Fix -Wincompatible-pointer-types warning from gcc (issue #1)

xlsfonts.c: In function ‘get_list’:
xlsfonts.c:204:23: warning: assignment to ‘char **’ from incompatible
 pointer type ‘const char **’ [-Wincompatible-pointer-types]
  204 |                 fonts = &pattern;
      |                       ^

v2: Split the open vs. list code to allow preserving the constness
of the argument to get_list, at the cost of less code sharing between
the two paths

Closes: #1
Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>

1 files changed, 59 insertions, 46 deletions

diff --git a/xlsfonts.c b/xlsfonts.c
index b834637..0afc53f 100644
--- a/xlsfonts.c
+++ b/xlsfonts.c
@@ -58,7 +58,7 @@ static int  font_cnt                  = 0;
 static int  min_max;
 
 typedef struct {
-    char *name;
+    const char *name;
     XFontStruct *info;
 } FontList;
 
@@ -73,7 +73,7 @@ static int  IgnoreError(Display *disp, XErrorEvent *event);
 static void PrintProperty(XFontProp *prop);
 static void ComputeFontType(XFontStruct *fs);
 static void print_character_metrics(register XFontStruct *info);
-static void do_query_font(Display *dpy, char *name);
+static void do_query_font(Display *dpy, const char *name);
 
 void
 usage(const char *errmsg)
@@ -191,57 +191,70 @@ main(int argc, char **argv)
 static void
 get_list(const char *pattern)
 {
-    int available = nnames + 1, i;
-    char **fonts;
     XFontStruct *info;
 
-    /* Get list of fonts matching pattern */
-    for (;;) {
-        if (open_instead_of_list) {
-            info = XLoadQueryFont(dpy, pattern);
+    if (open_instead_of_list) {
+        info = XLoadQueryFont(dpy, pattern);
 
-            if (info) {
-                fonts = &pattern;
-                available = 1;
-                XUnloadFont(dpy, info->fid);
-            }
-            else {
-                fonts = NULL;
-            }
-            break;
+        if (info == NULL) {
+            fprintf(stderr, "%s: pattern \"%s\" unmatched\n",
+                    program_name, pattern);
+            return;
         }
 
-        if (long_list == L_MEDIUM)
-            fonts = XListFontsWithInfo(dpy, pattern, nnames, &available, &info);
-        else
-            fonts = XListFonts(dpy, pattern, nnames, &available);
-        if (fonts == NULL || available < nnames)
-            break;
-        if (long_list == L_MEDIUM)
-            XFreeFontInfo(fonts, info, available);
-        else
-            XFreeFontNames(fonts);
-        nnames = available * 2;
-    }
-
-    if (fonts == NULL) {
-        fprintf(stderr, "%s: pattern \"%s\" unmatched\n",
-                program_name, pattern);
-        return;
-    }
-
-    font_list = realloc(font_list, (font_cnt + available) * sizeof(FontList));
-    if (font_list == NULL)
-        Fatal_Error("Out of memory!");
-    for (i = 0; i < available; i++) {
-        font_list[font_cnt].name = fonts[i];
-        if (long_list == L_MEDIUM)
-            font_list[font_cnt].info = info + i;
-        else
+        font_list = realloc(font_list, (font_cnt + 1) * sizeof(FontList));
+        if (font_list == NULL)
+            Fatal_Error("Out of memory!");
+        font_list[font_cnt].name = pattern;
+        if (long_list == L_MEDIUM) {
+            font_list[font_cnt].info = info;
+            XUnloadFont(dpy, info->fid);
+        }
+        else {
             font_list[font_cnt].info = NULL;
-
+            XFreeFont(dpy, info);
+        }
         font_cnt++;
     }
+    else {
+        /* Get list of fonts matching pattern */
+        int available = nnames + 1;
+        char **fonts;
+
+        for (;;) {
+            if (long_list == L_MEDIUM)
+                fonts = XListFontsWithInfo(dpy, pattern, nnames, &available,
+                                           &info);
+            else
+                fonts = XListFonts(dpy, pattern, nnames, &available);
+            if (fonts == NULL) {
+                fprintf(stderr, "%s: pattern \"%s\" unmatched\n",
+                        program_name, pattern);
+                return;
+            }
+            if (available < nnames)
+                break;
+            if (long_list == L_MEDIUM)
+                XFreeFontInfo(fonts, info, available);
+            else
+                XFreeFontNames(fonts);
+            nnames = available * 2;
+        }
+
+        font_list = realloc(font_list,
+                            (font_cnt + available) * sizeof(FontList));
+        if (font_list == NULL)
+            Fatal_Error("Out of memory!");
+        for (int i = 0; i < available; i++) {
+            font_list[font_cnt].name = fonts[i];
+            if (long_list == L_MEDIUM)
+                font_list[font_cnt].info = info + i;
+            else
+                font_list[font_cnt].info = NULL;
+
+            font_cnt++;
+        }
+    }
 }
 
 static int
@@ -625,7 +638,7 @@ print_character_metrics(register XFontStruct *info)
 }
 
 static void
-do_query_font(Display *display, char *name)
+do_query_font(Display *display, const char *name)
 {
     register int i;
     register XFontStruct *info = XLoadQueryFont(display, name);