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// import.cc -- Go frontend import declarations.

// Copyright 2009 The Go Authors. All rights reserved.

// Use of this source code is governed by a BSD-style

// license that can be found in the LICENSE file.

#include "go-system.h"

#include "filenames.h"

#include "simple-object.h"

#include "go-c.h"

#include "gogo.h"

#include "lex.h"

#include "types.h"

#include "export.h"

#include "import.h"

#ifndef O_BINARY

#define O_BINARY 0

#endif

// The list of paths we search for import files.

static std::vector<std::string> search_path;

// Add a directory to the search path.  This is called from the option

// handling language hook.

GO_EXTERN_C

void

go_add_search_path(const char* path)

{

  search_path.push_back(std::string(path));

}

// Find import data.  This searches the file system for FILENAME and

// returns a pointer to a Stream object to read the data that it

// exports.  If the file is not found, it returns NULL.

// When FILENAME is not an absolute path and does not start with ./ or

// ../, we use the search path provided by -I and -L options.

// When FILENAME does not exist, we try modifying FILENAME to find the

// file.  We use the first of these which exists:

//   * We append ".gox".

//   * We turn the base of FILENAME into libFILENAME.so.

//   * We turn the base of FILENAME into libFILENAME.a.

//   * We append ".o".

// When using a search path, we apply each of these transformations at

// each entry on the search path before moving on to the next entry.

// If the file exists, but does not contain any Go export data, we

// stop; we do not keep looking for another file with the same name

// later in the search path.

Import::Stream*

Import::open_package(const std::string& filename, Location location)

{

  bool is_local;

  if (IS_ABSOLUTE_PATH(filename))

    is_local = true;

  else if (filename[0] == '.' && IS_DIR_SEPARATOR(filename[1]))

    is_local = true;

  else if (filename[0] == '.'

           && filename[1] == '.'

           && IS_DIR_SEPARATOR(filename[2]))

    is_local = true;

  else

    is_local = false;

  if (!is_local)

    {

      for (std::vector<std::string>::const_iterator p = search_path.begin();

           p != search_path.end();

           ++p)

        {

          std::string indir = *p;

          if (!indir.empty() && indir[indir.size() - 1] != '/')

            indir += '/';

          indir += filename;

          Stream* s = Import::try_package_in_directory(indir, location);

          if (s != NULL)

            return s;

        }

    }

  Stream* s = Import::try_package_in_directory(filename, location);

  if (s != NULL)

    return s;

  return NULL;

}

// Try to find the export data for FILENAME.

Import::Stream*

Import::try_package_in_directory(const std::string& filename,

                                 Location location)

{

  std::string found_filename = filename;

  int fd = open(found_filename.c_str(), O_RDONLY | O_BINARY);

  if (fd >= 0)

    {

      struct stat s;

      if (fstat(fd, &s) >= 0 && S_ISDIR(s.st_mode))

        {

          close(fd);

          fd = -1;

          errno = EISDIR;

        }

    }

  if (fd < 0)

    {

      if (errno != ENOENT && errno != EISDIR)

        warning_at(location, 0, "%s: %m", filename.c_str());

      fd = Import::try_suffixes(&found_filename);

      if (fd < 0)

        return NULL;

    }

  // The export data may not be in this file.

  Stream* s = Import::find_export_data(found_filename, fd, location);

  if (s != NULL)

    return s;

  close(fd);

  error_at(location, "%s exists but does not contain any Go export data",

           found_filename.c_str());

  return NULL;

}

// Given import "*PFILENAME", where *PFILENAME does not exist, try

// various suffixes.  If we find one, set *PFILENAME to the one we

// found.  Return the open file descriptor.

int

Import::try_suffixes(std::string* pfilename)

{

  std::string filename = *pfilename + ".gox";

  int fd = open(filename.c_str(), O_RDONLY | O_BINARY);

  if (fd >= 0)

    {

      *pfilename = filename;

      return fd;

    }

  const char* basename = lbasename(pfilename->c_str());

  size_t basename_pos = basename - pfilename->c_str();

  filename = pfilename->substr(0, basename_pos) + "lib" + basename + ".so";

  fd = open(filename.c_str(), O_RDONLY | O_BINARY);

  if (fd >= 0)

    {

      *pfilename = filename;

      return fd;

    }

  filename = pfilename->substr(0, basename_pos) + "lib" + basename + ".a";

  fd = open(filename.c_str(), O_RDONLY | O_BINARY);

  if (fd >= 0)

    {

      *pfilename = filename;

      return fd;

    }

  filename = *pfilename + ".o";

  fd = open(filename.c_str(), O_RDONLY | O_BINARY);

  if (fd >= 0)

    {

      *pfilename = filename;

      return fd;

    }

  return -1;

}

// Look for export data in the file descriptor FD.

Import::Stream*

Import::find_export_data(const std::string& filename, int fd,

                         Location location)

{

  // See if we can read this as an object file.

  Import::Stream* stream = Import::find_object_export_data(filename, fd, 0,

                                                           location);

  if (stream != NULL)

    return stream;

  const int len = MAX(Export::v1_magic_len, Import::archive_magic_len);

  if (lseek(fd, 0, SEEK_SET) < 0)

    {

      error_at(location, "lseek %s failed: %m", filename.c_str());

      return NULL;

    }

  char buf[len];

  ssize_t c = read(fd, buf, len);

  if (c < len)

    return NULL;

  // Check for a file containing nothing but Go export data.

  if (memcmp(buf, Export::v1_magic, Export::v1_magic_len) == 0)

    return new Stream_from_file(fd);

  // See if we can read this as an archive.

  if (Import::is_archive_magic(buf))

    return Import::find_archive_export_data(filename, fd, location);

  return NULL;

}

// Look for export data in a simple_object.

Import::Stream*

Import::find_object_export_data(const std::string& filename,

                                int fd,

                                off_t offset,

                                Location location)

{

  char *buf;

  size_t len;

  int err;

  const char *errmsg = go_read_export_data(fd, offset, &buf, &len, &err);

  if (errmsg != NULL)

    {

      if (err == 0)

        error_at(location, "%s: %s", filename.c_str(), errmsg);

      else

        error_at(location, "%s: %s: %s", filename.c_str(), errmsg,

                 xstrerror(err));

      return NULL;

    }

  if (buf == NULL)

    return NULL;

  return new Stream_from_buffer(buf, len);

}

// Class Import.

// Construct an Import object.  We make the builtin_types_ vector

// large enough to hold all the builtin types.

Import::Import(Stream* stream, Location location)

  : gogo_(NULL), stream_(stream), location_(location), package_(NULL),

    add_to_globals_(false),

    builtin_types_((- SMALLEST_BUILTIN_CODE) + 1),

    types_()

{

}

// Import the data in the associated stream.

Package*

Import::import(Gogo* gogo, const std::string& local_name,

               bool is_local_name_exported)

{

  // Hold on to the Gogo structure.  Otherwise we need to pass it

  // through all the import functions, because we need it when reading

  // a type.

  this->gogo_ = gogo;

  // A stream of export data can include data from more than one input

  // file.  Here we loop over each input file.

  Stream* stream = this->stream_;

  while (!stream->at_eof() && !stream->saw_error())

    {

      // The vector of types is package specific.

      this->types_.clear();

      stream->require_bytes(this->location_, Export::v1_magic,

                            Export::v1_magic_len);

      this->require_c_string("package ");

      std::string package_name = this->read_identifier();

      this->require_c_string(";\n");

      this->require_c_string("prefix ");

      std::string unique_prefix = this->read_identifier();

      this->require_c_string(";\n");

      this->package_ = gogo->add_imported_package(package_name, local_name,

                                                  is_local_name_exported,

                                                  unique_prefix,

                                                  this->location_,

                                                  &this->add_to_globals_);

      if (this->package_ == NULL)

        {

          stream->set_saw_error();

          return NULL;

        }

      this->require_c_string("priority ");

      std::string priority_string = this->read_identifier();

      int prio;

      if (!this->string_to_int(priority_string, false, &prio))

        return NULL;

      this->package_->set_priority(prio);

      this->require_c_string(";\n");

      while (stream->match_c_string("import"))

        this->read_one_import();

      if (stream->match_c_string("init"))

        this->read_import_init_fns(gogo);

      // Loop over all the input data for this package.

      while (!stream->saw_error())

        {

          if (stream->match_c_string("const "))

            this->import_const();

          else if (stream->match_c_string("type "))

            this->import_type();

          else if (stream->match_c_string("var "))

            this->import_var();

          else if (stream->match_c_string("func "))

            this->import_func(this->package_);

          else if (stream->match_c_string("checksum "))

            break;

          else

            {

              error_at(this->location_,

                       ("error in import data at %d: "

                        "expected %<const%>, %<type%>, %<var%>, "

                        "%<func%>, or %<checksum%>"),

                       stream->pos());

              stream->set_saw_error();

              return NULL;

            }

        }

      // We currently ignore the checksum.  In the future we could

      // store the checksum somewhere in the generated object and then

      // verify that the checksum matches at link time or at dynamic

      // load time.

      this->require_c_string("checksum ");

      stream->advance(Export::v1_checksum_len * 2);

      this->require_c_string(";\n");

    }

  return this->package_;

}

// Read an import line.  We don't actually care about these.

void

Import::read_one_import()

{

  this->require_c_string("import ");

  Stream* stream = this->stream_;

  while (stream->peek_char() != ';')

    stream->advance(1);

  this->require_c_string(";\n");

}

// Read the list of import control functions.

void

Import::read_import_init_fns(Gogo* gogo)

{

  this->require_c_string("init");

  while (!this->match_c_string(";"))

    {

      this->require_c_string(" ");

      std::string package_name = this->read_identifier();

      this->require_c_string(" ");

      std::string init_name = this->read_identifier();

      this->require_c_string(" ");

      std::string prio_string = this->read_identifier();

      int prio;

      if (!this->string_to_int(prio_string, false, &prio))

        return;

      gogo->add_import_init_fn(package_name, init_name, prio);

    }

  this->require_c_string(";\n");

}

// Import a constant.

void

Import::import_const()

{

  std::string name;

  Type* type;

  Expression* expr;

  Named_constant::import_const(this, &name, &type, &expr);

  Typed_identifier tid(name, type, this->location_);

  Named_object* no = this->package_->add_constant(tid, expr);

  if (this->add_to_globals_)

    this->gogo_->add_named_object(no);

}

// Import a type.

void

Import::import_type()

{

  Named_type* type;

  Named_type::import_named_type(this, &type);

  // The named type has been added to the package by the type import

  // process.  Here we need to make it visible to the parser, and it

  // to the global bindings if necessary.

  type->set_is_visible();

  if (this->add_to_globals_)

    this->gogo_->add_named_type(type);

}

// Import a variable.

void

Import::import_var()

{

  std::string name;

  Type* type;

  Variable::import_var(this, &name, &type);

  Variable* var = new Variable(type, NULL, true, false, false,

                               this->location_);

  Named_object* no;

  no = this->package_->add_variable(name, var);

  if (this->add_to_globals_)

    this->gogo_->add_named_object(no);

}

// Import a function into PACKAGE.  PACKAGE is normally

// THIS->PACKAGE_, but it will be different for a method associated

// with a type defined in a different package.

Named_object*

Import::import_func(Package* package)

{

  std::string name;

  Typed_identifier* receiver;

  Typed_identifier_list* parameters;

  Typed_identifier_list* results;

  bool is_varargs;

  Function::import_func(this, &name, &receiver, &parameters, &results,

                        &is_varargs);

  Function_type *fntype = Type::make_function_type(receiver, parameters,

                                                   results, this->location_);

  if (is_varargs)

    fntype->set_is_varargs();

  Location loc = this->location_;

  Named_object* no;

  if (fntype->is_method())

    {

      Type* rtype = receiver->type();

      // We may still be reading the definition of RTYPE, so we have

      // to be careful to avoid calling base or convert.  If RTYPE is

      // a named type or a forward declaration, then we know that it

      // is not a pointer, because we are reading a method on RTYPE

      // and named pointers can't have methods.

      if (rtype->classification() == Type::TYPE_POINTER)

        rtype = rtype->points_to();

      if (rtype->is_error_type())

        return NULL;

      else if (rtype->named_type() != NULL)

        no = rtype->named_type()->add_method_declaration(name, package, fntype,

                                                         loc);

      else if (rtype->forward_declaration_type() != NULL)

        no = rtype->forward_declaration_type()->add_method_declaration(name,

                                                                       package,

                                                                       fntype,

                                                                       loc);

      else

        go_unreachable();

    }

  else

    {

      no = package->add_function_declaration(name, fntype, loc);

      if (this->add_to_globals_)

        this->gogo_->add_named_object(no);

    }

  return no;

}

// Read a type in the import stream.  This records the type by the

// type index.  If the type is named, it registers the name, but marks

// it as invisible.

Type*

Import::read_type()

{

  Stream* stream = this->stream_;

  this->require_c_string("<type ");

  std::string number;

  int c;

  while (true)

    {

      c = stream->get_char();

      if (c != '-' && (c < '0' || c > '9'))

        break;

      number += c;

    }

  int index;

  if (!this->string_to_int(number, true, &index))

    return Type::make_error_type();

  if (c == '>')

    {

      // This type was already defined.

      if (index < 0

          ? (static_cast<size_t>(- index) >= this->builtin_types_.size()

             || this->builtin_types_[- index] == NULL)

          : (static_cast<size_t>(index) >= this->types_.size()

             || this->types_[index] == NULL))

        {

          error_at(this->location_,

                   "error in import data at %d: bad type index %d",

                   stream->pos(), index);

          stream->set_saw_error();

          return Type::make_error_type();

        }

      return index < 0 ? this->builtin_types_[- index] : this->types_[index];

    }

  if (c != ' ')

    {

      if (!stream->saw_error())

        error_at(this->location_,

                 "error in import data at %d: expect %< %> or %<>%>'",

                 stream->pos());

      stream->set_saw_error();

      stream->advance(1);

      return Type::make_error_type();

    }

  if (index <= 0

      || (static_cast<size_t>(index) < this->types_.size()

          && this->types_[index] != NULL))

    {

      error_at(this->location_,

               "error in import data at %d: type index already defined",

               stream->pos());

      stream->set_saw_error();

      return Type::make_error_type();

    }

  if (static_cast<size_t>(index) >= this->types_.size())

    {

      int newsize = std::max(static_cast<size_t>(index) + 1,

                             this->types_.size() * 2);

      this->types_.resize(newsize, NULL);

    }

  if (stream->peek_char() != '"')

    {

      Type* type = Type::import_type(this);

      this->require_c_string(">");

      this->types_[index] = type;

      return type;

    }

  // This type has a name.

  stream->advance(1);

  std::string type_name;

  while ((c = stream->get_char()) != '"')

    type_name += c;

  // If this type is in the current package, the name will be

  // .PREFIX.PACKAGE.NAME or simply NAME with no dots.  Otherwise, a

  // non-hidden symbol will be PREFIX.PACKAGE.NAME and a hidden symbol

  // will be .PREFIX.PACKAGE.NAME.

  std::string package_name;

  std::string unique_prefix;

  if (type_name.find('.') != std::string::npos)

    {

      bool is_hidden = false;

      size_t start = 0;

      if (type_name[0] == '.')

        {

          ++start;

          is_hidden = true;

        }

      size_t dot1 = type_name.find('.', start);

      size_t dot2;

      if (dot1 == std::string::npos)

        dot2 = std::string::npos;

      else

        dot2 = type_name.find('.', dot1 + 1);

      if (dot1 == std::string::npos || dot2 == std::string::npos)

        {

          error_at(this->location_,

                   ("error at import data at %d: missing dot in type name"),

                   stream->pos());

          stream->set_saw_error();

        }

      else

        {

          unique_prefix = type_name.substr(start, dot1 - start);

          package_name = type_name.substr(dot1 + 1, dot2 - (dot1 + 1));

        }

      if (!is_hidden)

        type_name.erase(0, dot2 + 1);

    }

  this->require_c_string(" ");

  // Declare the type in the appropriate package.  If we haven't seen

  // it before, mark it as invisible.  We declare it before we read

  // the actual definition of the type, since the definition may refer

  // to the type itself.

  Package* package;

  if (package_name.empty())

    package = this->package_;

  else

    package = this->gogo_->register_package(package_name, unique_prefix,

                                            Linemap::unknown_location());

  Named_object* no = package->bindings()->lookup(type_name);

  if (no == NULL)

    no = package->add_type_declaration(type_name, this->location_);

  else if (!no->is_type_declaration() && !no->is_type())

    {

      error_at(this->location_, "imported %<%s.%s%> both type and non-type",

               Gogo::message_name(package->name()).c_str(),

               Gogo::message_name(type_name).c_str());

      stream->set_saw_error();