From e0c466534b30fcf5907d341a826b59619a381ef7 Mon Sep 17 00:00:00 2001
From: Beman Dawes <bdawes@acm.org>
Date: Sat, 3 Nov 2007 00:49:07 +0000
Subject: [PATCH] Detect Windows FormatMessage errors, standardize message()
 return on message-not-found errors

[SVN r40710]
---
 src/error_code.cpp       | 20 +++++++++++++-------
 test/error_code_test.cpp | 13 +++++++++++++
 2 files changed, 26 insertions(+), 7 deletions(-)

diff --git a/src/error_code.cpp b/src/error_code.cpp
index 7c029dc..02a4cf8 100644
--- a/src/error_code.cpp
+++ b/src/error_code.cpp
@@ -88,7 +88,7 @@ namespace
      || (defined(__osf__) && !defined(_REENTRANT))\
      || (defined(__vms))
       const char * c_str = std::strerror( ev );
-      return std::string( c_str ? c_str : "invalid_argument" );
+      return std::string( c_str ? c_str : "Unknown error" );
   # else
       char buf[64];
       char * bp = buf;
@@ -96,7 +96,7 @@ namespace
   #  if defined(__CYGWIN__) || defined(__USE_GNU)
       // Oddball version of strerror_r
       const char * c_str = strerror_r( ev, bp, sz );
-      return std::string( c_str ? c_str : "invalid_argument" );
+      return std::string( c_str ? c_str : "Unknown error" );
   #  else
       // POSIX version of strerror_r
       int result;
@@ -107,7 +107,7 @@ namespace
   #  if defined (__sgi)
         const char * c_str = strerror( ev );
         result = 0;
-        return std::string( c_str ? c_str : "invalid_argument" );
+        return std::string( c_str ? c_str : "Unknown error" );
   #  else
         result = strerror_r( ev, bp, sz );
   #  endif
@@ -128,7 +128,7 @@ namespace
       }
       try
       {
-      std::string msg( ( result == invalid_argument ) ? "invalid_argument" : bp );
+      std::string msg( ( result == invalid_argument ) ? "Unknown error" : bp );
       if ( sz > sizeof(buf) ) std::free( bp );
         sz = 0;
       return msg;
@@ -347,7 +347,7 @@ namespace
   {
 # ifndef BOOST_NO_ANSI_APIS  
     LPVOID lpMsgBuf;
-    ::FormatMessageA( 
+    DWORD retval = ::FormatMessageA( 
         FORMAT_MESSAGE_ALLOCATE_BUFFER | 
         FORMAT_MESSAGE_FROM_SYSTEM | 
         FORMAT_MESSAGE_IGNORE_INSERTS,
@@ -358,11 +358,14 @@ namespace
         0,
         NULL 
     );
+    if (retval == 0)
+        return std::string("Unknown error");
+        
     std::string str( static_cast<LPCSTR>(lpMsgBuf) );
     ::LocalFree( lpMsgBuf ); // free the buffer
 # else  // WinCE workaround
     LPVOID lpMsgBuf;
-    ::FormatMessageW( 
+    DWORD retval = ::FormatMessageW( 
         FORMAT_MESSAGE_ALLOCATE_BUFFER | 
         FORMAT_MESSAGE_FROM_SYSTEM | 
         FORMAT_MESSAGE_IGNORE_INSERTS,
@@ -373,10 +376,13 @@ namespace
         0,
         NULL 
     );
+    if (retval == 0)
+        return std::string("Unknown error");
     
     int num_chars = (wcslen( static_cast<LPCWSTR>(lpMsgBuf) ) + 1) * 2;
     LPSTR narrow_buffer = (LPSTR)_alloca( num_chars );
-    ::WideCharToMultiByte(CP_ACP, 0, static_cast<LPCWSTR>(lpMsgBuf), -1, narrow_buffer, num_chars, NULL, NULL);
+    if (::WideCharToMultiByte(CP_ACP, 0, static_cast<LPCWSTR>(lpMsgBuf), -1, narrow_buffer, num_chars, NULL, NULL) == 0)
+        return std::string("Unknown error");
 
     std::string str( narrow_buffer );
     ::LocalFree( lpMsgBuf ); // free the buffer
diff --git a/test/error_code_test.cpp b/test/error_code_test.cpp
index 12eb1f2..a6de9a2 100644
--- a/test/error_code_test.cpp
+++ b/test/error_code_test.cpp
@@ -144,6 +144,19 @@ int test_main( int, char ** )
   BOOST_CHECK( system_category == native_ecat );
   BOOST_CHECK( posix_category == errno_ecat );
 
+  // test error_code and error_condition message(),
+  // see Boost.Filesystem operations_test for code specific message() tests
+  ec = error_code( -1, system_category );
+  BOOST_CHECK( ec.message() == "Unknown error" );
+  ec = error_code( BOOST_ACCESS_ERROR_MACRO, system_category );
+  BOOST_CHECK( ec.message() != "" );
+  BOOST_CHECK( ec.message() != "Unknown error" );
+  dec = error_condition( -1, posix_category );
+  BOOST_CHECK( dec.message() == "Unknown error" );
+  dec = error_condition( BOOST_ACCESS_ERROR_MACRO, posix_category );
+  BOOST_CHECK( dec.message() != "" );
+  BOOST_CHECK( dec.message() != "Unknown error" );
+
 #ifdef BOOST_WINDOWS_API
   std::cout << "Windows tests...\n";
   // these tests probe the Windows posix decoder