Optimize log print by using html format

Summary:
See facebook/yoga#453. Optimizes the node log print by generating some enum text via ```enum.py``` and moving printing to new functions to reduce boilerplate code.

Changes the log output to format the nodes in html to be able to copy paste it  into browsers for quick debugging.

Hides all default values.
Closes https://github.com/facebook/yoga/pull/479

Reviewed By: gkassabli

Differential Revision: D4802184

Pulled By: emilsjolander

fbshipit-source-id: 143bd63cbc31fb0755d711062cb4e6a448049ba3

enums.py

@@ -125,6 +125,16 @@ def to_java_upper(symbol):
         out += c.upper()
     return out
 
+def to_log_lower(symbol):
+    symbol = str(symbol)
+    out = ''
+    for i in range(0, len(symbol)):
+        c = symbol[i]
+        if str.istitle(c) and i is not 0 and not str.istitle(symbol[i - 1]):
+            out += '-'
+        out += c.lower()
+    return out
+
 
 root = os.path.dirname(os.path.abspath(__file__))
 
@@ -143,9 +153,28 @@ with open(root + '/yoga/YGEnums.h', 'w') as f:
             else:
                 f.write('  YG%s%s,\n' % (name, value))
         f.write('} YG_ENUM_END(YG%s);\n' % name)
+        f.write('WIN_EXPORT const char *YG%sToString(const YG%s value);\n' % (name, name))
         f.write('\n')
     f.write('YG_EXTERN_C_END\n')
 
+# write out C body for printing
+with open(root + '/yoga/YGEnums.c', 'w') as f:
+    f.write(LICENSE)
+    f.write('#include "YGEnums.h"\n\n')
+    for name, values in sorted(ENUMS.items()):
+        f.write('const char *YG%sToString(const YG%s value){\n' % (name, name))
+        f.write('  switch(value){\n')
+        for value in values:
+            if isinstance(value, tuple):
+                f.write('    case YG%s%s:\n' % (name, value[0]))
+                f.write('      return "%s";\n' % to_log_lower(value[0]))
+            else:
+                f.write('    case YG%s%s:\n' % (name, value))
+                f.write('      return "%s";\n' % to_log_lower(value))
+        f.write('  }\n')
+        f.write('  return "unknown";\n')
+        f.write('}\n\n')
+
 # write out java files
 for name, values in sorted(ENUMS.items()):
     with open(root + '/java/com/facebook/yoga/Yoga%s.java' % name, 'w') as f: