check-package: check whitespace and empty lines

Create 3 new check functions to warn when:
- there are consecutive empty lines in the file, see [1];
- the last line of the file is empty, see [2];
- there are lines with trailing whitespace, see [3].

Apply these functions to Config.*, *.mk and *.hash, but not for *.patch
files since they can contain any of these and still be valid.

[1] http://patchwork.ozlabs.org/patch/682660/
[2] http://patchwork.ozlabs.org/patch/643288/
[3] http://patchwork.ozlabs.org/patch/398984/

Signed-off-by: Ricardo Martincoski <ricardo.martincoski@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

support/scripts/checkpackagelib.py

@@ -3,6 +3,32 @@
 from checkpackagebase import _CheckFunction
 
 
+class ConsecutiveEmptyLines(_CheckFunction):
+    def before(self):
+        self.lastline = "non empty"
+
+    def check_line(self, lineno, text):
+        if text.strip() == "" == self.lastline.strip():
+            return ["{}:{}: consecutive empty lines"
+                    .format(self.filename, lineno)]
+        self.lastline = text
+
+
+class EmptyLastLine(_CheckFunction):
+    def before(self):
+        self.lastlineno = 0
+        self.lastline = "non empty"
+
+    def check_line(self, lineno, text):
+        self.lastlineno = lineno
+        self.lastline = text
+
+    def after(self):
+        if self.lastline.strip() == "":
+            return ["{}:{}: empty line at end of file"
+                    .format(self.filename, self.lastlineno)]
+
+
 class NewlineAtEof(_CheckFunction):
     def before(self):
         self.lastlineno = 0
@@ -17,3 +43,12 @@ class NewlineAtEof(_CheckFunction):
             return ["{}:{}: missing newline at end of file"
                     .format(self.filename, self.lastlineno),
                     self.lastline]
+
+
+class TrailingSpace(_CheckFunction):
+    def check_line(self, lineno, text):
+        line = text.rstrip("\r\n")
+        if line != line.rstrip():
+            return ["{}:{}: line contains trailing whitespace"
+                    .format(self.filename, lineno),
+                    text]

support/scripts/checkpackagelib_config.py

@@ -4,4 +4,7 @@
 # checked by running "make menuconfig".
 
 # Notice: ignore 'imported but unused' from pyflakes for check functions.
+from checkpackagelib import ConsecutiveEmptyLines
+from checkpackagelib import EmptyLastLine
 from checkpackagelib import NewlineAtEof
+from checkpackagelib import TrailingSpace

support/scripts/checkpackagelib_hash.py

@@ -4,4 +4,7 @@
 # "make package-dirclean package-source".
 
 # Notice: ignore 'imported but unused' from pyflakes for check functions.
+from checkpackagelib import ConsecutiveEmptyLines
+from checkpackagelib import EmptyLastLine
 from checkpackagelib import NewlineAtEof
+from checkpackagelib import TrailingSpace

support/scripts/checkpackagelib_mk.py

@@ -5,4 +5,7 @@
 # packages enabled.
 
 # Notice: ignore 'imported but unused' from pyflakes for check functions.
+from checkpackagelib import ConsecutiveEmptyLines
+from checkpackagelib import EmptyLastLine
 from checkpackagelib import NewlineAtEof
+from checkpackagelib import TrailingSpace