font-manager: add option API

src/reason-font-manager/FontManager.cpp

@@ -1,46 +1,55 @@
-#include <stdio.h>
-#include <caml/alloc.h>
-#include <caml/bigarray.h>
-#include <caml/callback.h>
-#include <caml/memory.h>
-#include <caml/mlvalues.h>
-#include <caml/threads.h>
-
-#include "FontDescriptor.h"
-
-extern "C" {
-    extern FontDescriptor *findFont(FontDescriptor *query);
-    extern ResultSet *findFonts(FontDescriptor *query);
-
-    CAMLprim value fm_findFont(value family, value weight, value width, value italic, value monospace) {
-        CAMLparam5(family, weight, width, italic, monospace);
-        CAMLlocal1(ret);
-
-        const char* fontFamily = String_val(family);
-        FontWeight weightToCheck = (FontWeight)Int_val(weight);
-        FontWidth widthToCheck = (FontWidth)Int_val(width);
-        int isItalic = Bool_val(italic);
-        int isMono = Bool_val(monospace);
-
-        caml_release_runtime_system();
-        FontDescriptor *query = new FontDescriptor(NULL, NULL, fontFamily, NULL, weightToCheck, widthToCheck, isItalic, isMono);
-    
-        FontDescriptor *font = findFont(query);
-        delete query;
-
-        caml_acquire_runtime_system();
-
-        ret = caml_alloc(7, 0);
-        Store_field(ret, 0, caml_copy_string(font->path));
-        Store_field(ret, 1, caml_copy_string(font->postscriptName));
-        Store_field(ret, 2, caml_copy_string(font->family));
-        Store_field(ret, 3, Val_int(font->weight));
-        Store_field(ret, 4, Val_int(font->width));
-        Store_field(ret, 5, Val_bool(font->italic));
-        Store_field(ret, 6, Val_bool(font->monospace));
-
-        delete font;
-
-        CAMLreturn(ret);
-    }
-}
+#include <caml/alloc.h>
+#include <caml/bigarray.h>
+#include <caml/callback.h>
+#include <caml/fail.h>
+#include <caml/memory.h>
+#include <caml/mlvalues.h>
+#include <caml/threads.h>
+#include <stdio.h>
+
+#include "FontDescriptor.h"
+
+extern "C" {
+
+extern FontDescriptor *findFont(FontDescriptor *query);
+extern ResultSet *findFonts(FontDescriptor *query);
+
+CAMLprim value fm_findFont(value family, value weight, value width, value italic, value monospace) {
+  CAMLparam5(family, weight, width, italic, monospace);
+  CAMLlocal1(ret);
+
+  const char *fontFamily = String_val(family);
+  FontWeight weightToCheck = (FontWeight)Int_val(weight);
+  FontWidth widthToCheck = (FontWidth)Int_val(width);
+  int isItalic = Bool_val(italic);
+  int isMono = Bool_val(monospace);
+
+  caml_release_runtime_system();
+
+  FontDescriptor *query = new FontDescriptor(NULL, NULL, fontFamily, NULL, weightToCheck, widthToCheck, isItalic, isMono);
+  FontDescriptor *font = findFont(query);
+
+  delete query;
+
+  if (font == NULL) {
+    caml_raise_not_found();
+    return Val_unit;
+  }
+
+  caml_acquire_runtime_system();
+
+  ret = caml_alloc(7, 0);
+
+  Store_field(ret, 0, caml_copy_string(font->path));
+  Store_field(ret, 1, caml_copy_string(font->postscriptName));
+  Store_field(ret, 2, caml_copy_string(font->family));
+  Store_field(ret, 3, Val_int(font->weight));
+  Store_field(ret, 4, Val_int(font->width));
+  Store_field(ret, 5, Val_bool(font->italic));
+  Store_field(ret, 6, Val_bool(font->monospace));
+
+  delete font;
+
+  CAMLreturn(ret);
+}
+}

src/reason-font-manager/FontManager.re

@@ -2,9 +2,33 @@ module FontDescriptor = FontDescriptor;
 module FontWeight = FontWeight;
 module FontWidth = FontWidth;
 
-external _findFont: (string, int, int, bool, bool) => FontDescriptor.raw =
+external findFont': (string, int, int, bool, bool) => FontDescriptor.raw =
   "fm_findFont";
 
+let findFontOpt =
+    (
+      ~weight=FontWeight.Normal,
+      ~width=FontWidth.Undefined,
+      ~family: string,
+      ~italic: bool,
+      ~mono: bool,
+      (),
+    ) => {
+  switch (
+    findFont'(
+      family,
+      FontWeight.toInt(weight),
+      FontWidth.toInt(width),
+      italic,
+      mono,
+    )
+  ) {
+  | exception Not_found => None
+  | raw => Some(FontDescriptor.ofRaw(raw))
+  };
+};
+
+exception Font_not_found;
 let findFont =
     (
       ~weight=FontWeight.Normal,
@@ -14,12 +38,8 @@ let findFont =
       ~mono: bool,
       (),
     ) => {
-  _findFont(
-    family,
-    FontWeight.toInt(weight),
-    FontWidth.toInt(width),
-    italic,
-    mono,
-  )
-  |> FontDescriptor.ofRaw;
+  switch (findFontOpt(~weight, ~width, ~family, ~italic, ~mono, ())) {
+  | None => raise(Font_not_found)
+  | Some(fontDescriptor) => fontDescriptor
+  };
 };

src/reason-font-manager/FontManager.rei

@@ -0,0 +1,25 @@
+module FontDescriptor = FontDescriptor;
+module FontWeight = FontWeight;
+module FontWidth = FontWidth;
+
+exception Font_not_found;
+let findFont:
+  (
+    ~weight: FontWeight.t=?,
+    ~width: FontWidth.t=?,
+    ~family: string,
+    ~italic: bool,
+    ~mono: bool,
+    unit
+  ) =>
+  FontDescriptor.t;
+let findFontOpt:
+  (
+    ~weight: FontWeight.t=?,
+    ~width: FontWidth.t=?,
+    ~family: string,
+    ~italic: bool,
+    ~mono: bool,
+    unit
+  ) =>
+  option(FontDescriptor.t);