kc3-lang/libxkbcommon/src/scanner-utils.h

Branch : - branch - android master - tag -

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  Commit

• Author : Pierre Le Marre
  Date : 2025-06-06 18:40:29
  Hash : 39b4b670
  Message : Support including keymap components using %-expansion and absolute path Enable to use the same `include` features than *rules* files in *keymap components*: - *`%`-expansion*: `%H` home directory, `%S` sytem root and `%E` extra. - absolute file paths. This is useful if one wants to overwrite the system file with a user config (i.e. same name, but in `~/.config/xkb`), but still include the system file: ``` // File: ~/.config/xkb/symbols/de xkb_symbols "basic" { include "%S/de(basic)" key <AB01> { [z, Z] }; key <AD06> { [y, Y] }; } ```` Without the commit, using a mere `include "de(basic)"` would result in an include loop. Refactored by using the same code for rules and keymap components.

• src/scanner-utils.h

• /*
   * Copyright © 2012 Ran Benita <ran234@gmail.com>
   * SPDX-License-Identifier: MIT
   */
  #pragma once
  
  #include "config.h"
  
  #include <stdbool.h>
  #include <stddef.h>
  #include <stdint.h>
  #include <string.h>
  
  #include "context.h"
  #include "darray.h"
  #include "messages-codes.h"
  #include "utils.h"
  #include "utils-numbers.h"
  #include "utf8.h"
  
  /* Point to some substring in the file; used to avoid copying. */
  struct sval {
      const char *start;
      size_t len;
  };
  typedef darray(struct sval) darray_sval;
  
  static inline bool
  svaleq(struct sval s1, struct sval s2)
  {
      return s1.len == s2.len && memcmp(s1.start, s2.start, s1.len) == 0;
  }
  
  static inline bool
  isvaleq(struct sval s1, struct sval s2)
  {
      return s1.len == s2.len && istrncmp(s1.start, s2.start, s1.len) == 0;
  }
  
  static inline bool
  svaleq_prefix(struct sval s1, struct sval s2)
  {
      return s1.len <= s2.len && memcmp(s1.start, s2.start, s1.len) == 0;
  }
  
  #define SVAL(start, len) (struct sval){(start), len}
  #define SVAL_LIT(literal) SVAL(literal, sizeof(literal) - 1)
  #define SVAL_INIT(literal) { literal, sizeof(literal) - 1 }
  
  /* A line:column location in the input string (1-based). */
  struct scanner_loc {
      size_t line, column;
  };
  
  struct scanner {
      const char *s;
      size_t pos;
      size_t len;
      /*
       * Internal buffer.
       * Since this is used to handle paths that are possibly absolute, in theory
       * we should size it to PATH_MAX. However it is very unlikely to reach such
       * long paths in our context.
       */
      char buf[1024];
      size_t buf_pos;
      /* The position of the start of the current token. */
      size_t token_pos;
      /* Cached values used by scanner_token_location. */
      size_t cached_pos;
      struct scanner_loc cached_loc;
      const char *file_name;
      struct xkb_context *ctx;
      void *priv;
  };
  
  /* Compute the line:column location for the current token (slow). */
  struct scanner_loc
  scanner_token_location(struct scanner *s);
  
  #define scanner_log_with_code(scanner, level, verbosity, log_msg_id, fmt, ...) do { \
      struct scanner_loc loc = scanner_token_location((scanner));                     \
      xkb_log_with_code((scanner)->ctx, (level), verbosity, log_msg_id,               \
                        "%s:%zu:%zu: " fmt "\n",                                      \
                        (scanner)->file_name,                                         \
                        loc.line,                                                     \
                        loc.column, ##__VA_ARGS__);                                   \
  } while(0)
  
  #define scanner_err(scanner, id, fmt, ...)                     \
      scanner_log_with_code(scanner, XKB_LOG_LEVEL_ERROR, 0, id, \
                            fmt, ##__VA_ARGS__)
  
  #define scanner_warn(scanner, id, fmt, ...)                      \
      scanner_log_with_code(scanner, XKB_LOG_LEVEL_WARNING, 0, id, \
                            fmt, ##__VA_ARGS__)
  
  #define scanner_vrb(scanner, verbosity, id, fmt, ...)                    \
      scanner_log_with_code(scanner, XKB_LOG_LEVEL_WARNING, verbosity, id, \
                            fmt, ##__VA_ARGS__)
  
  static inline void
  scanner_init(struct scanner *s, struct xkb_context *ctx,
               const char *string, size_t len, const char *file_name,
               void *priv)
  {
      s->s = string;
      s->len = len;
      s->pos = 0;
      s->token_pos = 0;
      s->cached_pos = 0;
      s->cached_loc.line = s->cached_loc.column = 1;
      s->file_name = file_name;
      s->ctx = ctx;
      s->priv = priv;
  }
  
  static inline char
  scanner_peek(struct scanner *s)
  {
      if (unlikely(s->pos >= s->len))
          return '\0';
      return s->s[s->pos];
  }
  
  static inline bool
  scanner_eof(struct scanner *s)
  {
      return s->pos >= s->len;
  }
  
  static inline bool
  scanner_eol(struct scanner *s)
  {
      return scanner_peek(s) == '\n';
  }
  
  static inline void
  scanner_skip_to_eol(struct scanner *s)
  {
      const char *nl = memchr(s->s + s->pos, '\n', s->len - s->pos);
      const size_t new_pos = nl ? (size_t) (nl - s->s) : s->len;
      s->pos = new_pos;
  }
  
  static inline char
  scanner_next(struct scanner *s)
  {
      if (unlikely(scanner_eof(s)))
          return '\0';
      return s->s[s->pos++];
  }
  
  static inline bool
  scanner_chr(struct scanner *s, char ch)
  {
      if (likely(scanner_peek(s) != ch))
          return false;
      s->pos++;
      return true;
  }
  
  static inline bool
  scanner_str(struct scanner *s, const char *string, size_t len)
  {
      if (s->len - s->pos < len)
          return false;
      if (memcmp(s->s + s->pos, string, len) != 0)
          return false;
      s->pos += len;
      return true;
  }
  
  #define scanner_lit(s, literal) scanner_str(s, literal, sizeof(literal) - 1)
  
  static inline bool
  scanner_buf_append(struct scanner *s, char ch)
  {
      if (s->buf_pos + 1 >= sizeof(s->buf))
          return false;
      s->buf[s->buf_pos++] = ch;
      return true;
  }
  
  static inline bool
  scanner_buf_appends(struct scanner *s, const char *str)
  {
      int ret;
      ret = snprintf(s->buf + s->buf_pos, sizeof(s->buf) - s->buf_pos, "%s", str);
      if (ret < 0 || (size_t) ret >= sizeof(s->buf) - s->buf_pos)
          return false;
      s->buf_pos += ret;
      return true;
  }
  
  static inline bool
  scanner_buf_appends_code_point(struct scanner *s, uint32_t c)
  {
      /* Up to 4 bytes + NULL */
      if (s->buf_pos + 5 <= sizeof(s->buf)) {
          int count = utf32_to_utf8(c, s->buf + s->buf_pos);
          if (count == 0) {
              /* Handle encoding failure with U+FFFD REPLACEMENT CHARACTER */
              count = utf32_to_utf8(0xfffd, s->buf + s->buf_pos);
          }
          if (count == 0)
              return false;
          /* `count` counts the NULL byte */
          s->buf_pos += count - 1;
          return true;
      } else {
          return false;
      }
  }
  
  static inline bool
  scanner_oct(struct scanner *s, uint8_t *out)
  {
      uint8_t i = 0;
      uint8_t c = 0;
      for (; scanner_peek(s) >= '0' && scanner_peek(s) <= '7' && i < 4; i++) {
          /* Test overflow */
          if (c < 040) {
              c = c * 8 + scanner_next(s) - '0';
          } else {
              /* Consume valid digit, but mark result as invalid */
              scanner_next(s);
              *out = c;
              return false;
          }
      }
      *out = c;
      return i > 0;
  }
  
  static inline bool
  scanner_hex(struct scanner *s, uint8_t *out)
  {
      uint8_t i;
      for (i = 0, *out = 0; is_xdigit(scanner_peek(s)) && i < 2; i++) {
          const char c = scanner_next(s);
          const char offset = (char) (c >= '0' && c <= '9' ? '0' :
                                      c >= 'a' && c <= 'f' ? 'a' - 10
                                                           : 'A' - 10);
          *out = *out * 16 + c - offset;
      }
      return i > 0;
  }
  
  static inline int
  scanner_dec_int64(struct scanner *s, int64_t *out)
  {
      uint64_t val = 0;
      const int count =
          parse_dec_to_uint64_t(s->s + s->pos, s->len - s->pos, &val);
      if (count > 0) {
          /*
           * NOTE: Since the sign is handled as a token, we parse only *positive*
           *       values here. So that means that *we cannot parse INT64_MIN*,
           *       because abs(INT64_MIN) > INT64_MAX. But we use 64-bit integers
           *       only to avoid under/overflow in expressions: we do not use
           *       64-bit integers in the keymap, only up to 32 bits. So we expect
           *       to parse only 32 bits integers in realistic keymap files and
           *       the limitation should not be an issue.
           */
          if (val > INT64_MAX)
              return -1;
          s->pos += count;
          *out = (int64_t) val;
      }
      return count;
  }
  
  static inline int
  scanner_hex_int64(struct scanner *s, int64_t *out)
  {
      uint64_t val = 0;
      const int count =
          parse_hex_to_uint64_t(s->s + s->pos, s->len - s->pos, &val);
      if (count > 0) {
          /* See comment in `scanner_dec_int64()` above */
          if (val > INT64_MAX)
              return -1;
          s->pos += count;
          *out = (int64_t) val;
      }
      return count;
  }
  
  /** Parser for the {NNNN} part of a Unicode escape sequences */
  static inline bool
  scanner_unicode_code_point(struct scanner *s, uint32_t *out)
  {
      if (!scanner_chr(s, '{'))
          return false;
  
      uint32_t cp = 0;
      const int count =
          parse_hex_to_uint32_t(s->s + s->pos, s->len - s->pos, &cp);
      if (count > 0)
          s->pos += count;
  
      /* Try to consume everything within the string until the next `}` */
      const size_t last_valid = s->pos;
      while (!scanner_eof(s) && !scanner_eol(s) && scanner_peek(s) != '"' &&
             scanner_peek(s) != '}') {
          scanner_next(s);
      }
  
      if (scanner_chr(s, '}')) {
          /* End of the escape sequence; code point may be invalid */
          *out = cp;
          return (count > 0 && s->pos == last_valid + 1 && cp <= 0x10ffff);
      }
  
      /* No closing `}` within the string: rollback to last valid position */
      s->pos = last_valid;
      return false;
  }
  
  /* Basic detection of wrong character encoding based on the first bytes */
  static inline bool
  scanner_check_supported_char_encoding(struct scanner *scanner)
  {
      /* Skip UTF-8 encoded BOM (U+FEFF)
       * See: https://www.unicode.org/faq/utf_bom.html#bom5 */
      if (scanner_str(scanner, "\xef\xbb\xbf", 3) || scanner->len < 2) {
          /* Assume UTF-8 encoding or trivial short input */
          return true;
      }
  
      /* Early detection of wrong file encoding, e.g. UTF-16 or UTF-32 */
      if (scanner->s[0] == '\0' || scanner->s[1] == '\0') {
          scanner_err(scanner, XKB_ERROR_INVALID_FILE_ENCODING,
                      "unexpected NULL character.");
          return false;
      }
      /* Enforce the first character to be ASCII.
         See the note before the use of this function, that explains the relevant
         parts of the grammars of rules, keymap components and Compose. */
      if (!is_ascii(scanner->s[0])) {
          scanner_err(scanner, XKB_ERROR_INVALID_FILE_ENCODING,
                      "unexpected non-ASCII character.");
          return false;
      }
  
      return true;
  }