Add depcleaner, a dependency checking cleaner triggered by notifier

src/cleaner/Makefile.am

@@ -1,10 +1,10 @@
 AM_CPPFLAGS = $(CXX17_FLAGS) -I$(srcdir)/../util
 AM_CXXFLAGS = $(PICKY_CXXFLAGS)
 
-bin_PROGRAMS = cleaner rawcleaner
+bin_PROGRAMS = cleaner depcleaner
 
 cleaner_SOURCES = cleaner.cc
 cleaner_LDADD = ../util/libutil.a -lstdc++fs
 
-rawcleaner_SOURCES = rawcleaner.cc
-rawcleaner_LDADD = ../util/libutil.a -lstdc++fs
+depcleaner_SOURCES = depcleaner.cc
+depcleaner_LDADD = ../util/libutil.a -lstdc++fs

src/cleaner/depcleaner.cc

@@ -0,0 +1,67 @@
+#include <sys/stat.h>
+#include <iostream>
+#include <string>
+#include <vector>
+#include <system_error>
+
+#include "filesystem.hh"
+#include "tokenize.hh"
+#include "exception.hh"
+
+using namespace std;
+
+void print_usage(const string & program_name)
+{
+  cerr <<
+  "Usage: " << program_name << " <input_file> <remove_dir> <remove_ext> [depdir1 [depdir2 [depdir3] ...]]\n\n"
+  "<input_file>   input file from notifier\n"
+  "<remove_dir>   output dir from notifier\n"
+  "<remove_ext>   extension of the file to remove if all downstream dependencies exist\n"
+  "[depdir ... ]  directories containing dependent files"
+  << endl;
+}
+
+string get_file_basename(const string & path) {
+  vector<string> parts = split(path, "/");
+  return parts[parts.size() - 1];
+}
+
+int main(int argc, char * argv[])
+{
+  if (argc < 5) {
+    print_usage("depcleaner");
+    return EXIT_FAILURE;
+  }
+
+  string input_file, remove_dir, remove_ext;
+  input_file = argv[1];
+  remove_dir = argv[2];
+  remove_ext = argv[3];
+
+  if (!fs::exists(remove_dir)) {
+    cerr << "Output directory does not exist " << remove_dir << endl;
+    return EXIT_FAILURE;
+  }
+
+  string input_file_basename = get_file_basename(input_file);
+
+  for (int i = 4; i < argc; i++) {
+    string dependent_dir = argv[i];
+    string dependent_file = string(dependent_dir) + "/" + input_file_basename;
+    if (!fs::exists(dependent_file)) {
+      /* one of the dependent files does not exist yet so we do nothing */
+      return EXIT_SUCCESS;
+    }
+  }
+
+  string input_file_no_ext = split_filename(input_file_basename).first;
+
+  /* all of the downstream files exist so we can remove the upstream files */
+  string file_to_remove = remove_dir + "/" + input_file_no_ext + "." + remove_ext;
+  error_code ec;
+  if (not fs::remove(file_to_remove, ec) or ec) {
+    cerr << "Warning: file " << file_to_remove << " cannot be removed" << endl;
+  }
+
+  return EXIT_SUCCESS;
+}