Bug 1188468 - Allow script to force updating a generated file even if the file is actually not changed. r=gps

python/mozbuild/mozbuild/util.py

@@ -109,6 +109,25 @@ def ensureParentDir(path):
                 raise
 
 
+def readFileContent(name, mode):
+    """Read the content of file, returns tuple (file existed, file content)"""
+    existed = False
+    old_content = None
+    try:
+        existing = open(name, mode)
+        existed = True
+    except IOError:
+        pass
+    else:
+        try:
+            old_content = existing.read()
+        except IOError:
+            pass
+        finally:
+            existing.close()
+    return existed, old_content
+
+
 class FileAvoidWrite(BytesIO):
     """File-like object that buffers output and only writes if content changed.
 
@@ -127,6 +146,7 @@ class FileAvoidWrite(BytesIO):
         self._capture_diff = capture_diff
         self.diff = None
         self.mode = mode
+        self.force_update = False
 
     def write(self, buf):
         if isinstance(buf, unicode):
@@ -146,23 +166,11 @@ class FileAvoidWrite(BytesIO):
         """
         buf = self.getvalue()
         BytesIO.close(self)
-        existed = False
-        old_content = None
 
-        try:
-            existing = open(self.name, self.mode)
-            existed = True
-        except IOError:
-            pass
-        else:
-            try:
-                old_content = existing.read()
-                if old_content == buf:
-                    return True, False
-            except IOError:
-                pass
-            finally:
-                existing.close()
+        existed, old_content = readFileContent(self.name, self.mode)
+        if not self.force_update and old_content == buf:
+            assert existed
+            return existed, False
 
         ensureParentDir(self.name)
         with open(self.name, 'w') as file:

security/manager/ssl/tests/unit/pycert.py

@@ -589,6 +589,9 @@ class Certificate:
 def main(output, inputPath):
     with open(inputPath) as configStream:
         output.write(Certificate(configStream).toPEM())
+    # Force updating the output file even if the content does not change
+    # so that we won't be called again simply because of the mtime.
+    output.force_update = True
 
 # When run as a standalone program, this will read a specification from
 # stdin and output the certificate as PEM to stdout.

security/manager/ssl/tests/unit/pykey.py

@@ -700,6 +700,9 @@ def keyFromSpecification(specification):
 def main(output, inputPath):
     with open(inputPath) as configStream:
         output.write(keyFromSpecification(configStream.read().strip()).toPEM())
+    # Force updating the output file even if the content does not change
+    # so that we won't be called again simply because of the mtime.
+    output.force_update = True
 
 # When run as a standalone program, this will read a specification from
 # stdin and output the certificate as PEM to stdout.