More path validation for better error message

BUG: 73759524
Test: Unit test updated
Change-Id: I2774450174ad6490a1d5e6c81766a2982c2aa6f1
diff --git a/libs/hwui/PathParser.cpp b/libs/hwui/PathParser.cpp
index a48fdfc..47fcca9 100644
--- a/libs/hwui/PathParser.cpp
+++ b/libs/hwui/PathParser.cpp
@@ -156,10 +156,63 @@
     return;
 }
 
-bool PathParser::isVerbValid(char verb) {
-    verb = tolower(verb);
-    return verb == 'a' || verb == 'c' || verb == 'h' || verb == 'l' || verb == 'm' || verb == 'q' ||
-           verb == 's' || verb == 't' || verb == 'v' || verb == 'z';
+void PathParser::validateVerbAndPoints(char verb, size_t points, PathParser::ParseResult* result) {
+    size_t numberOfPointsExpected = -1;
+    switch (verb) {
+        case 'z':
+        case 'Z':
+            numberOfPointsExpected = 0;
+            break;
+        case 'm':
+        case 'l':
+        case 't':
+        case 'M':
+        case 'L':
+        case 'T':
+            numberOfPointsExpected = 2;
+            break;
+        case 'h':
+        case 'v':
+        case 'H':
+        case 'V':
+            numberOfPointsExpected = 1;
+            break;
+        case 'c':
+        case 'C':
+            numberOfPointsExpected = 6;
+            break;
+        case 's':
+        case 'q':
+        case 'S':
+        case 'Q':
+            numberOfPointsExpected = 4;
+            break;
+        case 'a':
+        case 'A':
+            numberOfPointsExpected = 7;
+            break;
+        default:
+            result->failureOccurred = true;
+            result->failureMessage += verb;
+            result->failureMessage += " is not a valid verb. ";
+            return;
+    }
+    if (numberOfPointsExpected == 0 && points == 0) {
+        return;
+    }
+    if (numberOfPointsExpected > 0 && points % numberOfPointsExpected == 0) {
+        return;
+    }
+
+    result->failureOccurred = true;
+    result->failureMessage += verb;
+    result->failureMessage += " needs to be followed by ";
+    if (numberOfPointsExpected > 0) {
+        result->failureMessage += "a multiple of ";
+    }
+    result->failureMessage += std::to_string(numberOfPointsExpected)
+            + " floats. However, " + std::to_string(points)
+            + " float(s) are found. ";
 }
 
 void PathParser::getPathDataFromAsciiString(PathData* data, ParseResult* result,
@@ -186,13 +239,11 @@
         end = nextStart(pathStr, strLen, end);
         std::vector<float> points;
         getFloats(&points, result, pathStr, start, end);
-        if (!isVerbValid(pathStr[start])) {
-            result->failureOccurred = true;
-            result->failureMessage = "Invalid pathData. Failure occurred at position " +
-                                     std::to_string(start) + " of path: " + pathStr;
-        }
-        // If either verb or points is not valid, return immediately.
+        validateVerbAndPoints(pathStr[start], points.size(), result);
         if (result->failureOccurred) {
+            // If either verb or points is not valid, return immediately.
+            result->failureMessage += "Failure occurred at position " +
+                                     std::to_string(start) + " of path: " + pathStr;
             return;
         }
         data->verbs.push_back(pathStr[start]);
@@ -203,9 +254,10 @@
     }
 
     if ((end - start) == 1 && start < strLen) {
-        if (!isVerbValid(pathStr[start])) {
-            result->failureOccurred = true;
-            result->failureMessage = "Invalid pathData. Failure occurred at position " +
+        validateVerbAndPoints(pathStr[start], 0, result);
+        if (result->failureOccurred) {
+            // If either verb or points is not valid, return immediately.
+            result->failureMessage += "Failure occurred at position " +
                                      std::to_string(start) + " of path: " + pathStr;
             return;
         }