Rewrite parse_util_unescape_wildcards

Make it simpler, and use wcstring instead of wcsdup

src/complete.cpp

@@ -935,7 +935,7 @@ void completer_t::complete_strings(const wcstring &wc_escaped,
     if (! expand_one(tmp, EXPAND_SKIP_CMDSUBST | EXPAND_SKIP_WILDCARDS | this->expand_flags(), NULL))
         return;
 
-    const wchar_t *wc = parse_util_unescape_wildcards(tmp.c_str());
+    const wcstring wc = parse_util_unescape_wildcards(tmp);
 
     for (size_t i=0; i< possible_comp.size(); i++)
     {
@@ -944,11 +944,9 @@ void completer_t::complete_strings(const wcstring &wc_escaped,
 
         if (next_str)
         {
-            wildcard_complete(next_str, wc, desc, desc_func, &this->completions, this->expand_flags(), flags);
+            wildcard_complete(next_str, wc.c_str(), desc, desc_func, &this->completions, this->expand_flags(), flags);
         }
     }
-
-    free((void *)wc);
 }
 
 /**

src/parse_execution.cpp

@@ -613,9 +613,8 @@ parse_execution_result_t parse_execution_context_t::run_switch_statement(const p
                     const wcstring &arg = case_args.at(i);
 
                     /* Unescape wildcards so they can be expanded again */
-                    wchar_t *unescaped_arg = parse_util_unescape_wildcards(arg.c_str());
+                    wcstring unescaped_arg = parse_util_unescape_wildcards(arg);
                     bool match = wildcard_match(switch_value_expanded, unescaped_arg);
-                    free(unescaped_arg);
 
                     /* If this matched, we're done */
                     if (match)

src/parse_tree.cpp

@@ -325,7 +325,7 @@ static wcstring block_type_user_presentable_description(parse_token_type_t type)
 }
 
 /** Returns a string description of the given parse node */
-wcstring parse_node_t::describe(void) const
+wcstring parse_node_t::describe() const
 {
     wcstring result = token_type_description(type);
     if (type < FIRST_TERMINAL_TYPE)

src/parse_util.cpp

@@ -561,75 +561,42 @@ void parse_util_token_extent(const wchar_t *buff,
 
 }
 
-wchar_t *parse_util_unescape_wildcards(const wchar_t *str)
+wcstring parse_util_unescape_wildcards(const wcstring &str)
 {
-    wchar_t *in, *out;
-    wchar_t *unescaped;
-
-    CHECK(str, 0);
-
-    unescaped = wcsdup(str);
-
-    if (!unescaped)
+    wcstring result;
+    result.reserve(str.size());
+    
+    const wchar_t * const cs = str.c_str();
+    for (size_t i=0; cs[i] != L'\0'; i++)
     {
-        DIE_MEM();
-    }
-
-    for (in=out=unescaped; *in; in++)
-    {
-        switch (*in)
+        if (cs[i] == L'*')
         {
-            case L'\\':
-            {
-                switch (*(in + 1))
-                {
-                    case L'*':
-                    case L'?':
-                    {
-                        in++;
-                        *(out++)=*in;
-                        break;
-                    }
-                    case L'\\':
-                    {
-                        in++;
-                        *(out++)=L'\\';
-                        *(out++)=L'\\';
-                        break;
-                    }
-                    default:
-                    {
-                        *(out++)=*in;
-                        break;
-                    }
-                }
-                break;
-            }
-
-            case L'*':
-            {
-                *(out++)=ANY_STRING;
-                break;
-            }
-
-            case L'?':
-            {
-                *(out++)=ANY_CHAR;
-                break;
-            }
-
-            default:
-            {
-                *(out++)=*in;
-                break;
-            }
+            result.push_back(ANY_STRING);
+        }
+        else if (cs[i] == L'?')
+        {
+            result.push_back(ANY_CHAR);
+        }
+        else if (cs[i] == L'\\' && (cs[i+1] == L'*' || cs[i+1] == L'?'))
+        {
+            result.push_back(cs[i+1]);
+            i += 1;
+        }
+        else if (cs[i] == L'\\' && cs[i+1] == L'\\')
+        {
+            // Not a wildcard, but ensure the next iteration
+            // doesn't see this escaped backslash
+            result.append(L"\\\\");
+            i += 1;
+        }
+        else
+        {
+            result.push_back(cs[i]);
         }
     }
-    *out = *in;
-    return unescaped;
+    return result;
 }
 
-
 /**
    Find the outermost quoting style of current token. Returns 0 if
    token is not quoted.

src/parse_util.h

@@ -138,10 +138,10 @@ size_t parse_util_get_offset_from_line(const wcstring &str, int line);
 size_t parse_util_get_offset(const wcstring &str, int line, long line_offset);
 
 /**
-   Make a duplicate of the specified string, unescape wildcard
-   characters but not performing any other character transformation.
+   Return the given string, unescaping wildcard characters but not performing
+   any other character transformation.
 */
-wchar_t *parse_util_unescape_wildcards(const wchar_t *in);
+wcstring parse_util_unescape_wildcards(const wcstring &in);
 
 /**
    Checks if the specified string is a help option.