Load validator list from file:

* Adds local file:// URL support to the [validator_list_sites] stanza.
  The file:// URL must not contain a hostname. Allows a rippled node
  operator to "sideload" a new list if their node is unable to reach
  a validator list's web site before an old list expires. Lists
  loaded from a file will be validated in the same way a downloaded
  list is validated.
* Generalize file/dir "guards" from Config test so they can be reused
  in other tests.
* Check for error when reading validators.txt. Saves some parsing and
  checking of an empty string, and will give a more meaningful error.
* Completes RIPD-1674.

src/ripple/basics/ByteUtilities.h

@@ -31,8 +31,11 @@ namespace ripple {
     template<class T>
     constexpr auto megabytes(T value) noexcept
     {
-        return kilobytes(1) * kilobytes(1) * value;
+        return kilobytes(kilobytes(value));
     }
+
+    static_assert(kilobytes(2) == 2048, "kilobytes(2) == 2048");
+    static_assert(megabytes(3) == 3145728, "megabytes(3) == 3145728");
 }
 
 #endif

src/ripple/basics/FileUtilities.h

@@ -0,0 +1,39 @@
+//------------------------------------------------------------------------------
+/*
+    This file is part of rippled: https://github.com/ripple/rippled
+    Copyright (c) 2018 Ripple Labs Inc.
+
+    Permission to use, copy, modify, and/or distribute this software for any
+    purpose  with  or without fee is hereby granted, provided that the above
+    copyright notice and this permission notice appear in all copies.
+
+    THE  SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+    WITH  REGARD  TO  THIS  SOFTWARE  INCLUDING  ALL  IMPLIED  WARRANTIES  OF
+    MERCHANTABILITY  AND  FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+    ANY  SPECIAL ,  DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+    WHATSOEVER  RESULTING  FROM  LOSS  OF USE, DATA OR PROFITS, WHETHER IN AN
+    ACTION  OF  CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+//==============================================================================
+
+#ifndef RIPPLE_BASICS_FILEUTILITIES_H_INCLUDED
+#define RIPPLE_BASICS_FILEUTILITIES_H_INCLUDED
+
+#include <boost/system/error_code.hpp>
+#include <boost/filesystem.hpp>
+#include <boost/optional.hpp>
+
+namespace ripple
+{
+
+// TODO: Should this one function have its own file, or can it
+// be absorbed somewhere else?
+
+std::string getFileContents(boost::system::error_code& ec,
+    boost::filesystem::path const& sourcePath,
+    boost::optional<std::size_t> maxSize = boost::none);
+
+}
+
+#endif

src/ripple/basics/impl/FileUtilities.cpp

@@ -0,0 +1,63 @@
+//------------------------------------------------------------------------------
+/*
+    This file is part of rippled: https://github.com/ripple/rippled
+    Copyright (c) 2018 Ripple Labs Inc.
+
+    Permission to use, copy, modify, and/or distribute this software for any
+    purpose  with  or without fee is hereby granted, provided that the above
+    copyright notice and this permission notice appear in all copies.
+
+    THE  SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+    WITH  REGARD  TO  THIS  SOFTWARE  INCLUDING  ALL  IMPLIED  WARRANTIES  OF
+    MERCHANTABILITY  AND  FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+    ANY  SPECIAL ,  DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+    WHATSOEVER  RESULTING  FROM  LOSS  OF USE, DATA OR PROFITS, WHETHER IN AN
+    ACTION  OF  CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+//==============================================================================
+
+#include <ripple/basics/FileUtilities.h>
+
+namespace ripple
+{
+
+std::string getFileContents(boost::system::error_code& ec,
+    boost::filesystem::path const& sourcePath,
+    boost::optional<std::size_t> maxSize)
+{
+    using namespace boost::filesystem;
+    using namespace boost::system::errc;
+
+    path fullPath{ canonical(sourcePath, ec) };
+    if (ec)
+        return {};
+
+    if (maxSize && (file_size(fullPath, ec) > *maxSize || ec))
+    {
+        if (!ec)
+            ec = make_error_code(file_too_large);
+        return {};
+    }
+
+    ifstream fileStream(fullPath, std::ios::in);
+
+    if (!fileStream)
+    {
+        ec = make_error_code(static_cast<errc_t>(errno));
+        return {};
+    }
+
+    const std::string result{ std::istreambuf_iterator<char>{fileStream},
+        std::istreambuf_iterator<char>{} };
+
+    if (fileStream.bad ())
+    {
+        ec = make_error_code(static_cast<errc_t>(errno));
+        return {};
+    }
+
+    return result;
+}
+
+}

src/ripple/basics/impl/StringUtilities.cpp

@@ -89,11 +89,15 @@ uint64_t uintFromHex (std::string const& strSrc)
     return uValue;
 }
 
-// TODO Callers should be using beast::URL and beast::parse_URL instead.
 bool parseUrl (parsedURL& pUrl, std::string const& strUrl)
 {
     // scheme://username:password@hostname:port/rest
-    static boost::regex reUrl ("(?i)\\`\\s*([[:alpha:]][-+.[:alpha:][:digit:]]*)://([^/]+)(/.*)?\\s*?\\'");
+    static boost::regex reUrl (
+        "(?i)\\`\\s*"
+        "([[:alpha:]][-+.[:alpha:][:digit:]]*):"    //scheme
+        "//([^/]+)?"                                 // hostname
+        "(/.*)?"                                    // path and parameters
+        "\\s*?\\'");
     boost::smatch smMatch;
 
     bool bMatch = boost::regex_match (strUrl, smMatch, reUrl); // Match status code.