chiark - git - mdw - termux-packages/blob - packages/command-not-found/command-not-found.c

   1 #include <stdio.h>
   2 #include <string.h>
   3 #include <stdbool.h>
   4
   5 #include "commands.h"
   6
   7 static inline int termux_min3(unsigned int a, unsigned int b, unsigned int c) {
   8         return (a < b ? (a < c ? a : c) : (b < c ? b : c));
   9 }
  10
  11 static int termux_levenshtein_distance(char const* restrict s1, char const* restrict s2) {
  12         unsigned int s1len = strlen(s1);
  13         unsigned int s2len = strlen(s2);
  14         unsigned int matrix[s2len+1][s1len+1];
  15         matrix[0][0] = 0;
  16         for (unsigned x = 1; x <= s2len; x++)
  17                 matrix[x][0] = matrix[x-1][0] + 1;
  18         for (unsigned y = 1; y <= s1len; y++)
  19                 matrix[0][y] = matrix[0][y-1] + 1;
  20         for (unsigned x = 1; x <= s2len; x++)
  21                 for (unsigned y = 1; y <= s1len; y++)
  22                         matrix[x][y] = termux_min3(matrix[x-1][y] + 1, matrix[x][y-1] + 1, matrix[x-1][y-1] + (s1[y-1] == s2[x-1] ? 0 : 1));
  23         return matrix[s2len][s1len];
  24 }
  25
  26 int main(int argc, char** argv) {
  27         if (argc != 2) {
  28                 fprintf(stderr, "usage: termux-command-not-found <command>\n");
  29                 return 1;
  30         }
  31         char* command_not_found = argv[1];
  32
  33         int best_distance = -1;
  34         int guesses_at_best_distance = 0;
  35         char current_package[128];
  36         char best_package_guess[128];
  37         char best_command_guess[128];
  38         const int num_commands = sizeof(commands) / sizeof(commands[0]);
  39         for (int i = 0; i < num_commands; i++) {
  40                 char const* current_line = commands[i];
  41                 if (current_line[0] == ' ') { // Binary
  42                         char const* binary_name = current_line + 1;
  43                         int distance = termux_levenshtein_distance(command_not_found, binary_name);
  44                         if (distance == 0 && strcmp(command_not_found, binary_name) == 0) {
  45                                 printf("The program '%s' is not installed. Install it by executing:\n packages install %s\n", binary_name, current_package);
  46                                 return 127;
  47                         } else if (best_distance == distance) {
  48                                 guesses_at_best_distance++;
  49                         } else if (best_distance == -1 || best_distance > distance) {
  50                                 guesses_at_best_distance = 0;
  51                                 best_distance = distance;
  52                                 strncpy(best_command_guess, binary_name, sizeof(best_command_guess));
  53                                 strncpy(best_package_guess, current_package, sizeof(best_package_guess));
  54                         }
  55                 } else { // Package
  56                         strncpy(current_package, current_line, sizeof(current_package));
  57                 }
  58         }
  59
  60         if (best_distance == -1 || best_distance > 3) {
  61                 printf("%s: command not found\n", command_not_found);
  62         } else {
  63                 printf("No command '%s' found, did you mean:\n", command_not_found);
  64                 if (guesses_at_best_distance == 1) {
  65                         // Only one suggestion - show it:
  66                         printf(" Command '%s' from package '%s'\n", best_command_guess, best_package_guess);
  67                 } else {
  68                         // Multiple suggestions at the same distance - show them all:
  69                         for (int i = 0; i < num_commands; i++) {
  70                                 char const* current_line = commands[i];
  71                                 if (current_line[0] == ' ') { // Binary
  72                                         char const* binary_name = current_line + 1;
  73                                         int distance = termux_levenshtein_distance(command_not_found, binary_name);
  74                                         if (best_distance == distance) {
  75                                                 printf(" Command '%s' from package '%s'\n", binary_name, current_package);
  76                                         }
  77                                 } else { // Package
  78                                         strncpy(current_package, current_line, sizeof(current_package));
  79                                 }
  80                         }
  81                 }
  82         }
  83         return 127;
  84 }
  85