[PATCH v3] BaseTools/PatchCheck.py: Add LicenseCheck

["Zhang, Shenglei" <shenglei.zhang@intel.com>]

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=2691
For files to be added to the tree, this feature will check
whether it has BSD plus patent license. If not, licenses listed in
Readme are also accepted but warning will be reported.
Otherwise, it should be error.

Cc: Bob Feng <bob.c.feng@intel.com>
Cc: Liming Gao <liming.gao@intel.com>
Signed-off-by: Shenglei Zhang <shenglei.zhang@intel.com>
---

v2: Update handling methods for different licenses.

v3: Change the position of LicenseCheck(). No functional
    update.

 BaseTools/Scripts/PatchCheck.py | 49 +++++++++++++++++++++++++++++++++
 1 file changed, 49 insertions(+)

diff --git a/BaseTools/Scripts/PatchCheck.py b/BaseTools/Scripts/PatchCheck.py
index 13da6967785d..764e66ab7a89 100755
--- a/BaseTools/Scripts/PatchCheck.py
+++ b/BaseTools/Scripts/PatchCheck.py
@@ -304,12 +304,49 @@ class GitDiffCheck:
         self.line_num = 0
         self.state = START
         self.new_bin = []
+        self.LicenseCheck(self.lines, self.count)
         while self.line_num < self.count and self.format_ok:
             line_num = self.line_num
             self.run()
             assert(self.line_num > line_num)
         self.report_message_result()
 
+    def LicenseCheck(self, lines, count):
+        self.ok = True
+        self.startcheck = False
+        self.license = True
+        line_index = 0
+        for line in lines:
+            if line.startswith('--- /dev/null'):
+                nextline = lines[line_index + 1]
+                added_file = self.Readdedfileformat.search(nextline).group(1)
+                added_file_extension = os.path.splitext(added_file)[1]
+                if added_file_extension in self.file_extension_list:
+                    self.startcheck = True
+                    self.license = False
+            if self.startcheck and self.license_format_preflix in line:
+                if self.bsd2_patent in line or self.bsd3_patent in line:
+                    self.license = True
+                else:
+                    for optional_license in self.license_optional_list:
+                        if optional_license in line:
+                            self.license = True
+                            self.warning(added_file)
+            if line_index + 1 == count or lines[line_index + 1].startswith('diff --') and self.startcheck:
+                if not self.license:
+                    error_message = "Invalid License in: " + added_file
+                    self.error(error_message)
+                self.startcheck = False
+                self.license = True
+            line_index = line_index + 1
+
+    def warning(self, *err):
+        count = 0
+        for line in err:
+            error_format = 'Warning: License accepted but not BSD plus patent license in'
+            print(error_format, line)
+            count += 1
+
     def report_message_result(self):
         if Verbose.level < Verbose.NORMAL:
             return
@@ -491,6 +528,18 @@ class GitDiffCheck:
             print(prefix, line)
             count += 1
 
+    license_format_preflix = 'SPDX-License-Identifier'
+
+    bsd2_patent = 'BSD-2-Clause-Patent'
+
+    bsd3_patent = 'BSD-3-Clause-Patent'
+
+    license_optional_list = ['BSD-2-Clause', 'BSD-3-Clause', 'MIT', 'Python-2.0', 'Zlib']
+
+    Readdedfileformat = re.compile(r'\+\+\+ b\/(.*)\n')
+
+    file_extension_list = [".c", ".h", ".inf", ".dsc", ".dec", ".py", ".bat", ".sh", ".uni", ".yaml", ".fdf", ".inc"]
+
 class CheckOnePatch:
     """Checks the contents of a git email formatted patch.
 
-- 
2.18.0.windows.1