[clang-format] Modified SortIncludes and IncludeCategories to priority for sorting #includes within the Group Category.

Summary:
This new Style rule is made as a part of adding support for NetBSD KNF in clang-format. NetBSD have it's own priority of includes which should be followed while formatting NetBSD code. This style sorts the Cpp Includes according to the priorities of NetBSD, as mentioned in the [Style Guide](http://cvsweb.netbsd.org/bsdweb.cgi/src/share/misc/style?rev=HEAD&content-type=text/x-cvsweb-markup)
 The working of this Style rule shown below:

**Configuration:**
This revision introduces a new field under IncludeCategories named `SortPriority` which defines the priority of ordering the `#includes` and the `Priority` will define the categories for grouping the `#include blocks`.

Reviewers: cfe-commits, mgorny, christos, MyDeveloperDay

Reviewed By: MyDeveloperDay

Subscribers: lebedev.ri, rdwampler, christos, mgorny, krytarowski

Patch By: Manikishan

Tags: #clang, #clang-format

Differential Revision: https://reviews.llvm.org/D64695

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@372919 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 25 insertions, 4 deletions

diff --git a/lib/Format/Format.cpp b/lib/Format/Format.cpp
index ba76ba083a..b64d482524 100644
--- a/lib/Format/Format.cpp
+++ b/lib/Format/Format.cpp
@@ -1771,6 +1771,7 @@ struct IncludeDirective {
   StringRef Text;
   unsigned Offset;
   int Category;
+  int Priority;
 };
 
 struct JavaImportDirective {
@@ -1834,6 +1835,7 @@ static void sortCppIncludes(const FormatStyle &Style,
                             ArrayRef<tooling::Range> Ranges, StringRef FileName,
                             StringRef Code, tooling::Replacements &Replaces,
                             unsigned *Cursor) {
+  tooling::IncludeCategoryManager Categories(Style.IncludeStyle, FileName);
   unsigned IncludesBeginOffset = Includes.front().Offset;
   unsigned IncludesEndOffset =
       Includes.back().Offset + Includes.back().Text.size();
@@ -1841,11 +1843,12 @@ static void sortCppIncludes(const FormatStyle &Style,
   if (!affectsRange(Ranges, IncludesBeginOffset, IncludesEndOffset))
     return;
   SmallVector<unsigned, 16> Indices;
-  for (unsigned i = 0, e = Includes.size(); i != e; ++i)
+  for (unsigned i = 0, e = Includes.size(); i != e; ++i) {
     Indices.push_back(i);
+  }
   llvm::stable_sort(Indices, [&](unsigned LHSI, unsigned RHSI) {
-    return std::tie(Includes[LHSI].Category, Includes[LHSI].Filename) <
-           std::tie(Includes[RHSI].Category, Includes[RHSI].Filename);
+    return std::tie(Includes[LHSI].Priority, Includes[LHSI].Filename) <
+           std::tie(Includes[RHSI].Priority, Includes[RHSI].Filename);
   });
   // The index of the include on which the cursor will be put after
   // sorting/deduplicating.
@@ -1960,9 +1963,12 @@ tooling::Replacements sortCppIncludes(const FormatStyle &Style, StringRef Code,
         int Category = Categories.getIncludePriority(
             IncludeName,
             /*CheckMainHeader=*/!MainIncludeFound && FirstIncludeBlock);
+        int Priority = Categories.getSortIncludePriority(
+            IncludeName, !MainIncludeFound && FirstIncludeBlock);
         if (Category == 0)
           MainIncludeFound = true;
-        IncludesInBlock.push_back({IncludeName, Line, Prev, Category});
+        IncludesInBlock.push_back(
+            {IncludeName, Line, Prev, Category, Priority});
       } else if (!IncludesInBlock.empty() && !EmptyLineSkipped) {
         sortCppIncludes(Style, IncludesInBlock, Ranges, FileName, Code,
                         Replaces, Cursor);
diff --git a/lib/Tooling/Inclusions/HeaderIncludes.cpp b/lib/Tooling/Inclusions/HeaderIncludes.cpp
index a7f79c33bc..e746bbb7f8 100644
--- a/lib/Tooling/Inclusions/HeaderIncludes.cpp
+++ b/lib/Tooling/Inclusions/HeaderIncludes.cpp
@@ -199,6 +199,20 @@ int IncludeCategoryManager::getIncludePriority(StringRef IncludeName,
   return Ret;
 }
 
+int IncludeCategoryManager::getSortIncludePriority(StringRef IncludeName,
+                                                   bool CheckMainHeader) const {
+  int Ret = INT_MAX;
+  for (unsigned i = 0, e = CategoryRegexs.size(); i != e; ++i)
+    if (CategoryRegexs[i].match(IncludeName)) {
+      Ret = Style.IncludeCategories[i].SortPriority;
+      if (Ret == 0)
+        Ret = Style.IncludeCategories[i].Priority;
+      break;
+    }
+  if (CheckMainHeader && IsMainFile && Ret > 0 && isMainHeader(IncludeName))
+    Ret = 0;
+  return Ret;
+}
 bool IncludeCategoryManager::isMainHeader(StringRef IncludeName) const {
   if (!IncludeName.startswith("\""))
     return false;
diff --git a/lib/Tooling/Inclusions/IncludeStyle.cpp b/lib/Tooling/Inclusions/IncludeStyle.cpp
index c53c82c836..26dc0b87cf 100644
--- a/lib/Tooling/Inclusions/IncludeStyle.cpp
+++ b/lib/Tooling/Inclusions/IncludeStyle.cpp
@@ -17,6 +17,7 @@ void MappingTraits<IncludeStyle::IncludeCategory>::mapping(
     IO &IO, IncludeStyle::IncludeCategory &Category) {
   IO.mapOptional("Regex", Category.Regex);
   IO.mapOptional("Priority", Category.Priority);
+  IO.mapOptional("SortPriority", Category.SortPriority);
 }
 
 void ScalarEnumerationTraits<IncludeStyle::IncludeBlocksStyle>::enumeration(