canonicalize paths loaded from depfiles

If a C file #includes "../foo.cc", then gcc will emit paths like
"bar/../foo.cc" into the dependency file; canonicalize these when we
load the file.

Add a test module for testing the graph dirty recomputation directly,
without all the build classes around it.

Author: evmar

build.ninja

@@ -50,12 +50,13 @@ build ninja: link $builddir/ninja.o $builddir/ninja.a
 
 build $builddir/build_test.o: cxx src/build_test.cc
 build $builddir/build_log_test.o: cxx src/build_log_test.cc
+build $builddir/graph_test.o: cxx src/graph_test.cc
 build $builddir/ninja_test.o: cxx src/ninja_test.cc
 build $builddir/parsers_test.o: cxx src/parsers_test.cc
 build $builddir/subprocess_test.o: cxx src/subprocess_test.cc
 build $builddir/test.o: cxx src/test.cc
 build ninja_test: link $builddir/build_test.o $builddir/build_log_test.o \
-    $builddir/ninja_test.o $builddir/parsers_test.o \
+    $builddir/graph_test.o $builddir/ninja_test.o $builddir/parsers_test.o \
     $builddir/subprocess_test.o $builddir/test.o $builddir/ninja.a
   ldflags = -g -rdynamic -lgtest -lgtest_main -lpthread
 

src/graph.cc

@@ -20,6 +20,59 @@
 #include "ninja.h"
 #include "parsers.h"
 
+// Canonicalize a path like "foo/../bar.h" into just "bar.h".
+bool CanonicalizePath(string* path, string* err) {
+  // Try to fast-path out the common case.
+  if (path->find("/.") == string::npos &&
+      path->find("./") == string::npos) {
+    return true;
+  }
+
+  string inpath = *path;
+  vector<const char*> parts;
+  for (string::size_type start = 0; start < inpath.size(); ++start) {
+    string::size_type end = inpath.find('/', start);
+    if (end == string::npos)
+      end = inpath.size();
+    else
+      inpath[end] = 0;
+    parts.push_back(inpath.data() + start);
+    start = end;
+  }
+
+  vector<const char*>::iterator i = parts.begin();
+  while (i != parts.end()) {
+    const char* part = *i;
+    if (part[0] == '.') {
+      if (part[1] == 0) {
+        // "."; strip.
+        parts.erase(i);
+        continue;
+      } else if (part[1] == '.' && part[2] == 0) {
+        // ".."; go up one.
+        if (i == parts.begin()) {
+          *err = "can't canonicalize path '" + *path + "' that reaches "
+            "above its directory";
+          return false;
+        }
+        --i;
+        parts.erase(i, i + 2);
+        continue;
+      }
+    }
+    ++i;
+  }
+  path->clear();
+
+  for (i = parts.begin(); i != parts.end(); ++i) {
+    if (!path->empty())
+      path->push_back('/');
+    path->append(*i);
+  }
+
+  return true;
+}
+
 bool FileStat::Stat(DiskInterface* disk_interface) {
   mtime_ = disk_interface->Stat(path_);
   return mtime_ > 0;
@@ -124,7 +177,8 @@ string Edge::GetDescription() {
   return rule_->description_.Evaluate(&env);
 }
 
-bool Edge::LoadDepFile(State* state, DiskInterface* disk_interface, string* err) {
+bool Edge::LoadDepFile(State* state, DiskInterface* disk_interface,
+                       string* err) {
   EdgeEnv env(this);
   string path = rule_->depfile_.Evaluate(&env);
 
@@ -155,6 +209,9 @@ bool Edge::LoadDepFile(State* state, DiskInterface* disk_interface, string* err)
   // Add all its in-edges.
   for (vector<string>::iterator i = makefile.ins_.begin();
        i != makefile.ins_.end(); ++i) {
+    if (!CanonicalizePath(&*i, err))
+      return false;
+
     Node* node = state->GetNode(*i);
     for (vector<Node*>::iterator j = inputs_.begin(); j != inputs_.end(); ++j) {
       if (*j == node) {

src/graph.h

@@ -119,4 +119,7 @@ struct Edge {
   bool is_phony() const;
 };
 
+// Exposed for testing.
+bool CanonicalizePath(string* path, string* err);
+
 #endif  // NINJA_GRAPH_H_

src/graph_test.cc

@@ -0,0 +1,90 @@
+// Copyright 2011 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.
+
+#include "graph.h"
+
+#include "test.h"
+
+TEST(CanonicalizePath, PathSamples) {
+  string path = "foo.h";
+  string err;
+  EXPECT_TRUE(CanonicalizePath(&path, &err));
+  EXPECT_EQ("", err);
+  EXPECT_EQ("foo.h", path);
+
+  path = "./foo.h"; err = "";
+  EXPECT_TRUE(CanonicalizePath(&path, &err));
+  EXPECT_EQ("", err);
+  EXPECT_EQ("foo.h", path);
+
+  path = "./foo/./bar.h"; err = "";
+  EXPECT_TRUE(CanonicalizePath(&path, &err));
+  EXPECT_EQ("", err);
+  EXPECT_EQ("foo/bar.h", path);
+
+  path = "./x/foo/../bar.h"; err = "";
+  EXPECT_TRUE(CanonicalizePath(&path, &err));
+  EXPECT_EQ("", err);
+  EXPECT_EQ("x/bar.h", path);
+
+  path = "./x/foo/../../bar.h"; err = "";
+  EXPECT_TRUE(CanonicalizePath(&path, &err));
+  EXPECT_EQ("", err);
+  EXPECT_EQ("bar.h", path);
+
+  path = "./x/../foo/../../bar.h"; err = "";
+  EXPECT_FALSE(CanonicalizePath(&path, &err));
+  EXPECT_EQ("can't canonicalize path './x/../foo/../../bar.h' that reaches "
+            "above its directory", err);
+}
+
+struct GraphTest : public StateTestWithBuiltinRules {
+  VirtualFileSystem fs_;
+};
+
+TEST_F(GraphTest, MissingImplicit) {
+  ASSERT_NO_FATAL_FAILURE(AssertParse(&state_,
+"build out: cat in | implicit\n"));
+  fs_.Create("in", 1, "");
+  fs_.Create("out", 1, "");
+
+  Edge* edge = GetNode("out")->in_edge_;
+  string err;
+  EXPECT_TRUE(edge->RecomputeDirty(&state_, &fs_, &err));
+  ASSERT_EQ("", err);
+
+  // A missing implicit dep does not make the output dirty.
+  EXPECT_FALSE(GetNode("out")->dirty_);
+}
+
+TEST_F(GraphTest, FunkyMakefilePath) {
+  ASSERT_NO_FATAL_FAILURE(AssertParse(&state_,
+"rule catdep\n"
+"  depfile = $out.d\n"
+"  command = cat $in > $out\n"
+"build out.o: catdep foo.cc\n"));
+  fs_.Create("implicit.h", 2, "");
+  fs_.Create("foo.cc", 1, "");
+  fs_.Create("out.o.d", 1, "out.o: ./foo/../implicit.h\n");
+  fs_.Create("out.o", 1, "");
+
+  Edge* edge = GetNode("out.o")->in_edge_;
+  string err;
+  EXPECT_TRUE(edge->RecomputeDirty(&state_, &fs_, &err));
+  ASSERT_EQ("", err);
+
+  // implicit.h has changed, though our depfile refers to it with a
+  // non-canonical path; we should still find it.
+  EXPECT_TRUE(GetNode("out.o")->dirty_);
+}