Eliminate PS printing edge cases

There were a couple possible edge cases with the new postscript language
level identification that could lead to incorrect behavior.
(1) Printer is stuck in GDI centric mode. In this case the change to
POSTSCRIPT_PASSTHROUGH will cause a failure. Check for POSTSCRIPT_
PASSTHROUGH support before running it.
(2) Printer gets set to PS mode but the postscript level detection
returns something weird. This would result in driver trying to send
Gdi commands to a printer in PS mode.
These issues are resolved in this patch.

Finally, this fixes the problem of postscript printers not printing
if the postscript feature is disabled by using GDI mode instead of
PS mode to query the postscript level.

BUG=614988

Review-Url: https://codereview.chromium.org/2714073002
Cr-Commit-Position: refs/heads/master@{#453312}

chrome/browser/printing/pdf_to_emf_converter.cc

@@ -373,8 +373,7 @@ bool PostScriptMetaFile::SafePlayback(HDC hdc) const {
           reinterpret_cast<const EMRGDICOMMENT*>(emf_record);
       const char* data = reinterpret_cast<const char*>(comment->Data);
       const uint16_t* ptr = reinterpret_cast<const uint16_t*>(data);
-      int ret =
-          ExtEscape(hdc, POSTSCRIPT_PASSTHROUGH, 2 + *ptr, data, 0, nullptr);
+      int ret = ExtEscape(hdc, PASSTHROUGH, 2 + *ptr, data, 0, nullptr);
       DCHECK_EQ(*ptr, ret);
     }
   }

printing/print_settings_initializer_win.cc

@@ -12,7 +12,7 @@ namespace printing {
 
 namespace {
 
-bool HasEscapeSupprt(HDC hdc, DWORD escape) {
+bool HasEscapeSupport(HDC hdc, DWORD escape) {
   const char* ptr = reinterpret_cast<const char*>(&escape);
   return ExtEscape(hdc, QUERYESCSUPPORT, sizeof(escape), ptr, 0, nullptr) > 0;
 }
@@ -21,18 +21,7 @@ bool IsTechnology(HDC hdc, const char* technology) {
   if (::GetDeviceCaps(hdc, TECHNOLOGY) != DT_RASPRINTER)
     return false;
 
-  // If postscript, try to query Postscript Identify and then set to
-  // postscript mode before calling any more ExtEscape functions. Otherwise,
-  // PSLEVEL query will not work.
-  if (strcmp(technology, "PostScript") == 0 &&
-      HasEscapeSupprt(hdc, POSTSCRIPT_IDENTIFY)) {
-    DWORD mode = PSIDENT_PSCENTRIC;
-    const char* ptr = reinterpret_cast<const char*>(&mode);
-    ExtEscape(hdc, POSTSCRIPT_IDENTIFY, sizeof(DWORD), ptr, 0, nullptr);
-    return true;
-  }
-
-  if (!HasEscapeSupprt(hdc, GETTECHNOLOGY))
+  if (!HasEscapeSupport(hdc, GETTECHNOLOGY))
     return false;
 
   char buf[256];
@@ -42,36 +31,59 @@ bool IsTechnology(HDC hdc, const char* technology) {
   return strcmp(buf, technology) == 0;
 }
 
+void SetPrinterToGdiMode(HDC hdc) {
+  // Try to set to GDI centric mode
+  DWORD mode = PSIDENT_GDICENTRIC;
+  const char* ptr = reinterpret_cast<const char*>(&mode);
+  ExtEscape(hdc, POSTSCRIPT_IDENTIFY, sizeof(DWORD), ptr, 0, nullptr);
+}
+
+int GetPrinterPostScriptLevel(HDC hdc) {
+  constexpr int param = FEATURESETTING_PSLEVEL;
+  const char* param_char_ptr = reinterpret_cast<const char*>(&param);
+  int param_out = 0;
+  char* param_out_char_ptr = reinterpret_cast<char*>(&param_out);
+  if (ExtEscape(hdc, GET_PS_FEATURESETTING, sizeof(param), param_char_ptr,
+                sizeof(param_out), param_out_char_ptr) > 0) {
+    return param_out;
+  }
+  return 0;
+}
+
 bool IsPrinterPostScript(HDC hdc, int* level) {
   static constexpr char kPostScriptDriver[] = "PostScript";
-  if (!IsTechnology(hdc, kPostScriptDriver)) {
-    return false;
-  }
 
-  // Query the PS Level if possible.
-  if (HasEscapeSupprt(hdc, GET_PS_FEATURESETTING)) {
-    constexpr int param = FEATURESETTING_PSLEVEL;
-    const char* param_char_ptr = reinterpret_cast<const char*>(&param);
-    int param_out = -1;
-    char* param_out_char_ptr = reinterpret_cast<char*>(&param_out);
-    if (ExtEscape(hdc, GET_PS_FEATURESETTING, sizeof(param), param_char_ptr,
-                  sizeof(param_out), param_out_char_ptr) > 0) {
-      if (param_out < 2 || param_out > 3)
-        return false;
-
-      *level = param_out;
-      return true;
+  // If printer does not support POSTSCRIPT_IDENTIFY, it cannot be set to GDI
+  // mode to check the language level supported. See if it looks like a
+  // postscript printer and supports the postscript functions that are
+  // supported in compatability mode. If so set to level 2 postscript.
+  if (!HasEscapeSupport(hdc, POSTSCRIPT_IDENTIFY)) {
+    if (!IsTechnology(hdc, kPostScriptDriver))
+      return false;
+    if (!HasEscapeSupport(hdc, POSTSCRIPT_PASSTHROUGH) ||
+        !HasEscapeSupport(hdc, POSTSCRIPT_DATA)) {
+      return false;
     }
-  }
-
-  // If it looks like a PS printer.
-  if (HasEscapeSupprt(hdc, POSTSCRIPT_PASSTHROUGH) &&
-      HasEscapeSupprt(hdc, POSTSCRIPT_DATA)) {
     *level = 2;
     return true;
   }
 
-  return false;
+  // Printer supports POSTSCRIPT_IDENTIFY so we can assume it has a postscript
+  // driver. Set the printer to GDI mode in order to query the postscript
+  // level. Use GDI mode instead of PostScript mode so that if level detection
+  // fails or returns language level < 2 we can fall back to normal printing.
+  // Note: This escape must be called before other escapes.
+  SetPrinterToGdiMode(hdc);
+  if (!HasEscapeSupport(hdc, GET_PS_FEATURESETTING)) {
+    // Can't query the level, use level 2 to be safe
+    *level = 2;
+    return true;
+  }
+
+  // Get the language level. If invalid or < 2, return false to set printer to
+  // normal printing mode.
+  *level = GetPrinterPostScriptLevel(hdc);
+  return *level == 2 || *level == 3;
 }
 
 bool IsPrinterXPS(HDC hdc) {