1 files changed, 111 insertions, 0 deletions
diff --git a/src/rocksdb/build_tools/amalgamate.py b/src/rocksdb/build_tools/amalgamate.py
new file mode 100755
index 000000000..c5cbb3f0f
--- /dev/null
+++ b/src/rocksdb/build_tools/amalgamate.py
@@ -0,0 +1,111 @@
+#!/usr/bin/python
+# Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+
+# amalgamate.py creates an amalgamation from a unity build.
+# It can be run with either Python 2 or 3.
+# An amalgamation consists of a header that includes the contents of all public
+# headers and a source file that includes the contents of all source files and
+# private headers.
+#
+# This script works by starting with the unity build file and recursively expanding
+# #include directives. If the #include is found in a public include directory,
+# that header is expanded into the amalgamation header.
+#
+# A particular header is only expanded once, so this script will
+# break if there are multiple inclusions of the same header that are expected to
+# expand differently. Similarly, this type of code causes issues:
+#
+# #ifdef FOO
+#   #include "bar.h"
+#   // code here
+# #else
+#   #include "bar.h"            // oops, doesn't get expanded
+#   // different code here
+# #endif
+#
+# The solution is to move the include out of the #ifdef.
+
+from __future__ import print_function
+
+import argparse
+from os import path
+import re
+import sys
+
+include_re = re.compile('^[ \t]*#include[ \t]+"(.*)"[ \t]*$')
+included = set()
+excluded = set()
+
+def find_header(name, abs_path, include_paths):
+    samedir = path.join(path.dirname(abs_path), name)
+    if path.exists(samedir):
+        return samedir
+    for include_path in include_paths:
+        include_path = path.join(include_path, name)
+        if path.exists(include_path):
+            return include_path
+    return None
+
+def expand_include(include_path, f, abs_path, source_out, header_out, include_paths, public_include_paths):
+    if include_path in included:
+        return False
+
+    included.add(include_path)
+    with open(include_path) as f:
+        print('#line 1 "{}"'.format(include_path), file=source_out)
+        process_file(f, include_path, source_out, header_out, include_paths, public_include_paths)
+    return True
+
+def process_file(f, abs_path, source_out, header_out, include_paths, public_include_paths):
+    for (line, text) in enumerate(f):
+        m = include_re.match(text)
+        if m:
+            filename = m.groups()[0]
+            # first check private headers
+            include_path = find_header(filename, abs_path, include_paths)
+            if include_path:
+                if include_path in excluded:
+                    source_out.write(text)
+                    expanded = False
+                else:
+                    expanded = expand_include(include_path, f, abs_path, source_out, header_out, include_paths, public_include_paths)
+            else:
+                # now try public headers
+                include_path = find_header(filename, abs_path, public_include_paths)
+                if include_path:
+                    # found public header
+                    expanded = False
+                    if include_path in excluded:
+                        source_out.write(text)
+                    else:
+                        expand_include(include_path, f, abs_path, header_out, None, public_include_paths, [])
+                else:
+                    sys.exit("unable to find {}, included in {} on line {}".format(filename, abs_path, line))
+
+            if expanded:
+                print('#line {} "{}"'.format(line+1, abs_path), file=source_out)
+        elif text != "#pragma once\n":
+            source_out.write(text)
+
+def main():
+    parser = argparse.ArgumentParser(description="Transform a unity build into an amalgamation")
+    parser.add_argument("source", help="source file")
+    parser.add_argument("-I", action="append", dest="include_paths", help="include paths for private headers")
+    parser.add_argument("-i", action="append", dest="public_include_paths", help="include paths for public headers")
+    parser.add_argument("-x", action="append", dest="excluded", help="excluded header files")
+    parser.add_argument("-o", dest="source_out", help="output C++ file", required=True)
+    parser.add_argument("-H", dest="header_out", help="output C++ header file", required=True)
+    args = parser.parse_args()
+
+    include_paths = list(map(path.abspath, args.include_paths or []))
+    public_include_paths = list(map(path.abspath, args.public_include_paths or []))
+    excluded.update(map(path.abspath, args.excluded or []))
+    filename = args.source
+    abs_path = path.abspath(filename)
+    with open(filename) as f, open(args.source_out, 'w') as source_out, open(args.header_out, 'w') as header_out:
+        print('#line 1 "{}"'.format(filename), file=source_out)
+        print('#include "{}"'.format(header_out.name), file=source_out)
+        process_file(f, abs_path, source_out, header_out, include_paths, public_include_paths)
+
+if __name__ == "__main__":
+    main()