[PATCH v5 4/7] kernel32: Implement GetUserDefaultGeoName().

[João Diogo Ferreira]

Signed-off-by: João Diogo Craveiro Ferreira <devilj at outlook.pt>
---
Supersedes: 172514
V5: Remove superfluous SetLastError(), amend documentation,
simplify code a bit.
---
 dlls/kernel32/kernel32.spec |   1 +
 dlls/kernel32/locale.c      | 115 ++++++++++++++++++++++++++++++++++++
 include/winnls.h            |   1 +
 3 files changed, 117 insertions(+)

diff --git a/dlls/kernel32/kernel32.spec b/dlls/kernel32/kernel32.spec
index 9898bdec6e..c2dd727135 100644
--- a/dlls/kernel32/kernel32.spec
+++ b/dlls/kernel32/kernel32.spec
@@ -869,6 +869,7 @@
 # @ stub GetUILanguageInfo
 @ stdcall -arch=x86_64 GetUmsCompletionListEvent(ptr ptr)
 # @ stub -arch=x86_64 GetUmsSystemThreadInformation
+@ stdcall GetUserDefaultGeoName(ptr long)
 @ stdcall -import GetUserDefaultLCID()
 @ stdcall -import GetUserDefaultLangID()
 @ stdcall -import GetUserDefaultLocaleName(ptr long)
diff --git a/dlls/kernel32/locale.c b/dlls/kernel32/locale.c
index 5731f42cdf..31c20f365b 100644
--- a/dlls/kernel32/locale.c
+++ b/dlls/kernel32/locale.c
@@ -4141,6 +4141,121 @@ GEOID WINAPI GetUserGeoID(GEOCLASS geoclass)
     return ret;
 }
 
+/******************************************************************************
+ *           GetUserDefaultGeoName (KERNEL32.@)
+ *
+ * Retrieves the name of the user's geographic location.
+ *
+ * This name is a two-letter ISO 3166 country code
+ * or a three-digit UN M.49 code for anything other than countries (e.g. continents).
+ *
+ * If buffer_len is 0, this function will return the minimum length
+ * required for a buffer to hold the name.
+ *
+ * PARAMS
+ *   buffer     [O] Pointer to a buffer to hold the name.
+ *   buffer_len [I] Length of the buffer, including null terminator, measured in WCHARs.
+ *
+ * RETURNS
+ *   SUCCESS: Number of WCHARs written to the buffer -OR- minimum buffer length required.
+ *   FAILURE: Zero. Call GetLastError() to determine the cause.
+ *
+ * NOTES
+ *   On failure, GetLastError() will return one of the following values:
+ *     - ERROR_INVALID_PARAMETER: one of the parameters was invalid.
+ *     - ERROR_INSUFFICIENT_BUFFER: the specified buffer was too small to hold the name.
+ */
+int WINAPI GetUserDefaultGeoName(WCHAR *buffer, int buffer_len)
+{
+    int ret = 0, name_len = 0;
+    WCHAR fallback[] = {'0','0','1',0}; /* World */
+    int fallback_len = ARRAY_SIZE(fallback);
+
+    static const WCHAR geokeyname[] = {'G','e','o',0};
+    HANDLE hkey, hsubkey;
+    KEY_VALUE_PARTIAL_INFORMATION kvi;
+    WCHAR valuename[] = {'N','a','m','e',0};
+    UNICODE_STRING uvaluename;
+    DWORD reg_len;
+
+    TRACE("(%p, %d)\n", buffer, buffer_len);
+
+    if (buffer_len < 0 || (buffer_len && !buffer))
+    {
+        SetLastError(ERROR_INVALID_PARAMETER);
+        return 0;
+    }
+
+    RtlInitUnicodeString(&uvaluename, valuename);
+
+    if ((hkey = create_registry_key()) &&
+        (hsubkey = NLS_RegOpenKey(hkey, geokeyname)) &&
+        NtQueryValueKey(hsubkey, &uvaluename, KeyValuePartialInformation,
+                        &kvi, sizeof(kvi), &reg_len) == STATUS_BUFFER_OVERFLOW)
+        /* If we don't get an overflow, it's the wrong value. */
+        name_len = kvi.DataLength / sizeof(WCHAR);
+
+    if (name_len)
+    {
+        if (!buffer_len)
+            ret = name_len;
+        else if (buffer_len < name_len)
+        {
+            SetLastError(ERROR_INSUFFICIENT_BUFFER);
+            ret = 0;
+        }
+        else if (buffer_len >= name_len)
+        {
+            KEY_VALUE_PARTIAL_INFORMATION *kviptr;
+            DWORD kvi_size = sizeof(*kviptr) + (name_len * sizeof(WCHAR));
+
+            if ((kviptr = HeapAlloc(GetProcessHeap(), 0, kvi_size)))
+            {
+                NTSTATUS status = NtQueryValueKey(hsubkey, &uvaluename, KeyValuePartialInformation,
+                                                  kviptr, kvi_size, &reg_len);
+                if (status == STATUS_SUCCESS)
+                {
+                    memcpy(buffer, kviptr->Data, name_len * sizeof(WCHAR));
+                    ret = name_len;
+                }
+                else
+                {
+                    ERR("Failure: status=0x%x, alloc'd kvi size = %d (needed %d), DataLength=%u\n",
+                        status, kvi_size, reg_len, kviptr->DataLength);
+                    ret = 0;
+                }
+                HeapFree(GetProcessHeap(), 0, kviptr);
+            }
+            else
+            {
+                ERR("We couldn't allocate enough memory.\n");
+                ret = 0;
+            }
+        }
+    }
+    else
+    {
+        TRACE("We've fallen back to our hardcoded value.\n");
+
+        if (!buffer_len)
+            ret = fallback_len;
+        else if (buffer_len < fallback_len)
+        {
+            SetLastError(ERROR_INSUFFICIENT_BUFFER);
+            ret = 0;
+        }
+        else if (buffer_len >= fallback_len)
+        {
+            strcpyW(buffer, fallback);
+            ret = fallback_len;
+        }
+    }
+
+    if (hsubkey) NtClose(hsubkey);
+    if (hkey) NtClose(hkey);
+    return ret;
+}
+
 /******************************************************************************
 *           set_geo_reg
 *
diff --git a/include/winnls.h b/include/winnls.h
index 4f84c64f81..6e60ceaa1d 100644
--- a/include/winnls.h
+++ b/include/winnls.h
@@ -935,6 +935,7 @@ WINBASEAPI INT         WINAPI GetTimeFormatA(LCID,DWORD,const SYSTEMTIME*,LPCSTR
 WINBASEAPI INT         WINAPI GetTimeFormatEx(LPCWSTR,DWORD,const SYSTEMTIME*,LPCWSTR,LPWSTR,INT);
 WINBASEAPI INT         WINAPI GetTimeFormatW(LCID,DWORD,const SYSTEMTIME*,LPCWSTR,LPWSTR,INT);
 #define                       GetTimeFormat WINELIB_NAME_AW(GetTimeFormat)
+WINBASEAPI int         WINAPI GetUserDefaultGeoName(WCHAR*,int);
 WINBASEAPI LANGID      WINAPI GetUserDefaultLangID(void);
 WINBASEAPI LCID        WINAPI GetUserDefaultLCID(void);
 WINBASEAPI INT         WINAPI GetUserDefaultLocaleName(LPWSTR,int);
-- 
2.23.0