First step of porting VisitedLinkMaster to POSIX:

base/file_util.h

Index: base/file_util.h
diff --git a/base/file_util.h b/base/file_util.h
index 4154856724e4ce8404c1007470456ee66ec07b32..c546b9aac4a12852b16cf1013cee9386200a8eec 100644
--- a/base/file_util.h
+++ b/base/file_util.h
@@ -24,6 +24,7 @@
 #include <vector>
 
 #include "base/basictypes.h"
+#include "base/scoped_ptr.h"
 #include "base/file_path.h"
 
 namespace file_util {
@@ -318,6 +319,10 @@ FILE* OpenFile(const std::wstring& filename, const char* mode);
 // Closes file opened by OpenFile. Returns true on success.
 bool CloseFile(FILE* file);
 
+// Truncates an open file to end at the location of the current file pointer.
+// This is a cross-platform analog to Windows' SetEndOfFile() function.
+bool TruncateFile(FILE* file);

[John Grabowski, 2009/01/26 19:31:08]

This might be misnamed.  For example:
  FILE *fp = fopen("/tmp/foo.txt", "w");
  fseek(fp, 500, SEEK_SET);
  file_util::TruncateFile(fp);
Will cause the file to be EXTENDED, not truncated.  
Perhaps that doesn't matter because the POSIX call, ftruncate(), is also
misnamed.

+
 // Reads the given number of bytes from the file into the buffer.  Returns
 // the number of read bytes, or -1 on error.
 int ReadFile(const std::wstring& filename, char* data, int size);
@@ -336,6 +341,18 @@ bool SetCurrentDirectory(const FilePath& path);
 // Deprecated temporary compatibility function.
 bool SetCurrentDirectory(const std::wstring& current_directory);
 
+// A class to handle auto-closing of FILE*'s.
+class ScopedFILEClose {
+ public:
+  inline void operator()(FILE* x) const {
+    if (x) {
+      fclose(x);
+    }
+  }
+};
+
+typedef scoped_ptr_malloc<FILE, ScopedFILEClose> ScopedFILE;
+
 // A class for enumerating the files in a provided path. The order of the
 // results is not guaranteed.
 //