[NTGDI][FREETYPE][SDK] Rewrite NtGdiGetCharABCWidthsW (#8704)

Refactor and improve readability.
JIRA issue: CORE-20505
- Add GreGetCharABCWidthsW helper function.
- Rewrite NtGdiGetCharABCWidthsW by using
  GreGetCharABCWidthsW.

sdk/include/psdk/ntgdi.h

@@ -1678,7 +1678,7 @@ APIENTRY
 NtGdiGetCharABCWidthsW(
     _In_ HDC hdc,
     _In_ UINT wchFirst,
-    _In_ ULONG cwch,
+    _In_ UINT cwch,
     _In_reads_opt_(cwch) PCWCH pwch,
     _In_ FLONG fl,
     _Out_writes_bytes_(cwch * sizeof(ABC)) PVOID pvBuf);

win32ss/gdi/ntgdi/font.c

@@ -1370,3 +1370,64 @@ Cleanup:
         ExFreePoolWithTag(pSafePwc, GDITAG_TEXT);
     return ret;
 }
+
+/* This function is called from GetCharABCWidthsA/W/I and GetCharABCWidthsFloatA/W. */
+BOOL NTAPI
+NtGdiGetCharABCWidthsW(
+    _In_ HDC hDC,
+    _In_ UINT FirstChar,
+    _In_ UINT Count,
+    _In_reads_opt_(Count) PCWCH UnSafepwch,
+    _In_ FLONG fl,
+    _Out_writes_bytes_(Count * sizeof(ABC)) PVOID Buffer)
+{
+    BOOL ret = FALSE;
+    PVOID SafeBuff = NULL;
+    PWCHAR Safepwch = NULL;
+    ULONG cbABCs;
+    NTSTATUS Status;
+    WCHAR Stackpwch[28];
+    ABC StackABCs[28];
+
+    if (!Buffer || (UnSafepwch && !Count) || Count > MAX_TEXT_BUFFER / sizeof(ABC))
+        return FALSE;
+
+    if (UnSafepwch)
+    {
+        UINT pwchSize = Count * sizeof(WCHAR);
+        if (Count <= _countof(Stackpwch))
+            Safepwch = Stackpwch;
+        else
+            Safepwch = ExAllocatePoolWithTag(PagedPool, pwchSize, GDITAG_TEXT);
+
+        if (!Safepwch)
+            return FALSE;
+
+        Status = MmCopyFromCaller(Safepwch, UnSafepwch, pwchSize);
+        if (!NT_SUCCESS(Status))
+            goto Cleanup;
+    }
+
+    cbABCs = Count * sizeof(ABC);
+    if (Count <= _countof(StackABCs))
+        SafeBuff = StackABCs;
+    else
+        SafeBuff = ExAllocatePoolWithTag(PagedPool, cbABCs, GDITAG_TEXT);
+
+    if (!SafeBuff)
+        goto Cleanup;
+
+    ret = GreGetCharABCWidthsW(hDC, FirstChar, Count, Safepwch, fl, SafeBuff);
+    if (ret)
+    {
+        Status = MmCopyToCaller(Buffer, SafeBuff, cbABCs);
+        ret = NT_SUCCESS(Status);
+    }
+
+Cleanup:
+    if (SafeBuff && SafeBuff != StackABCs)
+        ExFreePoolWithTag(SafeBuff, GDITAG_TEXT);
+    if (Safepwch && Safepwch != Stackpwch)
+        ExFreePoolWithTag(Safepwch, GDITAG_TEXT);
+    return ret;
+}

win32ss/gdi/ntgdi/freetype.c

@@ -7449,95 +7449,68 @@ cleanup:
     return Result;
 }
 
+static BOOL FASTCALL IntSelectFaceCharmap(FT_Face face)
+{
+    if (face->charmap)
+        return TRUE;
+
+    FT_CharMap charmap, found = NULL;
+    for (UINT i = 0; i < (UINT)face->num_charmaps; i++)
+    {
+        charmap = face->charmaps[i];
+        if (charmap->encoding != 0)
+        {
+            found = charmap;
+            break;
+        }
+    }
+
+    if (!found && FT_IS_SFNT(face)) // Not found and (TrueType or OpenType)?
+    {
+        DPRINT1("WARNING: Could not find desired charmap!\n");
+        return FALSE;
+    }
+
+    if (found)
+    {
+        IntLockFreeType();
+        FT_Set_Charmap(face, found);
+        IntUnLockFreeType();
+    }
+
+    return TRUE;
+}
 
 /*
-* @implemented
-*/
-BOOL
-APIENTRY
-NtGdiGetCharABCWidthsW(
+ * @implemented
+ */
+BOOL APIENTRY
+GreGetCharABCWidthsW(
     _In_ HDC hDC,
     _In_ UINT FirstChar,
-    _In_ ULONG Count,
-    _In_reads_opt_(Count) PCWCH UnSafepwch,
+    _In_ UINT Count,
+    _In_reads_opt_(Count) PCWCH Safepwch,
     _In_ FLONG fl,
-    _Out_writes_bytes_(Count * sizeof(ABC)) PVOID Buffer)
+    _Out_writes_bytes_(Count * sizeof(ABC)) PVOID SafeBuffer)
 {
-    LPABC SafeBuff;
-    LPABCFLOAT SafeBuffF = NULL;
+    PABC SafeBuffI;
+    PABCFLOAT SafeBuffF;
     PDC dc;
     PDC_ATTR pdcattr;
     PTEXTOBJ TextObj;
     PFONTGDI FontGDI;
     FT_Face face;
-    FT_CharMap charmap, found = NULL;
-    UINT i, glyph_index, BufferSize;
-    HFONT hFont = 0;
-    NTSTATUS Status = STATUS_SUCCESS;
-    PWCHAR Safepwch = NULL;
-    LOGFONTW *plf;
-
-    if (!Buffer)
-    {
-        EngSetLastError(ERROR_INVALID_PARAMETER);
-        return FALSE;
-    }
-
-    if (UnSafepwch)
-    {
-        UINT pwchSize = Count * sizeof(WCHAR);
-        Safepwch = ExAllocatePoolWithTag(PagedPool, pwchSize, GDITAG_TEXT);
-
-        if(!Safepwch)
-        {
-            EngSetLastError(ERROR_NOT_ENOUGH_MEMORY);
-            return FALSE;
-        }
-
-        _SEH2_TRY
-        {
-            ProbeForRead(UnSafepwch, pwchSize, 1);
-            RtlCopyMemory(Safepwch, UnSafepwch, pwchSize);
-        }
-        _SEH2_EXCEPT(EXCEPTION_EXECUTE_HANDLER)
-        {
-            Status = _SEH2_GetExceptionCode();
-        }
-        _SEH2_END;
-    }
-
-    if (!NT_SUCCESS(Status))
-    {
-        if(Safepwch)
-            ExFreePoolWithTag(Safepwch , GDITAG_TEXT);
-
-        SetLastNtError(Status);
-        return FALSE;
-    }
-
-    BufferSize = Count * sizeof(ABC); // Same size!
-    SafeBuff = ExAllocatePoolWithTag(PagedPool, BufferSize, GDITAG_TEXT);
-    if (!fl) SafeBuffF = (LPABCFLOAT) SafeBuff;
-    if (SafeBuff == NULL)
-    {
-        if(Safepwch)
-            ExFreePoolWithTag(Safepwch , GDITAG_TEXT);
-
-        EngSetLastError(ERROR_NOT_ENOUGH_MEMORY);
-        return FALSE;
-    }
+    UINT i, glyph_index;
+    HFONT hFont = NULL;
+    PLOGFONTW plf;
 
     dc = DC_LockDc(hDC);
     if (dc == NULL)
     {
-        ExFreePoolWithTag(SafeBuff, GDITAG_TEXT);
-
-        if(Safepwch)
-            ExFreePoolWithTag(Safepwch , GDITAG_TEXT);
-
         EngSetLastError(ERROR_INVALID_HANDLE);
         return FALSE;
     }
+
     pdcattr = dc->pdcattr;
     hFont = pdcattr->hlfntNew;
     TextObj = RealizeFontInit(hFont);
@@ -7546,11 +7519,6 @@ NtGdiGetCharABCWidthsW(
 
     if (TextObj == NULL)
     {
-        ExFreePoolWithTag(SafeBuff, GDITAG_TEXT);
-
-        if(Safepwch)
-            ExFreePoolWithTag(Safepwch , GDITAG_TEXT);
-
         EngSetLastError(ERROR_INVALID_HANDLE);
         return FALSE;
     }
@@ -7558,33 +7526,11 @@ NtGdiGetCharABCWidthsW(
     FontGDI = ObjToGDI(TextObj->Font, FONT);
 
     face = FontGDI->SharedFace->Face;
-    if (face->charmap == NULL)
+    if (!IntSelectFaceCharmap(face))
     {
-        for (i = 0; i < (UINT)face->num_charmaps; i++)
-        {
-            charmap = face->charmaps[i];
-            if (charmap->encoding != 0)
-            {
-                found = charmap;
-                break;
-            }
-        }
-
-        if (!found)
-        {
-            DPRINT1("WARNING: Could not find desired charmap!\n");
-            ExFreePoolWithTag(SafeBuff, GDITAG_TEXT);
-
-            if(Safepwch)
-                ExFreePoolWithTag(Safepwch , GDITAG_TEXT);
-
-            EngSetLastError(ERROR_INVALID_HANDLE);
-            return FALSE;
-        }
-
-        IntLockFreeType();
-        FT_Set_Charmap(face, found);
-        IntUnLockFreeType();
+        TEXTOBJ_UnlockText(TextObj);
+        EngSetLastError(ERROR_INVALID_HANDLE);
+        return FALSE;
     }
 
     plf = &TextObj->logfont.elfEnumLogfontEx.elfLogFont;
@@ -7594,18 +7540,20 @@ NtGdiGetCharABCWidthsW(
     IntRequestFontSize(dc, FontGDI, plf->lfWidth, plf->lfHeight);
     FT_Set_Transform(face, NULL, NULL);
 
+    if (!fl)
+        SafeBuffF = SafeBuffer;
+    else
+        SafeBuffI = SafeBuffer;
+
     for (i = FirstChar; i < FirstChar+Count; i++)
     {
         int adv, lsb, bbx, left, right;
 
         if (Safepwch)
-        {
             glyph_index = get_glyph_index_flagged(face, Safepwch[i - FirstChar], (fl & GCABCW_INDICES));
-        }
         else
-        {
             glyph_index = get_glyph_index_flagged(face, i, (fl & GCABCW_INDICES));
-        }
+
         FT_Load_Glyph(face, glyph_index, FT_LOAD_DEFAULT);
 
         left = (INT)face->glyph->metrics.horiBearingX  & -64;
@@ -7628,27 +7576,15 @@ NtGdiGetCharABCWidthsW(
         }
         else
         {
-            SafeBuff[i - FirstChar].abcA = lsb;
-            SafeBuff[i - FirstChar].abcB = bbx;
-            SafeBuff[i - FirstChar].abcC = adv - lsb - bbx;
+            SafeBuffI[i - FirstChar].abcA = lsb;
+            SafeBuffI[i - FirstChar].abcB = bbx;
+            SafeBuffI[i - FirstChar].abcC = adv - lsb - bbx;
         }
     }
+
     IntUnLockFreeType();
     TEXTOBJ_UnlockText(TextObj);
-    Status = MmCopyToCaller(Buffer, SafeBuff, BufferSize);
 
-    ExFreePoolWithTag(SafeBuff, GDITAG_TEXT);
-
-    if(Safepwch)
-        ExFreePoolWithTag(Safepwch , GDITAG_TEXT);
-
-    if (!NT_SUCCESS(Status))
-    {
-        SetLastNtError(Status);
-        return FALSE;
-    }
-
-    DPRINT("NtGdiGetCharABCWidths Worked!\n");
     return TRUE;
 }
 
@@ -7669,7 +7605,6 @@ GreGetCharWidthW(
     PTEXTOBJ TextObj;
     PFONTGDI FontGDI;
     FT_Face face;
-    FT_CharMap charmap, found = NULL;
     UINT i, glyph_index;
     HFONT hFont = 0;
     LOGFONTW *plf;
@@ -7697,33 +7632,11 @@ GreGetCharWidthW(
     FontGDI = ObjToGDI(TextObj->Font, FONT);
 
     face = FontGDI->SharedFace->Face;
-    if (face->charmap == NULL)
+    if (!IntSelectFaceCharmap(face))
     {
-        // FIXME: Select better charmap
-        for (i = 0; i < (UINT)face->num_charmaps; i++)
-        {
-            charmap = face->charmaps[i];
-            if (charmap->encoding != 0)
-            {
-                found = charmap;
-                break;
-            }
-        }
-
-        if (!found && FT_IS_SFNT(face)) // Not found and (TrueType or OpenType)?
-        {
-            DPRINT1("WARNING: Could not find desired charmap!\n");
-            EngSetLastError(ERROR_INVALID_HANDLE);
-            TEXTOBJ_UnlockText(TextObj);
-            return FALSE;
-        }
-
-        if (found)
-        {
-            IntLockFreeType();
-            FT_Set_Charmap(face, found);
-            IntUnLockFreeType();
-        }
+        TEXTOBJ_UnlockText(TextObj);
+        EngSetLastError(ERROR_INVALID_HANDLE);
+        return FALSE;
     }
 
     plf = &TextObj->logfont.elfEnumLogfontEx.elfLogFont;

win32ss/gdi/ntgdi/text.h

@@ -173,5 +173,14 @@ GreGetCharWidthW(
     _In_ UINT FirstChar,
     _In_ UINT Count,
     _In_reads_opt_(Count) PCWCH Safepwc,
-    _In_ ULONG fl,
+    _In_ FLONG fl,
     _Out_writes_bytes_(Count * sizeof(INT)) PVOID pTmpBuffer);
+
+BOOL APIENTRY
+GreGetCharABCWidthsW(
+    _In_ HDC hDC,
+    _In_ UINT FirstChar,
+    _In_ UINT Count,
+    _In_reads_opt_(Count) PCWCH Safepwch,
+    _In_ FLONG fl,
+    _Out_writes_bytes_(Count * sizeof(ABC)) PVOID SafeBuffer);