Implement generator rules

Introduce a rule attribute "generator" which, if present, specifies
that this rule is used to re-invoke the generator program.  Files built
using generator rules are treated specially in two ways: firstly,
they will not be rebuilt if the command line changes; and secondly,
they are not cleaned by default.

A command line flag "-g" is introduced for the clean tool, which
causes it to remove generator files.

Fixes issue #102.

1 files changed, 22 insertions, 0 deletions

diff --git a/src/clean_test.cc b/src/clean_test.cc
index f031dee..8606239 100644
--- a/src/clean_test.cc
+++ b/src/clean_test.cc
@@ -212,6 +212,28 @@ TEST_F(CleanTest, CleanRuleDryRun) {
   EXPECT_EQ(0u, fs_.files_removed_.size());
 }
 
+TEST_F(CleanTest, CleanRuleGenerator) {
+  ASSERT_NO_FATAL_FAILURE(AssertParse(&state_,
+"rule regen\n"
+"  command = cat $in > $out\n"
+"  generator = 1\n"
+"build out1: cat in1\n"
+"build out2: regen in2\n"));
+  fs_.Create("out1", 1, "");
+  fs_.Create("out2", 1, "");
+
+  Cleaner cleaner(&state_, config_, &fs_);
+  EXPECT_EQ(0, cleaner.CleanAll());
+  EXPECT_EQ(1, cleaner.cleaned_files_count());
+  EXPECT_EQ(1u, fs_.files_removed_.size());
+
+  fs_.Create("out1", 1, "");
+
+  EXPECT_EQ(0, cleaner.CleanAll(/*generator=*/true));
+  EXPECT_EQ(2, cleaner.cleaned_files_count());
+  EXPECT_EQ(2u, fs_.files_removed_.size());
+}
+
 TEST_F(CleanTest, CleanFailure) {
   ASSERT_NO_FATAL_FAILURE(AssertParse(&state_,
                                       "build dir: cat src1\n"));