From 9f7bf8ddf255f06a3c27c13dad87e34a70356d58 Mon Sep 17 00:00:00 2001 From: Stefan Zabka Date: Wed, 20 May 2020 18:07:43 +0200 Subject: First implementation of prompt --- 02_exercise/prompt_utils.c | 90 +++++++++++++++++++++++++++++++++++++++++ 02_exercise/prompt_utils.h | 11 +++++ 02_exercise/prompt_utils_test.c | 36 +++++++++++++++++ 02_exercise/prompt_utils_test.h | 6 +++ 02_exercise/shell.c | 49 +++++----------------- 5 files changed, 154 insertions(+), 38 deletions(-) create mode 100644 02_exercise/prompt_utils.c create mode 100644 02_exercise/prompt_utils.h create mode 100644 02_exercise/prompt_utils_test.c create mode 100644 02_exercise/prompt_utils_test.h diff --git a/02_exercise/prompt_utils.c b/02_exercise/prompt_utils.c new file mode 100644 index 0000000..819509d --- /dev/null +++ b/02_exercise/prompt_utils.c @@ -0,0 +1,90 @@ +#include "prompt_utils.h" + +#include "array.h" +#include +#include +#include +#include + +char const *const relative_path(char const *const from_dir, char const *const to_dir) { + // easiest cases first + { + int result = strcmp(from_dir, to_dir); + if (result == 0) { + char *return_value = malloc(2); + strcpy(return_value, "."); + return return_value; + } + } + { + if (strcmp("/", from_dir) == 0) { + char *return_value = malloc(strlen(to_dir) + 2); + return_value[0] = '.'; + memcpy(return_value + 1, to_dir, strlen(to_dir) + 1); + return return_value; + } + } + // Splitting path into pieces so we can do strcmp on each of them + size_t const *const from_dir_indeces = get_seperator_indeces(from_dir, '/'); + size_t const *const to_dir_indeces = get_seperator_indeces(to_dir, '/'); + + size_t from_dir_len = arrayLen(from_dir_indeces); + size_t to_dir_len = arrayLen(to_dir_indeces); + + // finding the longest common substring + size_t array_len = from_dir_len < to_dir_len ? from_dir_len : to_dir_len; + size_t i = 0; + size_t common_position = 0; + for (; i < array_len - 1; i++) { + if (from_dir_indeces[i + 1] != to_dir_indeces[i + 1]) { + break; + } + size_t index = from_dir_indeces[i]; + size_t count = from_dir_indeces[i + 1] - from_dir_indeces[i]; + if (strncmp(from_dir + index, to_dir + index, count) != 0) { + break; + } + common_position = from_dir_indeces[i + 1]; + } + + size_t levels_up = from_dir_len - i - 1; + char *return_value; + if (levels_up == 0) { + // Equal dirs for whole length of path and not equal => subdir + size_t length = strlen(to_dir + common_position) + strlen("./") + 1; + return_value = malloc(length * sizeof(char)); + strcpy(return_value, "."); + strcat(return_value, to_dir + common_position); + } else { + char const *const go_up = "/.."; + size_t length = strlen(to_dir + common_position) + strlen("..") + + strlen(go_up) * (levels_up - 1); + return_value = malloc(length * sizeof(char)); + strcpy(return_value, ".."); + for (size_t j = 0; j < levels_up - 1; j++) { + strcat(return_value, go_up); + } + strcat(return_value, to_dir + common_position); + } + + arrayRelease((void *)from_dir_indeces); + arrayRelease((void *)to_dir_indeces); + + return return_value; +} + +size_t *get_seperator_indeces(char const *const text, char seperator) { + size_t *indeces; + arrayInit(indeces); + char const *current = text; + if (strchr(current, seperator) == NULL) { + arrayRelease(indeces); + return NULL; + } + while ((current = strchr(current, seperator)) != NULL) { + arrayPush(indeces) = current - text; + ++current; + } + arrayPush(indeces) = strlen(text); + return indeces; +} diff --git a/02_exercise/prompt_utils.h b/02_exercise/prompt_utils.h new file mode 100644 index 0000000..93de502 --- /dev/null +++ b/02_exercise/prompt_utils.h @@ -0,0 +1,11 @@ +#ifndef PROMPT_UTILS_H_INCLUDED +#define PROMPT_UTILS_H_INCLUDED + +#include + +// Returns the relative path to get from the `from_dir` to the `to_dir` +char const *const relative_path(char const *const from_dir, char const *const to_dir); + +// Returns the position of each element one after the seperator +size_t *get_seperator_indeces(char const *const text, char seperator); +#endif // PROMPT_UTILS_H_INCLUDED \ No newline at end of file diff --git a/02_exercise/prompt_utils_test.c b/02_exercise/prompt_utils_test.c new file mode 100644 index 0000000..b26ce6f --- /dev/null +++ b/02_exercise/prompt_utils_test.c @@ -0,0 +1,36 @@ +#include "array.h" +#include "prompt_utils.h" +#include +#include +#include + +void test_get_seperator_indeces() { + char const *const test_str = "/This/is/a/test"; + size_t const *const result = get_seperator_indeces(test_str, '/'); + for (size_t i = 0; i < arrayLen(result); i++) { + printf("%ld : %s \n", result[i], test_str + result[i]); + } +} +void test_paths(char const *const from, char const *const to, + char const *const expected) { + size_t const *const result = get_seperator_indeces(from, '/'); + for (size_t i = 0; i < arrayLen(result); i++) { + printf("%ld : %s \n", result[i], from + result[i]); + } + size_t const *const result2 = get_seperator_indeces(to, '/'); + for (size_t i = 0; i < arrayLen(result2); i++) { + printf("%ld : %s \n", result2[i], to + result2[i]); + } + char const *const path = relative_path(from, to); + printf("The relative path of %s to %s is %s \n", from, to, path); + + assert(strcmp(path, expected) == 0); +} +void test_relative_path() { + test_paths("/Test", "/Test/a", "./a"); + test_paths("/abc/def/ghi", "/abc/def/ghi", "."); + test_paths("/Test", "/Test/a/asd", "./a/asd"); + test_paths("/Test/b/c", "/Test/b", ".."); + test_paths("/", "/Test/a/asd", "./Test/a/asd"); + test_paths("/Test/c", "/Test/b", "../b"); +} \ No newline at end of file diff --git a/02_exercise/prompt_utils_test.h b/02_exercise/prompt_utils_test.h new file mode 100644 index 0000000..5c637b2 --- /dev/null +++ b/02_exercise/prompt_utils_test.h @@ -0,0 +1,6 @@ +#ifndef PROMPT_UTILS_H_INCLUDED +#define PROMPT_UTILS_H_INCLUDED +void test_get_seperator_indeces(); +void test_relative_path(); + +#endif \ No newline at end of file diff --git a/02_exercise/shell.c b/02_exercise/shell.c index 2594d6b..c0c51e1 100644 --- a/02_exercise/shell.c +++ b/02_exercise/shell.c @@ -2,16 +2,17 @@ #include #include +#include #include #include +#include #include #include #include #include #include "array.h" -#include "errno.h" -#include "stdbool.h" +#include "prompt_utils.h" void print_prompt(char const *const original_wd, char const *current_wd); @@ -19,16 +20,15 @@ void print_prompt(char const *const original_wd, char const *current_wd); int exec_command(char *command); int main(void) { - // the directory is specified without a / at the end char const *const original_wd = get_current_dir_name(); - char const *current_wd = get_current_dir_name(); - + char const *prompt = relative_path(original_wd, original_wd); + printf("%s \n", original_wd); while (true) { char *command = NULL; size_t cap = 0; size_t length = 0; - print_prompt(original_wd, current_wd); + printf("%s > ", prompt); if ((length = getline(&command, &cap, stdin)) < 0) { fprintf(stderr, "Failed to read from STDIN"); exit(-1); @@ -36,8 +36,10 @@ int main(void) { if (strstr(command, "cd") != NULL) { printf("Changing dirs \n"); chdir("beispiele"); - free((void *) current_wd); - current_wd = get_current_dir_name(); + free((void *)prompt); + char const *current_wd = get_current_dir_name(); + prompt = relative_path(original_wd, current_wd); + free((void *)current_wd); } else if (strcmp(command, "exit\n") == 0) { exit(0); } else { @@ -47,36 +49,7 @@ int main(void) { } // Gotta cast to void otherwise we discard qualifiers free((void *)original_wd); - free((void *)current_wd); -} - -void print_prompt(char const *const original_wd, char const *const current_wd) { - // easiest case first - { - int result = strcmp(original_wd, current_wd); - if (result == 0) { - printf(".> "); - return; - } - } - printf("%s > ", current_wd); - // Now checking for substrings aka are we in a subdir - { - size_t dirlen = strlen(original_wd); - char *const orig_dir_with_slash = malloc(dirlen + 2); - if (orig_dir_with_slash == NULL) { - fprintf(stderr, "Failed to allocate for prompt"); - exit(ENOMEM); - } - memcpy(orig_dir_with_slash, original_wd, dirlen); - orig_dir_with_slash[dirlen] = '/'; - orig_dir_with_slash[dirlen + 1] = '\0'; - char const *const result = strstr(current_wd, original_wd); - if (result != NULL) { - printf(".%s > ", current_wd + dirlen); - return; - } - } + free((void *)prompt); } int exec_command(char *command) { return 0; } -- cgit v1.2.3-54-g00ecf