src/third_party/devtools/scripts/build/devtools_file_hashes.py

#!/usr/bin/env python
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import hashlib
import os.path

try:
    import json
except ImportError:
    import simplejson as json


def save_hashes(hashes_file_path, hashes):
    try:
        with open(hashes_file_path, "wt") as hashes_file:
            json.dump(hashes, hashes_file, indent=4, separators=(",", ": "))
    except:
        print "ERROR: Failed to write %s" % hashes_file_path
        raise


def load_hashes(hashes_file_path):
    try:
        with open(hashes_file_path, "r") as hashes_file:
            hashes = json.load(hashes_file)
    except:
        return {}
    return hashes


def calculate_file_hash(file_path):
    with open(file_path) as file:
        data = file.read()
        md5_hash = hashlib.md5(data).hexdigest()
    return md5_hash


def files_with_invalid_hashes(hash_file_path, file_paths):
    hashes = load_hashes(hash_file_path)
    result = []
    for file_path in file_paths:
        file_name = os.path.basename(file_path)
        if calculate_file_hash(file_path) != hashes.get(file_name, ""):
            result.append(file_path)
    return result


def update_file_hashes(hash_file_path, file_paths):
    hashes = {}
    for file_path in file_paths:
        file_name = os.path.basename(file_path)
        hashes[file_name] = calculate_file_hash(file_path)
    save_hashes(hash_file_path, hashes)