Move VersionTuple from clang/Basic to llvm/Support

Summary:
This kind of functionality is useful to other project apart from clang.
LLDB works with version numbers a lot, but it does not have a convenient
abstraction for this. Moving this class to a lower level library allows
it to be freely used within LLDB.

Since this class is used in a lot of places in clang, and it used to be
in the clang namespace, it seemed appropriate to add it to the list of
adopted classes in LLVM.h to avoid prefixing all uses with "llvm::".

Also, I didn't find any tests specific for this class, so I wrote a
couple of quick ones for the more interesting bits of functionality.

Reviewers: zturner, erik.pilkington

Subscribers: mgorny, cfe-commits, llvm-commits

Differential Revision: https://reviews.llvm.org/D47887

llvm-svn: 334399

1 files changed, 110 insertions, 0 deletions

diff --git a/llvm/lib/Support/VersionTuple.cpp b/llvm/lib/Support/VersionTuple.cpp
new file mode 100644
index 00000000000..3f219bfbedf
--- /dev/null
+++ b/llvm/lib/Support/VersionTuple.cpp
@@ -0,0 +1,110 @@
+//===- VersionTuple.cpp - Version Number Handling ---------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the VersionTuple class, which represents a version in
+// the form major[.minor[.subminor]].
+//
+//===----------------------------------------------------------------------===//
+#include "llvm/Support/VersionTuple.h"
+#include "llvm/Support/raw_ostream.h"
+
+using namespace llvm;
+
+std::string VersionTuple::getAsString() const {
+  std::string Result;
+  {
+    llvm::raw_string_ostream Out(Result);
+    Out << *this;
+  }
+  return Result;
+}
+
+raw_ostream &llvm::operator<<(raw_ostream &Out, const VersionTuple &V) {
+  Out << V.getMajor();
+  if (Optional<unsigned> Minor = V.getMinor())
+    Out << '.' << *Minor;
+  if (Optional<unsigned> Subminor = V.getSubminor())
+    Out << '.' << *Subminor;
+  if (Optional<unsigned> Build = V.getBuild())
+    Out << '.' << *Build;
+  return Out;
+}
+
+static bool parseInt(StringRef &input, unsigned &value) {
+  assert(value == 0);
+  if (input.empty())
+    return true;
+
+  char next = input[0];
+  input = input.substr(1);
+  if (next < '0' || next > '9')
+    return true;
+  value = (unsigned)(next - '0');
+
+  while (!input.empty()) {
+    next = input[0];
+    if (next < '0' || next > '9')
+      return false;
+    input = input.substr(1);
+    value = value * 10 + (unsigned)(next - '0');
+  }
+
+  return false;
+}
+
+bool VersionTuple::tryParse(StringRef input) {
+  unsigned major = 0, minor = 0, micro = 0, build = 0;
+
+  // Parse the major version, [0-9]+
+  if (parseInt(input, major))
+    return true;
+
+  if (input.empty()) {
+    *this = VersionTuple(major);
+    return false;
+  }
+
+  // If we're not done, parse the minor version, \.[0-9]+
+  if (input[0] != '.')
+    return true;
+  input = input.substr(1);
+  if (parseInt(input, minor))
+    return true;
+
+  if (input.empty()) {
+    *this = VersionTuple(major, minor);
+    return false;
+  }
+
+  // If we're not done, parse the micro version, \.[0-9]+
+  if (input[0] != '.')
+    return true;
+  input = input.substr(1);
+  if (parseInt(input, micro))
+    return true;
+
+  if (input.empty()) {
+    *this = VersionTuple(major, minor, micro);
+    return false;
+  }
+
+  // If we're not done, parse the micro version, \.[0-9]+
+  if (input[0] != '.')
+    return true;
+  input = input.substr(1);
+  if (parseInt(input, build))
+    return true;
+
+  // If we have characters left over, it's an error.
+  if (!input.empty())
+    return true;
+
+  *this = VersionTuple(major, minor, micro, build);
+  return false;
+}