->d_name);
                    else
                        child_path_len = ::snprintf (child_path, sizeof(child_path), "%s/%s", dir_path, dp->d_name);

                    if (child_path_len < (int)(sizeof(child_path) - 1))
                    {
                        // Don't resolve the file type or path
                        FileSpec child_path_spec (child_path, false);

                        EnumerateDirectoryResult result = callback (callback_baton, file_type, child_path_spec);
                        
                        switch (result)
                        {
                        case eEnumerateDirectoryResultNext:  
                            // Enumerate next entry in the current directory. We just
                            // exit this switch and will continue enumerating the
                            // current directory as we currently are...
                            break;

                        case eEnumerateDirectoryResultEnter: // Recurse into the current entry if it is a directory or symlink, or next if not
                            if (FileSpec::EnumerateDirectory (child_path, 
                                                              find_directories, 
                                                              find_files, 
                                                              find_other, 
                                                              callback, 
                                                              callback_baton) == eEnumerateDirectoryResultQuit)
                            {
                                // The subdirectory returned Quit, which means to 
                                // stop all directory enumerations at all levels.
                                if (buf)
                                    free (buf);
                                return eEnumerateDirectoryResultQuit;
                            }
                            break;
                        
                        case eEnumerateDirectoryResultExit:  // Exit from the current directory at the current level.
                            // Exit from this directory level and tell parent to 
                            // keep enumerating.
                            if (buf)
                                free (buf);
                            return eEnumerateDirectoryResultNext;

                        case eEnumerateDirectoryResultQuit:  // Stop directory enumerations at any level
                            if (buf)
                                free (buf);
                            return eEnumerateDirectoryResultQuit;
                        }
                    }
                }
            }
            if (buf)
            {
                free (buf);
            }
        }
#endif
    }
    // By default when exiting a directory, we tell the parent enumeration
    // to continue enumerating.
    return eEnumerateDirectoryResultNext;    
}

FileSpec
FileSpec::CopyByAppendingPathComponent (const char *new_path)  const
{
    const bool resolve = false;
    if (m_filename.IsEmpty() && m_directory.IsEmpty())
        return FileSpec(new_path,resolve);
    StreamString stream;
    if (m_filename.IsEmpty())
        stream.Printf("%s/%s",m_directory.GetCString(),new_path);
    else if (m_directory.IsEmpty())
        stream.Printf("%s/%s",m_filename.GetCString(),new_path);
    else
        stream.Printf("%s/%s/%s",m_directory.GetCString(), m_filename.GetCString(),new_path);
    return FileSpec(stream.GetData(),resolve);
}

FileSpec
FileSpec::CopyByRemovingLastPathComponent ()  const
{
    const bool resolve = false;
    if (m_filename.IsEmpty() && m_directory.IsEmpty())
        return FileSpec("",resolve);
    if (m_directory.IsEmpty())
        return FileSpec("",resolve);
    if (m_filename.IsEmpty())
    {
        const char* dir_cstr = m_directory.GetCString();
        const char* last_slash_ptr = ::strrchr(dir_cstr, '/');
        
        // check for obvious cases before doing the full thing
        if (!last_slash_ptr)
            return FileSpec("",resolve);
        if (last_slash_ptr == dir_cstr)
            return FileSpec("/",resolve);
        
        size_t last_slash_pos = last_slash_ptr - dir_cstr+1;
        ConstString new_path(dir_cstr,last_slash_pos);
        return FileSpec(new_path.GetCString(),resolve);
    }
    else
        return FileSpec(m_directory.GetCString(),resolve);
}

ConstString
FileSpec::GetLastPathComponent () const
{
    if (m_filename)
        return m_filename;
    if (m_directory)
    {
        const char* dir_cstr = m_directory.GetCString();
        const char* last_slash_ptr = ::strrchr(dir_cstr, '/');
        if (last_slash_ptr == NULL)
            return m_directory;
        if (last_slash_ptr == dir_cstr)
        {
            if (last_slash_ptr[1] == 0)
                return ConstString(last_slash_ptr);
            else
                return ConstString(last_slash_ptr+1);
        }
        if (last_slash_ptr[1] != 0)
            return ConstString(last_slash_ptr+1);
        const char* penultimate_slash_ptr = last_slash_ptr;
        while (*penultimate_slash_ptr)
        {
            --penultimate_slash_ptr;
            if (penultimate_slash_ptr == dir_cstr)
                break;
            if (*penultimate_slash_ptr == '/')
                break;
        }
        ConstString result(penultimate_slash_ptr+1,last_slash_ptr-penultimate_slash_ptr);
        return result;
    }
    return ConstString();
}

void
FileSpec::AppendPathComponent (const char *new_path)
{
    const bool resolve = false;
    if (m_filename.IsEmpty() && m_directory.IsEmpty())
    {
        SetFile(new_path,resolve);
        return;
    }
    StreamString stream;
    if (m_filename.IsEmpty())
        stream.Printf("%s/%s",m_directory.GetCString(),new_path);
    else if (m_directory.IsEmpty())
        stream.Printf("%s/%s",m_filename.GetCString(),new_path);
    else
        stream.Printf("%s/%s/%s",m_directory.GetCString(), m_filename.GetCString(),new_path);
    SetFile(stream.GetData(), resolve);
}

void
FileSpec::RemoveLastPathComponent ()
{
    const bool resolve = false;
    if (m_filename.IsEmpty() && m_directory.IsEmpty())
    {
        SetFile("",resolve);
        return;
    }
    if (m_directory.IsEmpty())
    {
        SetFile("",resolve);
        return;
    }
    if (m_filename.IsEmpty())
    {
        const char* dir_cstr = m_directory.GetCString();
        const char* last_slash_ptr = ::strrchr(dir_cstr, '/');
        
        // check for obvious cases before doing the full thing
        if (!last_slash_ptr)
        {
            SetFile("",resolve);
            return;
        }
        if (last_slash_ptr == dir_cstr)
        {
            SetFile("/",resolve);
            return;
        }        
        size_t last_slash_pos = last_slash_ptr - dir_cstr+1;
        ConstString new_path(dir_cstr,last_slash_pos);
        SetFile(new_path.GetCString(),resolve);
    }
    else
        SetFile(m_directory.GetCString(),resolve);
}
//------------------------------------------------------------------
/// Returns true if the filespec represents an implementation source
/// file (files with a ".c", ".cpp", ".m", ".mm" (many more)
/// extension).
///
/// @return
///     \b true if the filespec represents an implementation source
///     file, \b false otherwise.
//------------------------------------------------------------------
bool
FileSpec::IsSourceImplementationFile () const
{
    ConstString extension (GetFileNameExtension());
    if (extension)
    {
        static RegularExpression g_source_file_regex ("^([cC]|[mM]|[mM][mM]|[cC][pP][pP]|[cC]\\+\\+|[cC][xX][xX]|[cC][cC]|[cC][pP]|[sS]|[aA][sS][mM]|[fF]|[fF]77|[fF]90|[fF]95|[fF]03|[fF][oO][rR]|[fF][tT][nN]|[fF][pP][pP]|[aA][dD][aA]|[aA][dD][bB]|[aA][dD][sS])$");
        return g_source_file_regex.Execute (extension.GetCString());
    }
    return false;
}

bool
FileSpec::IsRelativeToCurrentWorkingDirectory () const
{
    const char *dir = m_directory.GetCString();
    llvm::StringRef directory(dir ? dir : "");

    if (directory.size() > 0)
    {
        if (m_syntax == ePathSyntaxWindows)
        {
            if (directory.size() >= 2 && directory[1] == ':')
                return false;
            if (directory[0] == '/')
                return false;
            return true;
        }
        else
        {
            // If the path doesn't start with '/' or '~', return true
            switch (directory[0])
            {
                case '/':
                case '~':
                    return false;
                default:
                    return true;
            }
        }
    }
    else if (m_filename)
    {
        // No directory, just a basename, return true
        return true;
    }
    return false;
}