Add a tool to export a kati stamp file to other tools

There's a desire to understand which files are used by a build so that
the automated builds can make better guesses at which builds should be
run for a certain change. Instead of having them read a stamp file
directly, which would prevent us from updating the stamp format in the
future, build a tool that can be used to export the contents in a stable
and more portable format.

Right now, this just means exporting the file list to stdout with
newlines as delimiters. An idea for the future is to define a protobuf
or similar format that would contain the glob and shell information as
well (if it's useful).

1 files changed, 57 insertions, 0 deletions

diff --git a/regen_dump.cc b/regen_dump.cc
new file mode 100644
index 0000000..9838ab5
--- /dev/null
+++ b/regen_dump.cc
@@ -0,0 +1,57 @@
+// Copyright 2016 Google Inc. All rights reserved
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build ignore
+
+// This command will dump the contents of a kati stamp file into a more portable
+// format for use by other tools. For now, it just exports the files read.
+// Later, this will be expanded to include the Glob and Shell commands, but
+// those require a more complicated output format.
+
+#include <stdio.h>
+
+#include <string>
+
+#include "io.h"
+#include "log.h"
+#include "strutil.h"
+
+int main(int argc, char* argv[]) {
+  if (argc == 1) {
+    fprintf(stderr, "Usage: ckati_stamp_dump <stamp>\n");
+    return 1;
+  }
+
+  FILE *fp = fopen(argv[1], "rb");
+  if(!fp)
+    PERROR("fopen");
+
+  ScopedFile sfp(fp);
+  double gen_time;
+  size_t r = fread(&gen_time, sizeof(gen_time), 1, fp);
+  if (r != 1)
+    ERROR("Incomplete stamp file");
+
+  int num_files = LoadInt(fp);
+  if (num_files < 0)
+    ERROR("Incomplete stamp file");
+  for (int i = 0; i < num_files; i++) {
+    string s;
+    if (!LoadString(fp, s))
+      ERROR("Incomplete stamp file");
+    printf("%s\n", s.c_str());
+  }
+
+  return 0;
+}