Fixed bug where an empty version string is considered valid.

base/version.cc

Index: base/version.cc
diff --git a/base/version.cc b/base/version.cc
index 83dda50b62b25718ca56b0b423f854c18402a4cc..2271fcf33cced60bcef0dc71ee358382f154083d 100644
--- a/base/version.cc
+++ b/base/version.cc
@@ -2,10 +2,10 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include <vector>
+#include "base/version.h"
 
+#include "base/logging.h"
 #include "base/string_util.h"
-#include "base/version.h"
 
 // static
 Version* Version::GetVersionFromString(const std::wstring& version_str) {
@@ -17,38 +17,46 @@ Version* Version::GetVersionFromString(const std::wstring& version_str) {
 // static
 Version* Version::GetVersionFromString(const std::string& version_str) {
   Version* vers = new Version();
-  if (vers->InitFromString(version_str))
+  if (vers->InitFromString(version_str)) {
+    DCHECK(vers->is_valid_);
     return vers;
+  }
   delete vers;
   return NULL;
 }
 
+Version::Version() : is_valid_(false) {}
+
 bool Version::Equals(const Version& that) const {
+  DCHECK(is_valid_);
+  DCHECK(that.is_valid_);
   return CompareTo(that) == 0;
 }
 
 int Version::CompareTo(const Version& other) const {
-  std::vector<uint16> other_components = other.components();
-  size_t count = std::min(components_.size(), other_components.size());
+  DCHECK(is_valid_);
+  DCHECK(other.is_valid_);
+  size_t count = std::min(components_.size(), other.components_.size());
   for (size_t i = 0; i < count; ++i) {
-    if (components_[i] > other_components[i])
+    if (components_[i] > other.components_[i])
       return 1;
-    if (components_[i] < other_components[i])
+    if (components_[i] < other.components_[i])
       return -1;
   }
-  if (components_.size() > other_components.size()) {
+  if (components_.size() > other.components_.size()) {
     for (size_t i = count; i < components_.size(); ++i)
       if (components_[i] > 0)
         return 1;
-  } else if (components_.size() < other_components.size()) {
-    for (size_t i = count; i < other_components.size(); ++i)
-      if (other_components[i] > 0)
+  } else if (components_.size() < other.components_.size()) {
+    for (size_t i = count; i < other.components_.size(); ++i)
+      if (other.components_[i] > 0)
         return -1;
   }
   return 0;
 }
 
 const std::string Version::GetString() const {
+  DCHECK(is_valid_);
   std::string version_str;
   int count = components_.size();
   for (int i = 0; i < count - 1; ++i) {
@@ -60,8 +68,11 @@ const std::string Version::GetString() const {
 }
 
 bool Version::InitFromString(const std::string& version_str) {
+  DCHECK(!is_valid_);
   std::vector<std::string> numbers;
   SplitString(version_str, '.', &numbers);
+  if (numbers.empty())
+    return false;
   for (std::vector<std::string>::iterator i = numbers.begin();
        i != numbers.end(); ++i) {
     int num;
@@ -78,5 +89,6 @@ bool Version::InitFromString(const std::string& version_str) {
     uint16 component = static_cast<uint16>(num);
     components_.push_back(component);
   }
+  is_valid_ = true;
   return true;
 }