From ac4cc82452ec145e2f567b8edab6c14d642d41c8 Mon Sep 17 00:00:00 2001
From: Evan Martin <martine@danga.com>
Date: Sun, 19 Dec 2010 14:53:38 -0800
Subject: expand variables in build paths

---
 src/parsers.cc      | 22 ++++++++++++++++++----
 src/parsers_test.cc | 21 +++++++++++++++++++++
 2 files changed, 39 insertions(+), 4 deletions(-)

diff --git a/src/parsers.cc b/src/parsers.cc
index 4d6c058..c66b91b 100644
--- a/src/parsers.cc
+++ b/src/parsers.cc
@@ -82,7 +82,7 @@ static bool IsIdentChar(char c) {
     ('a' <= c && c <= 'z') ||
     ('+' <= c && c <= '9') ||  // +,-./ and numbers
     ('A' <= c && c <= 'Z') ||
-    (c == '_') || (c == '@');
+    (c == '_') || (c == '@') || (c == '$');
 }
 
 bool Tokenizer::ExpectToken(Token::Type expected, string* err) {
@@ -379,7 +379,7 @@ bool ManifestParser::ParseEdge(string* err) {
     string out;
     if (!tokenizer_.ReadIdent(&out))
       return tokenizer_.Error("expected output file list", err);
-    outs.push_back(ExpandFile(out));
+    outs.push_back(out);
   }
   // XXX check outs not empty
 
@@ -402,7 +402,7 @@ bool ManifestParser::ParseEdge(string* err) {
     string in;
     if (!tokenizer_.ReadIdent(&in))
       break;
-    ins.push_back(ExpandFile(in));
+    ins.push_back(in);
   }
 
   // Add all order-only deps, counting how many as we go.
@@ -413,7 +413,7 @@ bool ManifestParser::ParseEdge(string* err) {
       string in;
       if (!tokenizer_.ReadIdent(&in))
         break;
-      ins.push_back(ExpandFile(in));
+      ins.push_back(in);
       ++order_only;
     }
   }
@@ -440,6 +440,20 @@ bool ManifestParser::ParseEdge(string* err) {
     tokenizer_.ConsumeToken();
   }
 
+  // Evaluate all variables in paths.
+  // XXX: fast path skip the eval parse if there's no $ in the path?
+  vector<string>* paths[2] = { &ins, &outs };
+  for (int p = 0; p < 2; ++p) {
+    for (vector<string>::iterator i = paths[p]->begin();
+         i != paths[p]->end(); ++i) {
+      EvalString eval;
+      string eval_err;
+      if (!eval.Parse(*i, &eval_err))
+        return tokenizer_.Error(eval_err, err);
+      *i = ExpandFile(eval.Evaluate(env));
+    }
+  }
+
   Edge* edge = state_->AddEdge(rule);
   edge->env_ = env;
   for (vector<string>::iterator i = ins.begin(); i != ins.end(); ++i)
diff --git a/src/parsers_test.cc b/src/parsers_test.cc
index 6bd8e4b..f38e6dc 100644
--- a/src/parsers_test.cc
+++ b/src/parsers_test.cc
@@ -125,6 +125,17 @@ TEST_F(ParserTest, CanonicalizeFile) {
   EXPECT_FALSE(state.LookupNode("in//2"));
 }
 
+TEST_F(ParserTest, PathVariables) {
+  ASSERT_NO_FATAL_FAILURE(AssertParse(
+"rule cat\n"
+"  command = cat $in > $out\n"
+"dir = out\n"
+"build $dir/exe: cat src\n"));
+
+  EXPECT_FALSE(state.LookupNode("$dir/exe"));
+  EXPECT_TRUE(state.LookupNode("out/exe"));
+}
+
 TEST_F(ParserTest, Errors) {
   {
     ManifestParser parser(NULL, NULL);
@@ -218,6 +229,16 @@ TEST_F(ParserTest, Errors) {
                               &err));
     EXPECT_EQ("line 4, col 0: unexpected variable 'othervar'", err);
   }
+
+  {
+    State state;
+    ManifestParser parser(&state, NULL);
+    string err;
+    EXPECT_FALSE(parser.Parse("rule cc\n  command = foo\n"
+                              "build $: cc bar.cc\n",
+                              &err));
+    EXPECT_EQ("line 4, col 1: expected variable after $", err);
+  }
 }
 
 TEST_F(ParserTest, BuildDir) {
-- 
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