Re: Fixing a sample from K&R book using cake static analyser

On Mon, 24 Jun 2024 00:25:56 +0100, Ben Bacarisse wrote:

struct nlist *install(const char *name, const char *defn)
{
     struct nlist *node = lookup(name);
     if (node) {
          char *new_defn = strdup(defn);
          if (new_defn) {
               free(node->defn);
               node->defn = new_defn;
               return node;
          }
          else return NULL;
     }
     else {
          struct nlist *new_node = malloc(sizeof *new_node);
          char *new_name = strdup(name), *new_defn = strdup(defn);
          if (new_node && new_name && new_defn) {
               unsigned hashval = hash(name);
               new_node->name = new_name;
               new_node->defn = new_defn;
               new_node->next = hashtab[hashval];
               return hashtab[hashval] = new_node;
          }
          else {
               free(new_defn);
               free(new_name);
               free(new_node);
               return NULL;
          }
     }
}
 
We have four cases:
 
  node with the name found
     new definition allocated new definition not allocated
  node with the name not found
     new node, name and definition all allocated not all of new node,
     name and definition allocated.
 
We can very simply reason about all of these situations.

Too many different paths in the control flow, though. I think it’s a good
idea to minimize that.