[backend] be a little more principled in loading fonts

src/backend/sdl.c

@@ -1,5 +1,6 @@
 #include "../backend.h"
 #include "../ctxt/theme.h"
+#include "../util.h"
 #include "../util/region.h"
 #include "../concurrent/msgq.h"
 #include "../concurrent/msg.h"
@@ -145,25 +146,42 @@ struct ax_font_h {
     TTF_Font* font;
 };
 
-static void load_fonts(
+static int load_font(
-    struct ax_backend* bac,
+    struct rgn* rgn, const char* path, size_t size,
-    struct font_list* fl)
+    struct ax_font_h** out_fh, const char** out_err)
 {
+    struct ax_font_h* fh = ralloc_typed(rgn, struct ax_font_h, 1);
+    if ((fh->font = TTF_OpenFont(path, size)) == NULL) {
+        *out_err = TTF_GetError();
+        return 1;
+    }
+    *out_fh = fh;
+    return 0;
+}
+
+static void load_fonts(struct ax_backend* bac, struct font_list* fl)
+{
+    int rv = 0;
+    const char* err;
+
     for (; fl != NULL; fl = fl->next) {
         struct ax_theme* thm = fl->thm;
-        struct msgq* cb_mq = fl->cb_mq;
+        struct ax_font_h* fh;
-        const char* path = thm->font_path[fl->cat];
+        if ((rv = load_font(bac->rgn,
-        size_t size = thm->font_size[fl->cat];
+                            thm->font_path[fl->cat],
-
+                            thm->font_size[fl->cat],
-        struct ax_font_h* handle = ralloc_typed(bac->rgn, struct ax_font_h, 1);
+                            &fh, &err)) != 0) {
-        handle->font = TTF_OpenFont(path, size);
+            goto fail;
-        thm->font_handle[fl->cat] = handle;
+        }
-
+        bool is_loaded = ax__theme_set_font_handle(thm, fl->cat, fh);
-        if (ax__theme_is_loaded(thm)) {
+        if (is_loaded) {
             struct ax_msg_theme_loaded* m =
-                msgq_begin_send_typed(cb_mq, ax_msg_theme_loaded);
+                msgq_begin_send_typed(fl->cb_mq, ax_msg_theme_loaded);
             m->theme = thm;
-            msgq_end_send(cb_mq);
+            msgq_end_send(fl->cb_mq);
         }
     }
+
+fail:
+    ASSERT(rv == 0, "error loading font: %s", err);
 }

src/ctxt/theme.c

@@ -12,6 +12,10 @@ static const char* default_font_path(struct rgn* rgn)
     return "/usr/share/fonts/liberation/LiberationSans-Regular.ttf";
 }
 
+/* -----------------------------------------------------------------------------
+ * Theme builder functions
+ * -------------------------------------------------------------------------- */
+
 void ax__theme_builder_init(struct ax_theme_builder* thmb, struct rgn* rgn)
 {
     thmb->rgn = rgn;
@@ -83,7 +87,6 @@ void ax__theme_builder_finish(
 
     if (thmb->err != NULL) {
         thm->err = rstrdup(dst_rgn, thmb->err);
-        return;
     }
 
     const char* dflt_font_path = (thmb->dflt_font_path == NULL) ?
@@ -97,6 +100,53 @@ void ax__theme_builder_finish(
             dflt_font_path :
             rstrdup(dst_rgn, thm->font_path[i]);
     }
+
+    pthread_mutex_init(&thm->handles_mx, NULL);
+    rgn_pin(dst_rgn, thm, (void*) pthread_mutex_destroy);
+}
+
+/* -----------------------------------------------------------------------------
+ * Theme functions
+ * -------------------------------------------------------------------------- */
+
+static inline bool is_loaded(struct ax_theme* thm)
+{
+    for (size_t i = 0; i < AX_FONT__COUNT; i++) {
+        if (thm->font_handle[i] == NULL) {
+            return false;
+        }
+    }
+    return true;
+}
+
+struct ax_font_h* ax__theme_font_handle(
+    struct ax_theme* thm,
+    enum ax_font_cat i)
+{
+    pthread_mutex_lock(&thm->handles_mx);
+    struct ax_font_h* h = thm->font_handle[i];
+    pthread_mutex_unlock(&thm->handles_mx);
+    return h;
+}
+
+bool ax__theme_is_loaded(struct ax_theme* thm)
+{
+    pthread_mutex_lock(&thm->handles_mx);
+    bool l = is_loaded(thm);
+    pthread_mutex_unlock(&thm->handles_mx);
+    return l;
+}
+
+bool ax__theme_set_font_handle(
+    struct ax_theme* thm,
+    enum ax_font_cat i,
+    struct ax_font_h* h)
+{
+    pthread_mutex_lock(&thm->handles_mx);
+    thm->font_handle[i] = h;
+    bool l = is_loaded(thm);
+    pthread_mutex_unlock(&thm->handles_mx);
+    return l;
 }
 
 void ax__theme_request_load(
@@ -133,6 +183,7 @@ int ax__string_to_font_cat(const char* str, enum ax_font_cat* out_cat)
     return 0;
 }
 
+/*
 void ax__debug_theme(struct ax_theme* thm)
 {
     printf("=========\nTHEME INFO:\n");
@@ -152,3 +203,4 @@ void ax__debug_theme(struct ax_theme* thm)
                str, thm->font_path[i], thm->font_size[i]);
     }
 }
+*/

src/ctxt/theme.h

@@ -3,6 +3,7 @@
 #include <stdint.h>
 #include <stdbool.h>
 #include <stddef.h>
+#include <pthread.h>
 
 struct rgn;
 struct msgq;
@@ -42,6 +43,7 @@ struct ax_theme {
     size_t            font_size[AX_FONT__COUNT];
     const char*       font_path[AX_FONT__COUNT];
     struct ax_font_h* font_handle[AX_FONT__COUNT];
+    pthread_mutex_t   handles_mx;
 };
 
 struct ax_theme_builder {
@@ -74,22 +76,6 @@ void ax__theme_builder_finish(
     struct rgn* dst_rgn,
     struct ax_theme** out_thm);
 
-void ax__theme_request_load(
-    struct ax_theme* thm,
-    struct msgq* req_mq,
-    struct msgq* res_mq);
-
-static inline bool ax__theme_is_loaded(
-    struct ax_theme* thm)
-{
-    for (size_t i = 0; i < AX_FONT__COUNT; i++) {
-        if (thm->font_handle[i] == NULL) {
-            return false;
-        }
-    }
-    return true;
-}
-
 static inline int64_t ax__theme_color(
     struct ax_theme* thm,
     enum ax_color_cat i)
@@ -108,5 +94,23 @@ static inline const char* ax__theme_font(
     return thm->font_path[i];
 }
 
+struct ax_font_h* ax__theme_font_handle(
+    struct ax_theme* thm,
+    enum ax_font_cat i);
 
+bool ax__theme_is_loaded(
+    struct ax_theme* thm);
+
+bool ax__theme_set_font_handle( // returns `true` if the font is now loaded
+    struct ax_theme* thm,
+    enum ax_font_cat i,
+    struct ax_font_h* h);
+
+void ax__theme_request_load(
+    struct ax_theme* thm,
+    struct msgq* req_mq,
+    struct msgq* res_mq);
+
+/*
 void ax__debug_theme(struct ax_theme* thm);
+*/