gcc/go/gofrontend/import.h

   1 // import.h -- Go frontend import declarations.     -*- C++ -*-
   2
   3 // Copyright 2009 The Go Authors. All rights reserved.
   4 // Use of this source code is governed by a BSD-style
   5 // license that can be found in the LICENSE file.
   6
   7 #ifndef GO_IMPORT_H
   8 #define GO_IMPORT_H
   9
  10 #include "export.h"
  11 #include "go-linemap.h"
  12
  13 class Gogo;
  14 class Package;
  15 class Type;
  16 class Named_object;
  17 class Named_type;
  18 class Expression;
  19
  20 // This class manages importing Go declarations.
  21
  22 class Import
  23 {
  24  public:
  25   // The Stream class is an interface used to read the data.  The
  26   // caller should instantiate a child of this class.
  27   class Stream
  28   {
  29    public:
  30     Stream();
  31     virtual ~Stream();
  32
  33     // Return whether we have seen an error.
  34     bool
  35     saw_error() const
  36     { return this->saw_error_; }
  37
  38     // Record that we've seen an error.
  39     void
  40     set_saw_error()
  41     { this->saw_error_ = true; }
  42
  43     // Return the next character (a value from 0 to 0xff) without
  44     // advancing.  Returns -1 at end of stream.
  45     int
  46     peek_char();
  47
  48     // Look for LENGTH characters, setting *BYTES to point to them.
  49     // Returns false if the bytes are not available.  Does not
  50     // advance.
  51     bool
  52     peek(size_t length, const char** bytes)
  53     { return this->do_peek(length, bytes); }
  54
  55     // Return the next character (a value from 0 to 0xff) and advance
  56     // the read position by 1.  Returns -1 at end of stream.
  57     int
  58     get_char()
  59     {
  60       int c = this->peek_char();
  61       this->advance(1);
  62       return c;
  63     }
  64
  65     // Return true if at the end of the stream.
  66     bool
  67     at_eof()
  68     { return this->peek_char() == -1; }
  69
  70     // Return true if the next bytes match STR.
  71     bool
  72     match_c_string(const char* str)
  73     { return this->match_bytes(str, strlen(str)); }
  74
  75     // Return true if the next LENGTH bytes match BYTES.
  76     bool
  77     match_bytes(const char* bytes, size_t length);
  78
  79     // Give an error if the next bytes do not match STR.  Advance the
  80     // read position by the length of STR.
  81     void
  82     require_c_string(Location location, const char* str)
  83     { this->require_bytes(location, str, strlen(str)); }
  84
  85     // Given an error if the next LENGTH bytes do not match BYTES.
  86     // Advance the read position by LENGTH.
  87     void
  88     require_bytes(Location, const char* bytes, size_t length);
  89
  90     // Advance the read position by SKIP bytes.
  91     void
  92     advance(size_t skip)
  93     {
  94       this->do_advance(skip);
  95       this->pos_ += skip;
  96     }
  97
  98     // Return the current read position.  This returns int because it
  99     // is more convenient in error reporting.  FIXME.
 100     int
 101     pos()
 102     { return static_cast<int>(this->pos_); }
 103
 104    protected:
 105     // This function should set *BYTES to point to a buffer holding
 106     // the LENGTH bytes at the current read position.  It should
 107     // return false if the bytes are not available.  This should not
 108     // change the current read position.
 109     virtual bool
 110     do_peek(size_t length, const char** bytes) = 0;
 111
 112     // This function should advance the current read position LENGTH
 113     // bytes.
 114     virtual void
 115     do_advance(size_t skip) = 0;
 116
 117    private:
 118     // The current read position.
 119     size_t pos_;
 120     // True if we've seen an error reading from this stream.
 121     bool saw_error_;
 122   };
 123
 124   // Find import data.  This searches the file system for FILENAME and
 125   // returns a pointer to a Stream object to read the data that it
 126   // exports.  LOCATION is the location of the import statement.
 127   // RELATIVE_IMPORT_PATH is used as a prefix for a relative import.
 128   static Stream*
 129   open_package(const std::string& filename, Location location,
 130                const std::string& relative_import_path);
 131
 132   // Constructor.
 133   Import(Stream*, Location);
 134
 135   // Register the builtin types.
 136   void
 137   register_builtin_types(Gogo*);
 138
 139   // Import everything defined in the stream.  LOCAL_NAME is the local
 140   // name to be used for bindings; if it is the string "." then
 141   // bindings should be inserted in the global scope.  If LOCAL_NAME
 142   // is the empty string then the name of the package itself is the
 143   // local name.  This returns the imported package, or NULL on error.
 144   Package*
 145   import(Gogo*, const std::string& local_name, bool is_local_name_exported);
 146
 147   // The location of the import statement.
 148   Location
 149   location() const
 150   { return this->location_; }
 151
 152   // Return the package we are importing.
 153   Package*
 154   package() const
 155   { return this->package_; }
 156
 157   // Return the next character.
 158   int
 159   peek_char()
 160   { return this->stream_->peek_char(); }
 161
 162   // Return the next character and advance.
 163   int
 164   get_char()
 165   { return this->stream_->get_char(); }
 166
 167   // Return true at the end of the stream.
 168   bool
 169   at_eof()
 170   { return this->stream_->at_eof(); }
 171
 172   // Return whether the next bytes match STR.
 173   bool
 174   match_c_string(const char* str)
 175   { return this->stream_->match_c_string(str); }
 176
 177   // Require that the next bytes match STR.
 178   void
 179   require_c_string(const char* str)
 180   { this->stream_->require_c_string(this->location_, str); }
 181
 182   // Advance the stream SKIP bytes.
 183   void
 184   advance(size_t skip)
 185   { this->stream_->advance(skip); }
 186
 187   // Read an identifier.
 188   std::string
 189   read_identifier();
 190
 191   // Read a name.  This is like read_identifier, except that a "?" is
 192   // returned as an empty string.  This matches Export::write_name.
 193   std::string
 194   read_name();
 195
 196   // Read a type.
 197   Type*
 198   read_type();
 199
 200  private:
 201   static Stream*
 202   try_package_in_directory(const std::string&, Location);
 203
 204   static int
 205   try_suffixes(std::string*);
 206
 207   static Stream*
 208   find_export_data(const std::string& filename, int fd, Location);
 209
 210   static Stream*
 211   find_object_export_data(const std::string& filename, int fd,
 212                           off_t offset, Location);
 213
 214   static const int archive_magic_len = 8;
 215
 216   static bool
 217   is_archive_magic(const char*);
 218
 219   static Stream*
 220   find_archive_export_data(const std::string& filename, int fd,
 221                            Location);
 222
 223   // Read an import line.
 224   void
 225   read_one_import();
 226
 227   // Read the import control functions.
 228   void
 229   read_import_init_fns(Gogo*);
 230
 231   // Import a constant.
 232   void
 233   import_const();
 234
 235   // Import a type.
 236   void
 237   import_type();
 238
 239   // Import a variable.
 240   void
 241   import_var();
 242
 243   // Import a function.
 244   Named_object*
 245   import_func(Package*);
 246
 247   // Register a single builtin type.
 248   void
 249   register_builtin_type(Gogo*, const char* name, Builtin_code);
 250
 251   // Get an integer from a string.
 252   bool
 253   string_to_int(const std::string&, bool is_neg_ok, int* ret);
 254
 255   // The general IR.
 256   Gogo* gogo_;
 257   // The stream from which to read import data.
 258   Stream* stream_;
 259   // The location of the import statement we are processing.
 260   Location location_;
 261   // The package we are importing.
 262   Package* package_;
 263   // Whether to add new objects to the global scope, rather than to a
 264   // package scope.
 265   bool add_to_globals_;
 266   // Mapping from negated builtin type codes to Type structures.
 267   std::vector<Named_type*> builtin_types_;
 268   // Mapping from exported type codes to Type structures.
 269   std::vector<Type*> types_;
 270 };
 271
 272 // Read import data from a string.
 273
 274 class Stream_from_string : public Import::Stream
 275 {
 276  public:
 277   Stream_from_string(const std::string& str)
 278     : str_(str), pos_(0)
 279   { }
 280
 281  protected:
 282   bool
 283   do_peek(size_t length, const char** bytes)
 284   {
 285     if (this->pos_ + length > this->str_.length())
 286       return false;
 287     *bytes = this->str_.data() + this->pos_;
 288     return true;
 289   }
 290
 291   void
 292   do_advance(size_t len)
 293   { this->pos_ += len; }
 294
 295  private:
 296   // The string of data we are reading.
 297   std::string str_;
 298   // The current position within the string.
 299   size_t pos_;
 300 };
 301
 302 // Read import data from a buffer allocated using malloc.
 303
 304 class Stream_from_buffer : public Import::Stream
 305 {
 306  public:
 307   Stream_from_buffer(char* buf, size_t length)
 308     : buf_(buf), length_(length), pos_(0)
 309   { }
 310
 311   ~Stream_from_buffer()
 312   { free(this->buf_); }
 313
 314  protected:
 315   bool
 316   do_peek(size_t length, const char** bytes)
 317   {
 318     if (this->pos_ + length > this->length_)
 319       return false;
 320     *bytes = this->buf_ + this->pos_;
 321     return true;
 322   }
 323
 324   void
 325   do_advance(size_t len)
 326   { this->pos_ += len; }
 327
 328  private:
 329   // The data we are reading.
 330   char* buf_;
 331   // The length of the buffer.
 332   size_t length_;
 333   // The current position within the buffer.
 334   size_t pos_;
 335 };
 336
 337 // Read import data from an open file descriptor.
 338
 339 class Stream_from_file : public Import::Stream
 340 {
 341  public:
 342   Stream_from_file(int fd);
 343
 344   ~Stream_from_file();
 345
 346  protected:
 347   bool
 348   do_peek(size_t, const char**);
 349
 350   void
 351   do_advance(size_t);
 352
 353  private:
 354   // No copying.
 355   Stream_from_file(const Stream_from_file&);
 356   Stream_from_file& operator=(const Stream_from_file&);
 357
 358   // The file descriptor.
 359   int fd_;
 360   // Data read from the file.
 361   std::string data_;
 362 };
 363
 364 #endif // !defined(GO_IMPORT_H)