Make sure optional arguments come last for chip-tool. (#12064)

The code that initializes arguments assumes the optional ones are
sorted at the end.  So make sure that's actually true.

Fixes #12063

examples/chip-tool/commands/common/Command.cpp

@@ -382,8 +382,7 @@ size_t Command::AddArgument(const char * name, const char * value, bool optional
     arg.value    = const_cast<void *>(reinterpret_cast<const void *>(value));
     arg.optional = optional;
 
-    mArgs.emplace_back(arg);
-    return mArgs.size();
+    return AddArgumentToList(std::move(arg));
 }
 
 size_t Command::AddArgument(const char * name, char ** value, bool optional)
@@ -394,8 +393,7 @@ size_t Command::AddArgument(const char * name, char ** value, bool optional)
     arg.value    = reinterpret_cast<void *>(value);
     arg.optional = optional;
 
-    mArgs.emplace_back(arg);
-    return mArgs.size();
+    return AddArgumentToList(std::move(arg));
 }
 
 size_t Command::AddArgument(const char * name, chip::CharSpan * value, bool optional)
@@ -406,8 +404,7 @@ size_t Command::AddArgument(const char * name, chip::CharSpan * value, bool opti
     arg.value    = reinterpret_cast<void *>(value);
     arg.optional = optional;
 
-    mArgs.emplace_back(arg);
-    return mArgs.size();
+    return AddArgumentToList(std::move(arg));
 }
 
 size_t Command::AddArgument(const char * name, chip::ByteSpan * value, bool optional)
@@ -418,8 +415,7 @@ size_t Command::AddArgument(const char * name, chip::ByteSpan * value, bool opti
     arg.value    = reinterpret_cast<void *>(value);
     arg.optional = optional;
 
-    mArgs.emplace_back(arg);
-    return mArgs.size();
+    return AddArgumentToList(std::move(arg));
 }
 
 size_t Command::AddArgument(const char * name, AddressWithInterface * out, bool optional)
@@ -430,8 +426,7 @@ size_t Command::AddArgument(const char * name, AddressWithInterface * out, bool
     arg.value    = reinterpret_cast<void *>(out);
     arg.optional = optional;
 
-    mArgs.emplace_back(arg);
-    return mArgs.size();
+    return AddArgumentToList(std::move(arg));
 }
 
 size_t Command::AddArgument(const char * name, int64_t min, uint64_t max, void * out, ArgumentType type, bool optional)
@@ -444,8 +439,7 @@ size_t Command::AddArgument(const char * name, int64_t min, uint64_t max, void *
     arg.max      = max;
     arg.optional = optional;
 
-    mArgs.emplace_back(arg);
-    return mArgs.size();
+    return AddArgumentToList(std::move(arg));
 }
 
 size_t Command::AddArgument(const char * name, int64_t min, uint64_t max, void * out, bool optional)
@@ -458,8 +452,7 @@ size_t Command::AddArgument(const char * name, int64_t min, uint64_t max, void *
     arg.max      = max;
     arg.optional = optional;
 
-    mArgs.emplace_back(arg);
-    return mArgs.size();
+    return AddArgumentToList(std::move(arg));
 }
 
 const char * Command::GetArgumentName(size_t index) const
@@ -486,3 +479,28 @@ const char * Command::GetAttribute(void) const
 
     return nullptr;
 }
+
+size_t Command::AddArgumentToList(Argument && argument)
+{
+    if (argument.optional || mArgs.empty() || !mArgs.back().optional)
+    {
+        // Safe to just append.
+        mArgs.emplace_back(std::move(argument));
+        return mArgs.size();
+    }
+
+    // We're inserting a non-optional arg but we already have something optional
+    // in the list.  Insert before the first optional arg.
+    for (auto cur = mArgs.cbegin(), end = mArgs.cend(); cur != end; ++cur)
+    {
+        if ((*cur).optional)
+        {
+            mArgs.emplace(cur, std::move(argument));
+            return mArgs.size();
+        }
+    }
+
+    // Never reached.
+    VerifyOrDie(false);
+    return 0;
+}

examples/chip-tool/commands/common/Command.h

@@ -193,6 +193,12 @@ class Command
     size_t AddArgument(const char * name, int64_t min, uint64_t max, void * out, ArgumentType type, bool optional);
     size_t AddArgument(const char * name, int64_t min, uint64_t max, void * out, bool optional);
 
+    /**
+     * Add the Argument to our list.  This preserves the property that all
+     * optional arguments come at the end of the list.
+     */
+    size_t AddArgumentToList(Argument && argument);
+
     const char * mName = nullptr;
     std::vector<Argument> mArgs;
 };