From 293b7b0f11052f3b0f5ff78e01299831dfb690cd Mon Sep 17 00:00:00 2001
From: apio <blobs.trading@gmail.com>
Date: Wed, 21 Dec 2022 17:38:19 +0100
Subject: [PATCH] TextConsole: Propagate UTF-8 decoding errors

---
 kernel/src/Log.cpp               | 17 ++++++++++++---
 kernel/src/video/TextConsole.cpp | 36 +++++++++++++++++---------------
 kernel/src/video/TextConsole.h   |  8 +++----
 3 files changed, 37 insertions(+), 24 deletions(-)

diff --git a/kernel/src/Log.cpp b/kernel/src/Log.cpp
index 7342419c..d13d9e0e 100644
--- a/kernel/src/Log.cpp
+++ b/kernel/src/Log.cpp
@@ -55,10 +55,21 @@ static void log_text_console(LogLevel level, const char* format, va_list origin)
         TextConsole::set_foreground(WHITE);
 
     // FIXME: Same as above.
-    pure_cstyle_format(
-        format, [](char c, void*) { TextConsole::putchar(c); }, nullptr, ap);
+    auto rc = cstyle_format(
+        format, [](char c, void*) -> Result<void> { return TextConsole::putchar(c); }, nullptr, ap);
 
-    TextConsole::putchar('\n');
+    if (rc.has_error())
+    {
+        // FIXME: Find a way to do this in a simpler way (TextConsole::wprint maybe?)
+        const wchar_t* s = L"Invalid UTF-8 in log message";
+        while (*s)
+        {
+            TextConsole::putwchar(*s);
+            s++;
+        }
+    }
+
+    TextConsole::putwchar(L'\n');
 
     TextConsole::set_background(original_background);
 
diff --git a/kernel/src/video/TextConsole.cpp b/kernel/src/video/TextConsole.cpp
index 7d124a06..abd1c139 100644
--- a/kernel/src/video/TextConsole.cpp
+++ b/kernel/src/video/TextConsole.cpp
@@ -4,6 +4,7 @@
 #include <luna/CString.h>
 #include <luna/Format.h>
 #include <luna/Result.h>
+#include <luna/ScopeGuard.h>
 #include <luna/Utf8.h>
 #include <stdarg.h>
 
@@ -120,18 +121,17 @@ namespace TextConsole
         }
     }
 
-    // FIXME: Should this function propagate errors?
-    void putchar(char c)
+    Result<void> putchar(char c)
     {
-        auto rc = utf8_decoder.feed(c);
-        if (rc.has_error())
-        {
-            utf8_decoder.reset();
-            return;
-        }
+        auto guard = make_scope_guard([] { utf8_decoder.reset(); });
+
+        auto maybe_wchar = TRY(utf8_decoder.feed(c));
+
+        guard.deactivate();
 
-        auto maybe_wchar = rc.value();
         if (maybe_wchar.has_value()) putwchar(maybe_wchar.value());
+
+        return {};
     }
 
     void set_foreground(u32 color)
@@ -166,23 +166,25 @@ namespace TextConsole
         Framebuffer::rect(0, 0, Framebuffer::width(), Framebuffer::height(), BLACK);
     }
 
-    void print(const char* str)
+    Result<void> print(const char* str)
     {
-        while (*str) putchar(*str++);
+        while (*str) TRY(putchar(*str++));
+        return {};
     }
 
-    void println(const char* str)
+    Result<void> println(const char* str)
     {
-        print(str);
-        putchar('\n');
+        TRY(print(str));
+        putwchar(L'\n');
+        return {};
     }
 
-    usize printf(const char* format, ...)
+    Result<usize> printf(const char* format, ...)
     {
         va_list ap;
         va_start(ap, format);
-        auto rc = pure_cstyle_format(
-            format, [](char c, void*) { putchar(c); }, nullptr, ap);
+        auto rc = TRY(cstyle_format(
+            format, [](char c, void*) -> Result<void> { return putchar(c); }, nullptr, ap));
         va_end(ap);
         return rc;
     }
diff --git a/kernel/src/video/TextConsole.h b/kernel/src/video/TextConsole.h
index 2c884262..464f34d9 100644
--- a/kernel/src/video/TextConsole.h
+++ b/kernel/src/video/TextConsole.h
@@ -6,14 +6,14 @@
 namespace TextConsole
 {
     void clear();
-    void putchar(char c);
+    Result<void> putchar(char c);
     void putwchar(wchar_t c);
     void set_foreground(u32 color);
     void set_background(u32 color);
     u32 foreground();
     u32 background();
     void move_to(u32 x, u32 y);
-    void print(const char* str);
-    void println(const char* str);
-    usize printf(const char* format, ...) _format(1, 2);
+    Result<void> print(const char* str);
+    Result<void> println(const char* str);
+    Result<usize> printf(const char* format, ...) _format(1, 2);
 }
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