Pango plugin gv_get_ps_fontlist: postpone 'family_name' allocation

Rather than allocating this upfront and then potentially needing to free it
later, we can use a string view to postpone the allocation to when we know it is
actually needed. This works because the lifetime of the backing memory extends
until the call to `g_free(families)`. This also fixes the lack of allocation
failure checks; instead of `strdup` we now call `strview_str` that gracefully
exits on allocation failure.

diff --git a/plugin/pango/gvgetfontlist_pango.c b/plugin/pango/gvgetfontlist_pango.c
index 251db4cd947dff013605ca7e46aea4c5e93f5469..b51c29e8804625605eeade3be57f4858d68523c5 100644 (file)
--- a/plugin/pango/gvgetfontlist_pango.c
+++ b/plugin/pango/gvgetfontlist_pango.c
@@ -16,6 +16,7 @@
 #include <ctype.h>
 #include <cgraph/alloc.h>
 #include <cgraph/strcasecmp.h>
+#include <cgraph/strview.h>
 
 /* FIXME - the following declaration should be removed
  * when configure is coordinated with flags passed to the
@@ -332,7 +333,6 @@ static availfont_t *gv_get_ps_fontlist(PangoFontMap * fontmap)
     int i, k, array_sz, availfaces = 0;
     availfont_t *gv_af_p, *gv_afs;
     const char *name;
-    char *family_name;
 
     /* Get a list of font families installed on the system */
     pango_font_map_list_families(fontmap, &families, &n_families);
@@ -346,7 +346,7 @@ static availfont_t *gv_get_ps_fontlist(PangoFontMap * fontmap)
        gv_afs = gv_af_p+j;
        gv_ps_fontdef = gv_ps_fontdefs+j;
        gv_afs->gv_ps_fontname = gv_ps_fontdef->fontname;
-       family_name = NULL;
+       strview_t family_name = {0};
        /* Search the installed system font families for the current
           Graphvis PS font family name, i.e. AvantGarde */
        for (i = 0; i < n_families; i++) {
@@ -354,38 +354,38 @@ static availfont_t *gv_get_ps_fontlist(PangoFontMap * fontmap)
            name = pango_font_family_get_name(family);
            /* if a match is found get the installed font faces */
            if (strcasecmp(gv_ps_fontdef->fontname, name) == 0) {
-               family_name = strdup(name);
+               family_name = strview(name, '\0');
                availfaces = get_faces(family);
            }
-           if (family_name)
+           if (family_name.data != NULL)
                break;
        }
        /* if a match is not found on the primary Graphviz font family,
           search for a match on the equivalent font family names */
-       if (!family_name) {
+       if (family_name.data == NULL) {
            array_sz = gv_ps_fontdef->eq_sz;
            for (k = 0; k < array_sz; k++) {
                for (i = 0; i < n_families; i++) {
                    family = families[i];
                    name = pango_font_family_get_name(family);
                    if (strcasecmp(gv_ps_fontdef->equiv[k], name) == 0) {
-                       family_name = strdup(name);
+                       family_name = strview(name, '\0');
                        availfaces = get_faces(family);
                        break;
                    }
                }
-               if (family_name)
+               if (family_name.data != NULL)
                    break;
            }
        }
        /* if a match is not found on the equivalent font family names, search
           for a match on the generic family name assigned to the Graphviz PS font */
-       if (!family_name) {
+       if (family_name.data == NULL) {
            for (i = 0; i < n_families; i++) {
                family = families[i];
                name = pango_font_family_get_name(family);
                if (strcasecmp(gv_ps_fontdef->generic_name, name) == 0) {
-                   family_name = strdup(name);
+                   family_name = strview(name, '\0');
                    availfaces = get_faces(family);
                    break;
                }
@@ -393,13 +393,12 @@ static availfont_t *gv_get_ps_fontlist(PangoFontMap * fontmap)
        }
        /* if not match is found on the generic name, set the available font
           name to NULL */
-       if (family_name && availfaces) {
-           gv_afs->fontname = family_name;
+       if (family_name.data != NULL && availfaces) {
+           gv_afs->fontname = strview_str(family_name);
            gv_afs->faces = availfaces;
        } else {
            gv_afs->fontname = NULL;
            gv_afs->faces = 0;
-           free(family_name);
        }
     }
     g_free(families);