feat(expansion): parse_subshell_str and tests

src/expansion/expansion.c

@@ -1,4 +1,6 @@
 #define _POSIX_C_SOURCE 200809L
+#include "expansion.h"
+
 #include <ctype.h>
 #include <stdbool.h>
 #include <stdio.h>
@@ -115,6 +117,40 @@ static bool expand_var(char **str, size_t pos, const struct hash_map *vars)
     return false;
 }
 
+size_t parse_subshell_str(char *str, char **res)
+{
+    size_t i = 1; // skip the '('
+    int paren_count = 1;
+
+    if (str[i] == ')')
+    {
+        // empty subshell
+        *res = NULL;
+        return 0;
+    }
+
+    while (str[i] != 0)
+    {
+        if (str[i] == '(')
+            paren_count++;
+        else if (str[i] == ')')
+        {
+            paren_count--;
+
+            if (paren_count == 0)
+            {
+                *res = strndup(str + 1, i - 1);
+                return i + 1;
+            }
+        }
+        i++;
+    }
+
+    // error: parenthesis not closed
+    *res = NULL;
+    return 0;
+}
+
 bool expand(struct ast_command *command, const struct hash_map *vars)
 {
     if (command == NULL)
@@ -122,34 +158,42 @@ bool expand(struct ast_command *command, const struct hash_map *vars)
 
     char *str;
     size_t len;
-    bool in_quotes;
+    enum quote_state quotes;
     struct list *l = command->command;
 
     while (l != NULL)
     {
-        in_quotes = false;
+        quotes = NO_QUOTE;
         str = (char *)l->data;
         len = strlen(str);
 
         for (size_t i = 0; str[i] != 0; i++)
         {
-            if (str[i] == '\'')
+            if (str[i] == '\'' || str[i] == '\"')
             {
-                // remove single quote
+                if (quotes == NO_QUOTE)
-                in_quotes = !in_quotes;
+                {
+                    quotes = (str[i] == '\'') ? SINGLE_QUOTE : DOUBLE_QUOTE;
+                }
+                else if ((quotes == SINGLE_QUOTE && str[i] == '\'')
+                         || (quotes == DOUBLE_QUOTE && str[i] == '\"'))
+                {
+                    quotes = NO_QUOTE;
+                }
+                else
+                {
+                    // inside the other quote type, do nothing
+                    continue;
+                }
+
+                // remove quote
                 memmove(str + i, str + i + 1, strlen(str + i + 1) + 1);
                 i--;
             }
-            else if (in_quotes)
+            else if (quotes == SINGLE_QUOTE)
             {
                 continue; // do nothing
             }
-            else if (str[i] == '\"')
-            {
-                // remove double quote
-                memmove(str + i, str + i + 1, strlen(str + i + 1) + 1);
-                i--;
-            }
             else if (str[i] == '$' && str[i + 1] != 0 && !isspace(str[i + 1]))
             {
                 // variable expansion
@@ -161,21 +205,20 @@ bool expand(struct ast_command *command, const struct hash_map *vars)
             }
         }
 
-        if (in_quotes)
+        // if (quotes != NO_QUOTE)
-        {
+        // {
-            // error: quote not closed
+        //     // error: quote not closed
-            fprintf(stderr, "Error: quote not closed in string: %s\n", str);
+        //     fprintf(stderr, "Error: quote not closed in string: %s\n", str);
-            return false;
+        //     return false;
-        }
+        // }
 
         if (len != strlen(str))
         {
             char *new_str = realloc(str, strlen(str) + 1);
             if (new_str == NULL)
-            {
                 // error: realloc fail
                 return false;
-            }
+
             l->data = new_str;
         }
 

src/expansion/expansion.h

@@ -7,6 +7,13 @@
 #include "../utils/ast/ast.h"
 #include "../utils/hash_map/hash_map.h"
 
+enum quote_state
+{
+    NO_QUOTE,
+    SINGLE_QUOTE,
+    DOUBLE_QUOTE
+};
+
 /**
  * Parse a variable from a string starting with '$'.
  * @param str The input string starting with '$'. It must start with '$'.
@@ -16,6 +23,15 @@
  */
 size_t parse_var_name(char *str, char **res);
 
+/**
+ * Parse a subshell string enclosed in parentheses.
+ * @param str The input string starting with '('. It must start with '('.
+ * @param res Pointer to a char pointer that will be set to the extracted
+ * subshell string.
+ * @return The number of characters processed in the input string.
+ */
+size_t parse_subshell_str(char *str, char **res);
+
 /**
  * Expand variables in an AST command using the provided variable map.
  * @param command The AST command to expand.

tests/unit/expansion/parse_subshell.c

@@ -0,0 +1,72 @@
+#include <criterion/criterion.h>
+#include <criterion/new/assert.h>
+
+#include "../../../src/expansion/expansion.h"
+
+TestSuite(parse_subshell_str);
+
+Test(parse_subshell_str, basic_subshell)
+{
+    char *input = "(ls -l)";
+    char *extracted_var = NULL;
+    size_t r = parse_subshell_str(input, &extracted_var);
+
+    cr_expect(r == 7);
+    cr_expect_str_eq(extracted_var, "ls -l");
+    free(extracted_var);
+}
+
+Test(parse_subshell_str, multi_basic_subshell)
+{
+    char *input = "(echo hello) and (echo world)";
+    char *extracted_var = NULL;
+    size_t r = parse_subshell_str(input, &extracted_var);
+
+    cr_expect(r == 12);
+    cr_expect_str_eq(extracted_var, "echo hello");
+    free(extracted_var);
+
+    input += r + 5; // skip " and "
+    r = parse_subshell_str(input, &extracted_var);
+
+    cr_expect(r == 12);
+    cr_expect_str_eq(extracted_var, "echo world");
+    free(extracted_var);
+}
+
+Test(parse_subshell_str, incomplete_braces)
+{
+    char *input = "(echo hello";
+    char *extracted_var = NULL;
+    size_t r = parse_subshell_str(input, &extracted_var);
+
+    cr_expect(r == 0);
+    cr_expect(extracted_var == NULL);
+}
+
+Test(parse_subshell_str, empty_braces)
+{
+    char *input = "()";
+    char *extracted_var = NULL;
+    size_t r = parse_subshell_str(input, &extracted_var);
+
+    cr_expect(r == 0);
+    cr_expect(extracted_var == NULL);
+}
+
+Test(parse_subshell_str, nested_subshell)
+{
+    char *input = "(echo (nested))";
+    char *extracted_var = NULL;
+    size_t r = parse_subshell_str(input, &extracted_var);
+
+    cr_expect(r == 15);
+    cr_expect_str_eq(extracted_var, "echo (nested)");
+    free(extracted_var);
+
+    char *nested = input + 6; // point to the nested subshell
+    r = parse_subshell_str(nested, &extracted_var);
+    cr_expect(r == 8);
+    cr_expect_str_eq(extracted_var, "nested");
+    free(extracted_var);
+}

tests/unit/expansion/parse_var.c

@@ -1,6 +1,5 @@
 #include <criterion/criterion.h>
 #include <criterion/new/assert.h>
-#include <criterion/redirect.h>
 
 #include "../../../src/expansion/expansion.h"