GM: allow caller to specify which result types trigger an error

gm/gm_error.h

Index: gm/gm_error.h
===================================================================
--- gm/gm_error.h	(revision 8622)
+++ gm/gm_error.h	(working copy)
@@ -58,6 +58,42 @@
     }
 
     /**
+     * Fills in "type" with the ErrorType associated with name "name".
+     * Returns true if we found one, false if it is an unknown type name.
+     */
+    static bool getErrorTypeByName(const char name[], ErrorType *type) {
+        // TODO(epoger): how can we make sure this method stays in sync with the
+        // complete list of ErrorTypes?  Unlike getErrorTypeName(), in this case
+        // we don't have the compiler warning about missing enum values to keep
+        // us in sync...
+        if (0 == strcmp(name, "NoGpuContext")) {

[borenet, 2013/04/12 00:29:45]

Suggest making these strings constant and using them in getErrorTypeName above. 
There's probably some macro magic that can be done to convert back and forth,
but that probably isn't necessary.

[epoger, 2013/04/12 02:44:43]

Hey, I came up with an elegant, robust (IMHO) approach in patchset 3.  Whaddaya
think?

[borenet, 2013/04/12 11:55:37]

I like it!

+            *type = kNoGpuContext_ErrorType;
+            return true;
+        }
+        if (0 == strcmp(name, "IntentionallySkipped")) {
+            *type = kIntentionallySkipped_ErrorType;
+            return true;
+        }
+        if (0 == strcmp(name, "RenderModeMismatch")) {
+            *type = kRenderModeMismatch_ErrorType;
+            return true;
+        }
+        if (0 == strcmp(name, "ExpectationsMismatch")) {
+            *type = kExpectationsMismatch_ErrorType;
+            return true;
+        }
+        if (0 == strcmp(name, "MissingExpectations")) {
+            *type = kMissingExpectations_ErrorType;
+            return true;
+        }
+        if (0 == strcmp(name, "WritingReferenceImage")) {
+            *type = kWritingReferenceImage_ErrorType;
+            return true;
+        }
+        return false;
+    }
+
+    /**
      * A combination of 0 or more ErrorTypes.
      */
     class ErrorCombination {
@@ -94,6 +130,27 @@
         }
 
         /**
+         * Returns a string representation of all ErrorTypes in this
+         * ErrorCombination.
+         *
+         * @param separator text with which to separate ErrorType names
+         */
+        SkString asString(const char separator[]) const {
+            SkString s;
+            int howMany = 0;
+            for (int typeInt = 0; typeInt <= kLast_ErrorType; typeInt++) {
+                ErrorType type = static_cast<ErrorType>(typeInt);
+                if (this->includes(type)) {
+                    if (0 < howMany++) {

[borenet, 2013/04/12 00:29:45]

Is this significantly faster than (s.size() == 0)?

[epoger, 2013/04/12 02:44:43]

Probably not.  Now calling s.isEmpty()... thanks for the suggestion

+                        s.append(separator);
+                    }
+                    s.append(getErrorTypeName(type));
+                }
+            }
+            return s;
+        }
+
+        /**
          * Returns a new ErrorCombination, which includes the union of all
          * ErrorTypes in two ErrorCombination objects (this and other).
          */