termux-packages/packages/command-not-found/command-not-found.c

101 lines
3.5 KiB
C

#include <stdio.h>
#include <string.h>
#include <stdbool.h>
#define STRINGIFY(x) #x
#define TOSTRING(x) STRINGIFY(x)
inline int termux_min3(unsigned int a, unsigned int b, unsigned int c) {
return (a < b ? (a < c ? a : c) : (b < c ? b : c));
}
int termux_levenshtein_distance(char const* restrict s1, char const* restrict s2) {
unsigned int s1len = strlen(s1);
unsigned int s2len = strlen(s2);
unsigned int matrix[s2len+1][s1len+1];
matrix[0][0] = 0;
for (unsigned x = 1; x <= s2len; x++)
matrix[x][0] = matrix[x-1][0] + 1;
for (unsigned y = 1; y <= s1len; y++)
matrix[0][y] = matrix[0][y-1] + 1;
for (unsigned x = 1; x <= s2len; x++)
for (unsigned y = 1; y <= s1len; y++)
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));
return matrix[s2len][s1len];
}
int main(int argc, char** argv) {
if (argc != 2) {
fprintf(stderr, "usage: termux-command-not-found <command>\n");
return 1;
}
char* command_not_found = argv[1];
FILE* commands_file = fopen(TOSTRING(TERMUX_COMMANDS_LISTING), "r");
if (commands_file == NULL) {
perror(TOSTRING(TERMUX_COMMANDS_LISTING));
return 1;
}
int best_distance = -1;
int guesses_at_best_distance = 0;
char current_package[128];
char best_package_guess[128];
char best_command_guess[128];
char* current_line = NULL;
while (true) {
size_t buffer_length = sizeof(current_line);
ssize_t read_bytes = getline(&current_line, &buffer_length, commands_file);
if (read_bytes <= 1) break;
size_t line_length = strlen(current_line);
current_line[line_length-1] = 0;
if (current_line[0] == ' ') { // Binary
char* binary_name = current_line + 1;
int distance = termux_levenshtein_distance(command_not_found, binary_name);
if (distance == 0 && strcmp(command_not_found, binary_name) == 0) {
printf("The program '%s' is currently not installed. You can install it by executing:\n apt install %s\n", binary_name, current_package);
return 0;
} else if (best_distance == distance) {
guesses_at_best_distance++;
} else if (best_distance == -1 || best_distance > distance) {
guesses_at_best_distance = 0;
best_distance = distance;
strncpy(best_command_guess, binary_name, sizeof(best_command_guess));
strncpy(best_package_guess, current_package, sizeof(best_package_guess));
}
} else { // Package
strncpy(current_package, current_line, sizeof(current_package));
}
}
if (best_distance == -1 || best_distance > 3) {
printf("%s: command not found\n", command_not_found);
} else {
printf("No command '%s' found, did you mean:\n", command_not_found);
if (guesses_at_best_distance == 1) {
// Only one suggestion - show it:
printf(" Command '%s' from package '%s'\n", best_command_guess, best_package_guess);
} else {
// Multiple suggestions at the same distance - show them all:
rewind(commands_file);
while (true) {
size_t buffer_length = sizeof(current_line);
ssize_t read_bytes = getline(&current_line, &buffer_length, commands_file);
if (read_bytes <= 1) break;
size_t line_length = strlen(current_line);
current_line[line_length-1] = 0;
if (current_line[0] == ' ') { // Binary
char* binary_name = current_line + 1;
int distance = termux_levenshtein_distance(command_not_found, binary_name);
if (best_distance == distance) {
printf(" Command '%s' from package '%s'\n", binary_name, current_package);
}
} else { // Package
strncpy(current_package, current_line, sizeof(current_package));
}
}
}
}
}