From 6ae7e24675cff4ff6b808c3024f45083f35ced97 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?John=20Ankarstr=C3=B6m?= <john@ankarstrom.se>
Date: Sat, 3 Sep 2022 15:28:56 +0200
Subject: Improve error handling.

---
 c/data.h | 20 +++++++++++++-------
 1 file changed, 13 insertions(+), 7 deletions(-)

(limited to 'c/data.h')

diff --git a/c/data.h b/c/data.h
index 2c287a2..bbc01d2 100644
--- a/c/data.h
+++ b/c/data.h
@@ -5,9 +5,12 @@
 #include <windows.h>
 #include <libxml/xmlerror.h>
 
+#include "err.h"
 #include "util.h"
 #include "win32.h"
 
+using namespace std::string_literals;
+
 struct XmlError : public std::exception
 {
 	const char* msg;
@@ -102,6 +105,7 @@ struct FileView
 	Unique<HANDLE, CloseHandle> hf;
 	Unique<HANDLE, CloseHandle> hm;
 	Unique<T*, FreeView> view;
+	const wchar_t* filename;
 	size_t c;
 
 	static FileView Initialized(const wchar_t* filename, size_t c, size_t cInit = 0)
@@ -118,7 +122,7 @@ struct FileView
 			return {filename, c};
 	}
 
-	FileView(const wchar_t* filename, size_t c) : c(c)
+	FileView(const wchar_t* filename, size_t c) : filename(filename), c(c)
 	{
 		hf = CreateFile(filename, GENERIC_READ|GENERIC_WRITE,
 		    0, nullptr, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, nullptr);
@@ -127,9 +131,9 @@ struct FileView
 				hf = CreateFile(filename, GENERIC_READ|GENERIC_WRITE,
 				    0, nullptr, CREATE_NEW, FILE_ATTRIBUTE_NORMAL, nullptr);
 				if (hf.Bad(INVALID_HANDLE_VALUE))
-					throw Win32Error();
+					throw Err(WINDOWS, L"File "s + filename + L" could not be created: %s");
 			} else
-				throw Win32Error();
+				throw Err(WINDOWS, L"File "s + filename + L" could not be opened: %s");
 		}
 
 		LARGE_INTEGER cbMap;
@@ -137,11 +141,11 @@ struct FileView
 		hm = CreateFileMapping(hf.v, nullptr, PAGE_READWRITE,
 		    cbMap.HighPart, cbMap.LowPart, nullptr);
 		if (hm.Bad(0))
-			throw Win32Error();
+			throw Err(WINDOWS, L"File mapping for "s + filename + L" could not be created: %s");
 
 		view = reinterpret_cast<T*>(MapViewOfFile(hm.v, FILE_MAP_ALL_ACCESS, 0, 0, 0));
 		if (view.Bad(0))
-			throw Win32Error();
+			throw Err(WINDOWS, L"View for "s + filename + L"could not be mapped: %s");
 	}
 
 	/* Access element by index, performing bounds check and, if
@@ -150,7 +154,8 @@ struct FileView
 	T& At(size_t i)
 	{
 		if (i >= c)
-			throw std::out_of_range("index larger than buffer");
+			throw Err(GENERIC, L"Element in "s + filename +
+			    L" could not be accessed: Index larger than buffer.");
 
 		T& t = view.v[i];
 
@@ -159,7 +164,8 @@ struct FileView
 				T t_;
 				memcpy(&t, &t_, sizeof(T));
 			} else if (t.version != Version<T>)
-				throw std::runtime_error("invalid struct version");
+				throw Err(GENERIC, L"Element in "s + filename +
+				    L" could not be accessed: Invalid format version.");
 		}
 
 		/* TODO: Use a custom exception type that informs the
-- 
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