add support for reasoning_format and parse_tool_calls

Author: aldehir

common/chat.cpp

@@ -1364,15 +1364,27 @@ static void common_chat_parse_gpt_oss(common_chat_msg_parser & builder) {
     );
     static const common_regex builtin_tool_call_regex("(?:browser|python)[\\s\\S]*<\\|message\\|>");
 
-    auto consume_until_next = [&]() {
-        if (auto res = builder.try_find_regex(start_regex, std::string::npos, false)) {
+    // Save the start of the message so we can roll back when we encounter a tool call and parse_tool_calls == false.
+    size_t message_start_pos = 0;
+
+    // Similarly, save the channel start so we can roll back to defer reasoning parsing to builder.
+    size_t channel_start_pos = 0;
+
+    auto consume_until_next = [&](size_t from = std::string::npos) {
+        if (auto res = builder.try_find_regex(start_regex, from, false)) {
             auto begin = res->groups[0].begin;
             builder.move_to(begin);
             return res->prelude;
         }
         return builder.consume_rest();
     };
 
+    auto consume_whole_message = [&]() {
+        // Move back to the start and consume up to the next message
+        builder.move_to(message_start_pos);
+        return consume_until_next(message_start_pos + 1);
+    };
+
     auto tool_call = [&]() {
         if (auto res = builder.try_consume_regex(user_tool_call_regex)) {
             auto name = builder.str(res->groups[1]);
@@ -1391,7 +1403,7 @@ static void common_chat_parse_gpt_oss(common_chat_msg_parser & builder) {
             if (builder.syntax().parse_tool_calls) {
                 tool_call();
             } else {
-                consume_until_next();
+                builder.add_content(consume_whole_message());
             }
         } else if (builder.try_consume_regex(message_regex)) {
             if (!builder.try_find_regex(end_regex)) {
@@ -1414,18 +1426,22 @@ static void common_chat_parse_gpt_oss(common_chat_msg_parser & builder) {
         if (builder.try_consume_regex(to_regex)) {
             tool_call(); // built-in tools can be called in the analysis channel
         } else if (builder.try_consume_regex(message_regex)) {
-            if (auto res = builder.try_find_regex(end_regex, std::string::npos, false)) {
-                builder.add_reasoning_content(res->prelude);
+            // Defer reasoning parsing to builder
+            builder.move_to(channel_start_pos);
+
+            if (builder.syntax().reasoning_format != COMMON_REASONING_FORMAT_NONE) {
+                builder.try_parse_reasoning("<|channel|>analysis<|message|>", "<|end|>");
             } else {
-                builder.add_reasoning_content(builder.consume_rest());
+                builder.add_content(consume_until_next());
             }
         } else {
             throw common_chat_msg_parse_exception("expected: <|message|>, got: " + consume_until_next());
         }
     };
 
     auto channel = [&]() {
-        if (builder.try_consume_regex(channel_regex)) {
+        if (auto channel = builder.try_consume_regex(channel_regex)) {
+            channel_start_pos = channel->groups[0].begin;
             if (auto res = builder.try_consume_regex(channel_type_regexp)) {
                 auto type = builder.str(res->groups[0]);
                 if (type == "analysis") {
@@ -1456,7 +1472,8 @@ static void common_chat_parse_gpt_oss(common_chat_msg_parser & builder) {
     }
 
     // Read in complete messages until done or partial exception raised
-    while (builder.try_find_literal("<|start|>")) {
+    while (auto res = builder.try_find_literal("<|start|>")) {
+        message_start_pos = res->groups[0].begin;
         try {
             start();
         } catch (const common_chat_msg_parse_exception & e) {