feat(expansion) 10291 expansion

src/expansion/expansion.c

@@ -86,10 +86,21 @@ static bool expand_var(char **str, size_t pos, const struct hash_map *vars)
     size_t r = parse_var_name(*str + pos, &var_name);
     if (r > 0 && var_name != NULL)
     {
-        char *value = get_var_or_env(vars, var_name);
-        if (value == NULL)
-            // Undefined variable: expand to empty string
-            value = "";
+        char *value;
+        char rnd_str[10]; // max 5 digits + null terminator
+        if (strcmp(var_name, "RANDOM") == 0)
+        {
+            short rnd = short_random();
+            snprintf(rnd_str, 10, "%d", rnd);
+            value = rnd_str;
+        }
+        else
+        {
+            value = get_var_or_env(vars, var_name);
+            if (value == NULL)
+                // Undefined variable: expand to empty string
+                value = "";
+        }
 
         char *p = insert_into(*str, value, pos, r);
         free(var_name);

src/utils/vars/vars.c

@@ -2,8 +2,11 @@
 #include "vars.h"
 
 #include <stdbool.h>
+#include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <time.h>
+#include <unistd.h>
 
 #include "../hash_map/hash_map.h"
 
@@ -14,6 +17,26 @@ struct hash_map *vars_init(void)
     return hash_map_init(VARS_INITIAL_SIZE);
 }
 
+void vars_default(struct hash_map *vars)
+{
+    set_var_copy(vars, "?", "0");
+    pid_t pid = getpid();
+    char pid_str[20];
+    snprintf(pid_str, sizeof(pid_str), "%d", pid);
+    set_var_copy(vars, "$$", pid_str);
+}
+
+short short_random(void)
+{
+    static bool seeded = false;
+    if (!seeded)
+    {
+        srand((unsigned)time(NULL));
+        seeded = true;
+    }
+    return (short)(rand() & 0x7FFF); // force 16 bits positive
+}
+
 char *get_var(const struct hash_map *vars, const char *key)
 {
     return (char *)hash_map_get(vars, key);

src/utils/vars/vars.h

@@ -10,6 +10,16 @@
  */
 struct hash_map *vars_init(void);
 
+/**
+ * Set default variables.
+ */
+void vars_default(struct hash_map *vars);
+
+/**
+ * Generate a random short integer (16 bits positive [0-32767]).
+ */
+short short_random(void);
+
 /**
  * Get the value of a variable, NULL if not found.
  */
@@ -26,7 +36,8 @@ char *get_var_or_env(const struct hash_map *vars, const char *key);
  * the hash_map and need to be on the heap. Returns true on success, false on
  * failure.
  */
-bool set_var(struct hash_map *vars, const char *key, const char *value);
+bool set_var(struct hash_map *vars, const char *key, const char *value,
+             bool *updated);
 
 /**
  * Same as set_var, but makes copies of key and value so you don't have to worry

tests/unit/expansion/expand.c

@@ -42,7 +42,7 @@ Test(expand, single_quotes_no_expansion)
     cr_assert_str_eq((char *)command2->command->data, "echo $VAR",
                      "Variable should not expand inside single quotes");
     ast_free(&ast);
-    hash_map_free(vars);
+    hash_map_free(&vars);
 }
 
 Test(expand, single_dollar)
@@ -61,7 +61,7 @@ Test(expand, single_dollar)
     cr_assert_str_eq((char *)command2->command->data, "echo $ sign",
                      "Variable should not expand inside single quotes");
     ast_free(&ast);
-    hash_map_free(vars);
+    hash_map_free(&vars);
 }
 
 Test(expand, empty_braces_no_expansion)
@@ -78,7 +78,7 @@ Test(expand, empty_braces_no_expansion)
     struct ast_command *command2 = expand(ast_command, vars);
     cr_assert_null(command2, "Expansion should fail on empty braces");
     ast_free(&ast);
-    hash_map_free(vars);
+    hash_map_free(&vars);
 }
 
 Test(expand, basic_expansion)
@@ -97,7 +97,7 @@ Test(expand, basic_expansion)
     cr_assert_str_eq((char *)command2->command->data, "echo expanded",
                      "Variable should expand correctly");
     ast_free(&ast);
-    hash_map_free(vars);
+    hash_map_free(&vars);
 }
 
 Test(expand, multiple_expansion)
@@ -119,7 +119,7 @@ Test(expand, multiple_expansion)
                      "echo expanded values here",
                      "Multiple variables should expand correctly");
     ast_free(&ast);
-    hash_map_free(vars);
+    hash_map_free(&vars);
 }
 
 Test(expand, env_variable)
@@ -154,7 +154,7 @@ Test(expand, undefined_variable)
     cr_assert_str_eq((char *)command2->command->data, "echo ",
                      "Undefined variable should expand to empty string");
     ast_free(&ast);
-    hash_map_free(vars);
+    hash_map_free(&vars);
 }
 
 Test(expand, nested_expansion)
@@ -174,7 +174,7 @@ Test(expand, nested_expansion)
     cr_assert_str_eq((char *)command2->command->data, "echo expanded",
                      "Nested variable should expand correctly");
     ast_free(&ast);
-    hash_map_free(vars);
+    hash_map_free(&vars);
 }
 
 Test(expand, mixed_quotes_expansion)
@@ -196,7 +196,7 @@ Test(expand, mixed_quotes_expansion)
                      "Variable in double quotes should expand, while variable "
                      "in single quotes should not");
     ast_free(&ast);
-    hash_map_free(vars);
+    hash_map_free(&vars);
 }
 
 Test(expand, adjacent_variables)
@@ -216,5 +216,21 @@ Test(expand, adjacent_variables)
     cr_assert_str_eq((char *)command2->command->data, "echo helloworld",
                      "Adjacent variables should expand correctly");
     ast_free(&ast);
-    hash_map_free(vars);
+    hash_map_free(&vars);
+}
+
+Test(expand, random)
+{
+    char str[] = "$RANDOM";
+    char *str_heap = strdup(str);
+    struct list *list = list_append(NULL, str_heap);
+    struct ast *ast = ast_create_command(list);
+    struct ast_command *ast_command = ast_get_command(ast);
+
+    struct ast_command *command2 = expand(ast_command, NULL);
+    cr_assert_not_null(command2, "Expansion returned NULL");
+    int rnd = atoi((char *)command2->command->data);
+    cr_assert(rnd >= 0 && rnd <= 32767,
+              "RANDOM variable should expand to a value between 0 and 32767");
+    ast_free(&ast);
 }