From 568c3c697bcc2e5099f54ade68a4fe151ec1268f Mon Sep 17 00:00:00 2001
From: Joao Paulo Magalhaes <dev@jpmag.me>
Date: Fri, 3 May 2024 00:01:22 +0200
Subject: [PATCH] improve error logging functions

---
 src/c4/yml/common.hpp | 64 +++++++++++++++++++++++--------------------
 1 file changed, 35 insertions(+), 29 deletions(-)

diff --git a/src/c4/yml/common.hpp b/src/c4/yml/common.hpp
index fb81aba03..592d21a79 100644
--- a/src/c4/yml/common.hpp
+++ b/src/c4/yml/common.hpp
@@ -6,12 +6,27 @@
 #include <cstddef>
 #include <c4/substr.hpp>
 #include <c4/yml/export.hpp>
-#include <cstdio>
 
+#ifndef C4_MSVC
+#include <alloca.h>
+#else
+#include <malloc.h>
+#endif
+
+
+#ifndef RYML_LOGBUF_SIZE
+/// size for the log buffer. individual logs may be larger than this value.
+#define RYML_LOGBUF_SIZE (256)
+#endif
+
+#ifndef RYML_LOGBUF_SIZE_MAX
+/// size for the fallback larger log buffer.
+#define RYML_LOGBUF_SIZE_MAX (1024)
+#endif
 
 #ifndef RYML_ERRMSG_SIZE
 /// size for the error message buffer
-    #define RYML_ERRMSG_SIZE 1024
+#define RYML_ERRMSG_SIZE 1024
 #endif
 
 
@@ -448,7 +463,8 @@ typedef enum {
 } BlockChomp_e;
 
 
-/** Abstracts the fact that a filter result may not fit in the intended memory. */
+/** Abstracts the fact that a scalar filter result may not fit in the
+ * intended memory. */
 struct FilterResult
 {
     C4_ALWAYS_INLINE bool valid() const noexcept { return str.str != nullptr; }
@@ -456,7 +472,8 @@ struct FilterResult
     C4_ALWAYS_INLINE csubstr get() { RYML_ASSERT(valid()); return str; }
     csubstr str;
 };
-/** Abstracts the fact that a filter result may not fit in the intended memory. */
+/** Abstracts the fact that a scalar filter result may not fit in the
+ * intended memory. */
 struct FilterResultExtending
 {
     C4_ALWAYS_INLINE bool valid() const noexcept { return str.str != nullptr; }
@@ -471,7 +488,9 @@ struct FilterResultExtending
 //-----------------------------------------------------------------------------
 //-----------------------------------------------------------------------------
 
+
 namespace detail {
+// is there a better way to do this?
 template<int8_t signedval, uint8_t unsignedval>
 struct _charconstant_t
     : public std::conditional<std::is_signed<char>::value,
@@ -529,45 +548,32 @@ namespace detail {
 template<class DumpFn, class ...Args>
 C4_NO_INLINE void _parse_dump(DumpFn dumpfn, csubstr fmt, Args&& ...args)
 {
-    char writebuf[256];
+    char writebuf[RYML_LOGBUF_SIZE];
     auto results = format_dump_resume(dumpfn, writebuf, fmt, std::forward<Args>(args)...);
     // resume writing if the results failed to fit the buffer
-    if(C4_UNLIKELY(results.bufsize > sizeof(writebuf))) // bufsize will be that of the largest element serialized. Eg int(1), will require 1 byte.
+    if(C4_UNLIKELY(results.bufsize > RYML_LOGBUF_SIZE)) // bufsize will be that of the largest element serialized. Eg int(1) will require 1 byte.
     {
-        results = format_dump_resume(dumpfn, results, writebuf, fmt, std::forward<Args>(args)...);
-        if(C4_UNLIKELY(results.bufsize > sizeof(writebuf)))
-        {
-            results = format_dump_resume(dumpfn, results, writebuf, fmt, std::forward<Args>(args)...);
-            C4_CHECK(results.bufsize <= sizeof(writebuf));
-        }
+        const size_t bufsize = results.bufsize <= RYML_LOGBUF_SIZE_MAX ? results.bufsize : RYML_LOGBUF_SIZE_MAX;
+        #ifdef C4_MSVC
+        substr largerbuf = {static_cast<char*>(_alloca(bufsize)), results.bufsize};
+        #else
+        substr largerbuf = {static_cast<char*>(alloca(bufsize)), results.bufsize};
+        #endif
+        results = format_dump_resume(dumpfn, results, largerbuf, fmt, std::forward<Args>(args)...);
     }
 }
 template<class ...Args>
-C4_NO_INLINE void _report_err(Callbacks const& C4_RESTRICT callbacks, Location const& C4_RESTRICT loc, csubstr fmt, Args const& C4_RESTRICT ...args)
+C4_NORETURN C4_NO_INLINE void _report_err(Callbacks const& C4_RESTRICT callbacks, csubstr fmt, Args const& C4_RESTRICT ...args)
 {
     char errmsg[RYML_ERRMSG_SIZE] = {0};
     detail::_SubstrWriter writer(errmsg);
     auto dumpfn = [&writer](csubstr s){ writer.append(s); };
     _parse_dump(dumpfn, fmt, args...);
     writer.append('\n');
-    if(loc.name.len)
-        _parse_dump(dumpfn, "{}:", loc.name);
-    _parse_dump(dumpfn, "{}:{}: ", loc.line, loc.col);
-    size_t len = writer.pos < RYML_ERRMSG_SIZE ? writer.pos : RYML_ERRMSG_SIZE;
-    callbacks.m_error(errmsg, len, loc, callbacks.m_user_data);
-}
-template<class ...Args>
-C4_NO_INLINE void _report_err(Callbacks const& C4_RESTRICT callbacks, csubstr fmt, Args const& C4_RESTRICT ...args)
-{
-    char errmsg[RYML_ERRMSG_SIZE] = {0};
-    detail::_SubstrWriter writer(errmsg);
-    auto dumpfn = [&writer](csubstr s){ writer.append(s); };
-    _parse_dump(dumpfn, fmt, args...);
-    writer.append('\n');
-    size_t len = writer.pos < RYML_ERRMSG_SIZE ? writer.pos : RYML_ERRMSG_SIZE;
+    const size_t len = writer.pos < RYML_ERRMSG_SIZE ? writer.pos : RYML_ERRMSG_SIZE;
     callbacks.m_error(errmsg, len, {}, callbacks.m_user_data);
+    C4_UNREACHABLE_AFTER_ERR();
 }
-
 } // namespace detail