From 8269ef49fde760d58e5df238346a6575fe406491 Mon Sep 17 00:00:00 2001
From: Joe Cheng <joe@rstudio.org>
Date: Fri, 4 Nov 2011 17:07:29 -0700
Subject: [PATCH] Don't use git show -c on versions of git earlier than 1.7.2

---
 src/cpp/core/StringUtils.cpp                  | 26 ++++++++++++++
 src/cpp/core/include/core/StringUtils.hpp     |  2 ++
 .../session/modules/SessionSourceControl.cpp  | 34 +++++++++++++++++--
 3 files changed, 60 insertions(+), 2 deletions(-)

diff --git a/src/cpp/core/StringUtils.cpp b/src/cpp/core/StringUtils.cpp
index 9f8362eaf1a..8004d4e8d65 100644
--- a/src/cpp/core/StringUtils.cpp
+++ b/src/cpp/core/StringUtils.cpp
@@ -17,10 +17,13 @@
 #include <ostream>
 
 #include <algorithm>
+#include <boost/algorithm/string/classification.hpp>
 #include <boost/algorithm/string/replace.hpp>
+#include <boost/algorithm/string/split.hpp>
 #include <boost/regex.hpp>
 
 #include <core/Log.hpp>
+#include <core/SafeConvert.hpp>
 #include <core/json/Json.hpp>
 
 #ifdef _WIN32
@@ -294,6 +297,29 @@ bool isalnum(wchar_t c)
    return lookup.at(c);
 }
 
+bool parseVersion(const std::string& str, uint64_t* pVersion)
+{
+   uint64_t version = 0;
+
+   std::vector<std::string> chunks;
+   boost::algorithm::split(chunks, str, boost::algorithm::is_any_of("."));
+
+   if (chunks.empty())
+      return false;
+
+   for (size_t i = 0; i < chunks.size() && i < 4; i++)
+   {
+      uint16_t value = core::safe_convert::stringTo<uint16_t>(
+            chunks[i], std::numeric_limits<uint16_t>::max());
+      if (value == std::numeric_limits<uint16_t>::max())
+         return false;
+      version += static_cast<uint64_t>(value) << ((3-i) * 16);
+   }
+   if (pVersion)
+      *pVersion = version;
+   return true;
+}
+
 } // namespace string_utils
 } // namespace core 
 
diff --git a/src/cpp/core/include/core/StringUtils.hpp b/src/cpp/core/include/core/StringUtils.hpp
index f3980fa7565..01593eefbc7 100644
--- a/src/cpp/core/include/core/StringUtils.hpp
+++ b/src/cpp/core/include/core/StringUtils.hpp
@@ -44,6 +44,8 @@ void convertLineEndings(std::string* str, LineEnding type);
 
 std::string filterControlChars(const std::string& str);
 
+bool parseVersion(const std::string& str, uint64_t* pVersion);
+
 template<typename T>
 T hashStable(const std::string& str)
 {
diff --git a/src/cpp/session/modules/SessionSourceControl.cpp b/src/cpp/session/modules/SessionSourceControl.cpp
index 78b5d19c0d1..0247df7b9a8 100644
--- a/src/cpp/session/modules/SessionSourceControl.cpp
+++ b/src/cpp/session/modules/SessionSourceControl.cpp
@@ -77,6 +77,10 @@ const size_t WARN_SIZE = 200 * 1024;
 // git bin dir which we detect at startup. note that if the git bin
 // is already in the path then this will be empty
 std::string s_gitBinDir;
+uint64_t s_gitVersion;
+const uint64_t GIT_1_7_2 = ((uint64_t)1 << 48) |
+                           ((uint64_t)7 << 32) |
+                           ((uint64_t)2 << 16);
 
 core::system::ProcessOptions procOptions()
 {
@@ -1060,8 +1064,12 @@ class GitVCSImpl : public VCSImpl
    virtual core::Error show(const std::string& rev,
                             std::string* pOutput)
    {
-      return runCommand(git() << "show" << "--pretty=oneline" << "-c" << "-M" << rev,
-                        pOutput, NULL);
+      ShellCommand cmd = git() << "show" << "--pretty=oneline" << "-M";
+      if (s_gitVersion >= GIT_1_7_2)
+         cmd << "-c";
+      cmd << rev;
+
+      return runCommand(cmd, pOutput, NULL);
    }
 
    virtual core::Error hasRemote(bool *pHasRemote)
@@ -2498,6 +2506,28 @@ bool tryGit(const FilePath& workingDir)
    if (error)
       LOG_ERROR(error);
 
+   // Save version
+   s_gitVersion = GIT_1_7_2;
+   core::system::ProcessResult result;
+   error = core::system::runCommand(git() << "--version",
+                                    procOptions(),
+                                    &result);
+   if (error)
+      LOG_ERROR(error);
+   else
+   {
+      if (result.exitStatus == 0)
+      {
+         boost::smatch matches;
+         if (boost::regex_search(result.stdOut,
+                                 matches,
+                                 boost::regex("\\d+(\\.\\d+)+")))
+         {
+            string_utils::parseVersion(matches[0], &s_gitVersion);
+         }
+      }
+   }
+
    return true;
 }