Improve file opening on Windows

[libs/core.git] / source / io / file.cpp

diff --git a/source/io/file.cpp b/source/io/file.cpp
index 862b607c9d00e08db7ce4e10bc2843ba1bd473ba..805a9e8dba0072270d90a8cb695faa681e710e3a 100644 (file)
--- a/source/io/file.cpp
+++ b/source/io/file.cpp
@@ -17,18 +17,22 @@ File::File(const string &fn, Mode m, CreateMode cm)
 {
        if(!(m&M_RDWR))
                throw invalid_argument("File::File mode");
-       if(cm&~(C_CREATE|C_TRUNCATE))
+       if(cm&~(C_CREATE|C_TRUNCATE|C_EXCLUSIVE))
+               throw invalid_argument("File::File create");
+       if((cm&C_EXCLUSIVE) && (!(cm&C_CREATE) || (cm&C_TRUNCATE)))
                throw invalid_argument("File::File create");
 
        mode = m;
 
 #ifdef WIN32
        int flags = 0;
+       int share_flags = 0;
        int create_flags = OPEN_EXISTING;
 
        if(mode&M_READ)
                flags |= GENERIC_READ;
-       else if(mode&M_WRITE)
+
+       if(mode&M_WRITE)
        {
                flags |= GENERIC_WRITE;
 
@@ -37,16 +41,21 @@ File::File(const string &fn, Mode m, CreateMode cm)
                case C_NONE:     create_flags = OPEN_EXISTING; break;
                case C_CREATE:   create_flags = OPEN_ALWAYS; break;
                case C_TRUNCATE: create_flags = TRUNCATE_EXISTING; break;
-               case C_CREATE+C_TRUNCATE: create_flags = CREATE_ALWAYS; break;
+               case C_OVERWRITE: create_flags = CREATE_ALWAYS; break;
+               case C_NEW:      create_flags = CREATE_NEW; break;
                }
        }
+       else
+               share_flags = FILE_SHARE_READ;
 
-       *handle = CreateFile(fn.c_str(), flags, 0, 0, create_flags, FILE_ATTRIBUTE_NORMAL, 0);
+       *handle = CreateFile(fn.c_str(), flags, share_flags, 0, create_flags, FILE_ATTRIBUTE_NORMAL, 0);
        if(!handle)
        {
                int err = GetLastError();
                if(err==ERROR_FILE_NOT_FOUND)
                        throw file_not_found(fn);
+               else if(err==ERROR_FILE_EXISTS)
+                       throw file_already_exists(fn);
                else
                        throw system_error(format("CreateFile(%s)", fn), err);
        }
@@ -66,6 +75,8 @@ File::File(const string &fn, Mode m, CreateMode cm)
                        flags |= O_CREAT;
                if(cm&C_TRUNCATE)
                        flags |= O_TRUNC;
+               if(cm&C_EXCLUSIVE)
+                       flags |= O_EXCL;
        }
        if(mode&M_APPEND)
                flags |= O_APPEND;
@@ -78,6 +89,8 @@ File::File(const string &fn, Mode m, CreateMode cm)
                int err = errno;
                if(err==ENOENT)
                        throw file_not_found(fn);
+               else if(err==EEXIST)
+                       throw file_already_exists(fn);
                else
                        throw system_error(format("open(%s)", fn), err);
        }