Treat default command line argument properly.

tools/flags/SkCommandLineFlags.h

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SK_COMMAND_LINE_FLAGS_H
 #define SK_COMMAND_LINE_FLAGS_H
 
@@ skipping 48 matching lines @@
  *
  *  double FLAGS_real;
  *
  *  These flags can be set by specifying, for example, "--integer 7" and
  *  "--real 3.14" on the command line.
  *
  *  Unlike the others, the line
  *
  *  DEFINE_string(args, .., ..);
  *
  *  creates an array:

[epoger, 2013/04/23 16:54:13]

Thoughts for a separate CL: I think it would be cleaner for DEFINE_string to
specify a *single* string value, like how DEFINE_int32 specifies a single int32
value.  Any spaces within the string value would be preserved.

Then you could create a separate DEFINE_string_array() that acts like what we
have now.

[scroggo, 2013/04/24 18:42:36]

Good idea. I have filed https://code.google.com/p/skia/issues/detail?id=1262

  *
  *  SkCommandLineFlags::StringArray FLAGS_args;
  *
  *  If the default value is the empty string, FLAGS_args will default to a size
  *  of zero. Otherwise it will default to a size of 1 with the default string
  *  as its value. All strings that follow the flag on the command line (until
  *  a string that begins with '-') will be entries in the array.
  *
  *  Any flag can be referenced from another file after using the following:
  *
@@ skipping 45 matching lines @@
 
         bool isEmpty() const { return this->count() == 0; }
 
     private:
         void reset() { fStrings.reset(); }
 
         void append(const char* string) {
             fStrings.push_back().set(string);
         }
 
+        void append(const char* string, size_t length) {
+            fStrings.push_back().set(string, length);
+        }
+
         SkTArray<SkString> fStrings;
 
         friend class SkFlagInfo;
     };
 
 private:
     static SkFlagInfo* gHead;
     static SkString    gUsage;
 
     // For access to gHead.
@@ skipping 73 matching lines @@
 
     // Create flags of the desired type, and append to the list.
     static bool CreateBoolFlag(const char* name, const char* shortName, bool* pBool,
                                bool defaultValue, const char* helpString) {
         SkFlagInfo* info = SkNEW_ARGS(SkFlagInfo, (name, shortName, kBool_FlagType, helpString));
         info->fBoolValue = pBool;
         *info->fBoolValue = info->fDefaultBool = defaultValue;
         return true;
     }
 
     static bool CreateStringFlag(const char* name, const char* shortName,

[epoger, 2013/04/23 16:54:13]

Please add documentation for this (and maybe other?) functions.  Specifically,
it took me some digging to understand that pStrings is passed in just so we have
a place to store strings (whatever strings were stored there before this call
will be nuked by a reset() within this call)

[scroggo, 2013/04/24 18:42:36]

Done.

                                  SkCommandLineFlags::StringArray* pStrings,
-                                 const char* defaultValue, const char* helpString) {
-        SkFlagInfo* info = SkNEW_ARGS(SkFlagInfo, (name, shortName, kString_FlagType, helpString));
-        info->fDefaultString.set(defaultValue);
-
-        info->fStrings = pStrings;
-        info->fStrings->reset();
-        // If default is "", leave the array empty.
-        if (info->fDefaultString.size() > 0) {
-            info->fStrings->append(defaultValue);
-        }
-        return true;
-    }
+                                 const char* defaultValue, const char* helpString);
 
     static bool CreateIntFlag(const char* name, int32_t* pInt,
                               int32_t defaultValue, const char* helpString) {
         SkFlagInfo* info = SkNEW_ARGS(SkFlagInfo, (name, NULL, kInt_FlagType, helpString));
         info->fIntValue = pInt;
         *info->fIntValue = info->fDefaultInt = defaultValue;
         return true;
     }
 
     static bool CreateDoubleFlag(const char* name, double* pDouble,
@@ skipping 135 matching lines @@
     double*              fDoubleValue;
     double               fDefaultDouble;
     SkCommandLineFlags::StringArray* fStrings;
     // Both for the help string and in case fStrings is empty.
     SkString             fDefaultString;
 
     // In order to keep a linked list.
     SkFlagInfo*          fNext;
 };
 #endif // SK_COMMAND_LINE_FLAGS_H