Implement target visibility in GN

tools/gn/visibility.cc

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "tools/gn/visibility.h"
+
+#include "base/strings/string_piece.h"
+#include "base/strings/string_util.h"
+#include "tools/gn/err.h"
+#include "tools/gn/filesystem_utils.h"
+#include "tools/gn/item.h"
+#include "tools/gn/label.h"
+#include "tools/gn/scope.h"
+#include "tools/gn/value.h"
+#include "tools/gn/variables.h"
+
+Visibility::VisPattern::VisPattern() : type_(MATCH) {
+}
+
+Visibility::VisPattern::VisPattern(Type type,
+                                   const SourceDir& dir,
+                                   const base::StringPiece& name)
+    : type_(type),
+      dir_(dir) {
+  name.CopyToString(&name_);
+}
+
+Visibility::VisPattern::~VisPattern() {
+}
+
+bool Visibility::VisPattern::Matches(const Label& label) const {
+  switch (type_) {
+    case MATCH:
+      return label.name() == name_ && label.dir() == dir_;
+    case DIRECTORY:
+      // The directories must match exactly for private visibility.
+      return label.dir() == dir_;
+    case RECURSIVE_DIRECTORY:
+      // Our directory must be a prefix of the input label for recursive
+      // private visibility.
+      return label.dir().value().compare(0, dir_.value().size(), dir_.value())
+          == 0;
+    default:
+      NOTREACHED();
+      return false;
+  }
+}
+
+Visibility::Visibility() {
+}
+
+Visibility::~Visibility() {
+}
+
+bool Visibility::Set(const SourceDir& current_dir,
+                     const Value& value,
+                     Err* err) {
+  patterns_.clear();
+
+  // Allow a single string to be passed in to make the common case (just one
+  // pattern) easier to specify.
+  if (value.type() == Value::STRING) {
+    patterns_.push_back(GetPattern(current_dir, value, err));
+    return !err->has_error();
+  }
+
+  // If it's not a string, it should be a list of strings.
+  if (!value.VerifyTypeIs(Value::LIST, err))
+    return false;
+
+  const std::vector<Value>& list = value.list_value();
+  for (size_t i = 0; i < list.size(); i++) {
+    patterns_.push_back(GetPattern(current_dir, list[i], err));
+    if (err->has_error())
+      return false;
+  }
+  return true;
+}
+
+void Visibility::SetPublic() {
+  patterns_.push_back(
+      VisPattern(VisPattern::RECURSIVE_DIRECTORY, SourceDir(), std::string()));
+}
+
+void Visibility::SetPrivate(const SourceDir& current_dir) {
+  patterns_.push_back(
+      VisPattern(VisPattern::DIRECTORY, current_dir, std::string()));
+}
+
+bool Visibility::CanSeeMe(const Label& label) const {
+  for (size_t i = 0; i < patterns_.size(); i++) {
+    if (patterns_[i].Matches(label))
+      return true;
+  }
+  return false;
+}
+
+std::string Visibility::Describe() const {
+  if (patterns_.empty())
+    return std::string("[] (no visibility)");
+  std::string result = "[\n";
+
+  for (size_t i = 0; i < patterns_.size(); i++) {
+    switch (patterns_[i].type()) {
+      case VisPattern::MATCH:
+        result += "  " + patterns_[i].dir().value() + ":" +
+            patterns_[i].name() + "\n";
+        break;
+      case VisPattern::DIRECTORY:
+        result += "  " + DirectoryWithNoLastSlash(patterns_[i].dir()) +
+            ":*\n";
+        break;
+      case VisPattern::RECURSIVE_DIRECTORY:
+        result += "  " + patterns_[i].dir().value() + "*\n";
+        break;
+    }
+  }
+
+  result += "]";
+  return result;
+}
+
+// static
+Visibility::VisPattern Visibility::GetPattern(const SourceDir& current_dir,
+                                              const Value& value,
+                                              Err* err) {
+  if (!value.VerifyTypeIs(Value::STRING, err))
+    return VisPattern();
+
+  const std::string& str = value.string_value();
+  if (str.empty()) {
+    *err = Err(value, "Visibility pattern must not be empty.");
+    return VisPattern();
+  }
+
+  // If there's no wildcard, this is specifying an exact label, use the
+  // label resolution code to get all the implicit name stuff.
+  size_t star = str.find('*');
+  if (star == std::string::npos) {
+    Label label = Label::Resolve(current_dir, Label(), value, err);
+    if (err->has_error())
+      return VisPattern();
+
+    // There should be no toolchain specified.
+    if (!label.toolchain_dir().is_null() || !label.toolchain_name().empty()) {
+      *err = Err(value, "Visibility label specified a toolchain.",
+          "Visibility names and patterns don't use toolchains, erase the\n"
+          "stuff in the ().");
+      return VisPattern();
+    }
+
+    return VisPattern(VisPattern::MATCH, label.dir(), label.name());
+  }
+
+  // Wildcard case, need to split apart the label to see what it specifies.
+  base::StringPiece path;
+  base::StringPiece name;
+  size_t colon = str.find(':');
+  if (colon == std::string::npos) {
+    path = base::StringPiece(str);
+  } else {
+    path = base::StringPiece(&str[0], colon);
+    name = base::StringPiece(&str[colon + 1], str.size() - colon - 1);
+  }
+
+  // The path can have these forms:
+  //   1. <empty>  (use current dir)
+  //   2. <non wildcard stuff>  (send through directory resolution)
+  //   3. <non wildcard stuff>*  (send stuff through dir resolution, note star)
+  //   4. *  (matches anything)
+  SourceDir dir;
+  bool has_path_star = false;
+  if (path.empty()) {
+    // Looks like ":foo".
+    dir = current_dir;
+  } else if (path[path.size() - 1] == '*') {
+    // Case 3 or 4 above.
+    has_path_star = true;
+
+    // Adjust path to contain everything but the star.
+    path = path.substr(0, path.size() - 1);
+
+    if (!path.empty() && path[path.size() - 1] != '/') {
+      // The input was "foo*" which is invalid.
+      *err = Err(value, "'*' must match full directories in visibility.",
+          "You did \"foo*\" but visibility doesn't do general pattern\n"
+          "matching. Instead, you have to add a slash: \"foo/*\".");
+      return VisPattern();
+    }
+  }
+
+  // Resolve the part of the path that's not the wildcard.
+  if (!path.empty()) {
+    // The non-wildcard stuff better not have a wildcard.
+    if (path.find('*') != base::StringPiece::npos) {
+      *err = Err(value, "Visibility patterns only support wildcard suffixes.",
+          "The visibility pattern contained a '*' that wasn't at tne end.");
+      return VisPattern();
+    }
+
+    // Resolve the non-wildcard stuff.
+    dir = current_dir.ResolveRelativeDir(path);
+    if (dir.is_null()) {
+      *err = Err(value, "Visibility pattern didn't resolve to a dir.",
+          "The directory name \"" + path.as_string() + "\" didn't\n"
+          "resolve to a directory.");
+      return VisPattern();
+    }
+  }
+
+  // Resolve the name. At this point, we're doing wildcard matches so the
+  // name should either be empty ("foo/*") or a wildcard ("foo:*");
+  if (colon != std::string::npos && name != "*") {
+    *err = Err(value, "Invalid visibility pattern.",
+        "You seem to be using the wildcard more generally that is supported.\n"
+        "Did you mean \"foo:*\" to match everything in the current file, or\n"
+        "\"./*\" to recursively match everything in the currend subtree.");
+    return VisPattern();
+  }
+
+  VisPattern::Type type;
+  if (has_path_star) {
+    // We know there's a wildcard, so if the name is empty it looks like
+    // "foo/*".
+    type = VisPattern::RECURSIVE_DIRECTORY;
+  } else {
+    // Everything else should be of the form "foo:*".
+    type = VisPattern::DIRECTORY;
+  }
+
+  // When we're doing wildcard matching, the name is always empty.
+  return VisPattern(type, dir, base::StringPiece());
+}
+
+// static
+bool Visibility::CheckItemVisibility(const Item* from,
+                                     const Item* to,
+                                     Err* err) {
+  if (!to->visibility().CanSeeMe(from->label())) {
+    std::string to_label = to->label().GetUserVisibleName(false);
+    *err = Err(from->defined_from(), "Dependency not allowed.",
+        "The item " + from->label().GetUserVisibleName(false) + "\n"
+        "can not depend on " + to_label + "\n"
+        "because it is not in " + to_label + "'s visibility list: " +
+        to->visibility().Describe());
+    return false;
+  }
+  return true;
+}
+
+// static
+bool Visibility::FillItemVisibility(Item* item, Scope* scope, Err* err) {
+  const Value* vis_value = scope->GetValue(variables::kVisibility, true);
+  if (vis_value)
+    item->visibility().Set(scope->GetSourceDir(), *vis_value, err);
+  else  // Default to public.
+    item->visibility().SetPublic();
+  return !err->has_error();
+}