From 50d9a2609ae283910d78c05d028ef378dc3d6617 Mon Sep 17 00:00:00 2001
From: Kevin Mitchell <kevmitch@gmail.com>
Date: Wed, 17 Feb 2016 02:40:43 -0800
Subject: windows_utils: try and use FormatMessage for errors.

This is useful in particular for GetLastError, unfortunately, it's stil pretty
dumb with regards to WASAPI or D3D specific errors, so keep the
hresult_to_string switch.
---
 osdep/windows_utils.c | 24 ++++++++++++++++++++++--
 osdep/windows_utils.h |  2 +-
 2 files changed, 23 insertions(+), 3 deletions(-)

(limited to 'osdep')

diff --git a/osdep/windows_utils.c b/osdep/windows_utils.c
index 21ff40a89d..a1ea32191a 100644
--- a/osdep/windows_utils.c
+++ b/osdep/windows_utils.c
@@ -124,9 +124,29 @@ static char *hresult_to_str(const HRESULT hr)
 #undef E
 }
 
+static char *fmtmsg_buf(char *buf, size_t buf_size, DWORD errorID)
+{
+    DWORD n = FormatMessageA(FORMAT_MESSAGE_FROM_SYSTEM |
+                             FORMAT_MESSAGE_IGNORE_INSERTS,
+                             NULL, errorID, 0, buf, buf_size, NULL);
+    if (!n && GetLastError() == ERROR_MORE_DATA) {
+        snprintf(buf, buf_size,
+                 "<Insufficient buffer size (%zd) for error message>",
+                 buf_size);
+    } else {
+        if (n > 0 && buf[n-1] == '\n')
+            buf[n-1] = '\0';
+        if (n > 1 && buf[n-2] == '\r')
+            buf[n-2] = '\0';
+    }
+    return buf;
+}
+#define fmtmsg(hr) fmtmsg_buf((char[243]){0}, 243, (hr))
+
 char *mp_HRESULT_to_str_buf(char *buf, size_t buf_size, HRESULT hr)
 {
-    snprintf(buf, buf_size, "%s (0x%"PRIx32")",
-             hresult_to_str(hr), (uint32_t) hr);
+    char* msg = fmtmsg(hr);
+    msg = msg[0] ? msg : hresult_to_str(hr);
+    snprintf(buf, buf_size, "%s (0x%"PRIx32")", msg, (uint32_t)hr);
     return buf;
 }
diff --git a/osdep/windows_utils.h b/osdep/windows_utils.h
index 851eb1b4e3..6c750ded2a 100644
--- a/osdep/windows_utils.h
+++ b/osdep/windows_utils.h
@@ -23,7 +23,7 @@
 char *mp_GUID_to_str_buf(char *buf, size_t buf_size, const GUID *guid);
 #define mp_GUID_to_str(guid) mp_GUID_to_str_buf((char[40]){0}, 40, (guid))
 char *mp_HRESULT_to_str_buf(char *buf, size_t buf_size, HRESULT hr);
-#define mp_HRESULT_to_str(hr) mp_HRESULT_to_str_buf((char[60]){0}, 60, (hr))
+#define mp_HRESULT_to_str(hr) mp_HRESULT_to_str_buf((char[256]){0}, 256, (hr))
 #define mp_LastError_to_str() mp_HRESULT_to_str(HRESULT_FROM_WIN32(GetLastError()))
 
 #endif
-- 
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