Fourth attempt at the following. Unreviewed, this was originally reviewed in http://codereview.c...

net/base/ssl_false_start_blacklist_process.cc

Index: net/base/ssl_false_start_blacklist_process.cc
===================================================================
--- net/base/ssl_false_start_blacklist_process.cc	(revision 101373)
+++ net/base/ssl_false_start_blacklist_process.cc	(working copy)
@@ -5,116 +5,115 @@
 // This utility program exists to process the False Start blacklist file into
 // a static hash table so that it can be efficiently queried by Chrome.
 
-#include <stdio.h>
-#include <stdlib.h>
-
+#include <algorithm>
+#include <cstdio>
 #include <set>
+#include <sstream>
 #include <string>
 #include <vector>
 
 #include "base/basictypes.h"
+#include "base/file_util.h"
+#include "base/string_util.h"
 #include "net/base/ssl_false_start_blacklist.h"
 
-using net::SSLFalseStartBlacklist;
+typedef std::vector<std::string> Hosts;
 
-static const unsigned kBuckets = SSLFalseStartBlacklist::kBuckets;
-
-static bool verbose = false;
-
-static int
-usage(const char* argv0) {
-  fprintf(stderr, "Usage: %s <blacklist file> <output .c file>\n", argv0);
-  return 1;
-}
-
-// StripWWWPrefix removes "www." from the beginning of any elements of the
-// vector.
-static void StripWWWPrefix(std::vector<std::string>* hosts) {
-  static const char kPrefix[] = "www.";
-  static const unsigned kPrefixLen = sizeof(kPrefix) - 1;
-
-  for (size_t i = 0; i < hosts->size(); i++) {
-    const std::string& h = (*hosts)[i];
-    if (h.size() >= kPrefixLen &&
-        memcmp(h.data(), kPrefix, kPrefixLen) == 0) {
-      (*hosts)[i] = h.substr(kPrefixLen, h.size() - kPrefixLen);
+// Parses |input| as a blacklist data file, and returns the set of hosts it
+// contains.
+Hosts ParseHosts(const std::string& input) {
+  Hosts hosts;
+  size_t line_start = 0;
+  bool is_comment = false;
+  bool non_whitespace_seen = false;
+  for (size_t i = 0; i <= input.size(); ++i) {
+    if (i == input.size() || input[i] == '\n') {
+      if (!is_comment && non_whitespace_seen) {
+        size_t len = i - line_start;
+        if (i > 0 && input[i - 1] == '\r')
+          len--;
+        hosts.push_back(input.substr(line_start, len));
+      }
+      is_comment = false;
+      non_whitespace_seen = false;
+      line_start = i + 1;
+    } else if (input[i] != ' ' && input[i] != '\t' && input[i] != '\r') {
+      non_whitespace_seen = true;
+      if (i == line_start && input[i] == '#')
+        is_comment = true;
     }
   }
+  VLOG(1) << "Have " << hosts.size() << " hosts after parse";
+  return hosts;
 }
 
-// RemoveDuplicateEntries removes all duplicates from |hosts|.
+// Returns |host| with any initial "www." and trailing dots removed.  Partly
+// based on net::StripWWW().
+std::string StripWWWAndTrailingDots(const std::string& host) {
+  const std::string www("www.");
+  const size_t start = StartsWithASCII(host, www, true) ? www.length() : 0;
+  const size_t end = host.find_last_not_of('.');
+  return (end == std::string::npos) ?
+      std::string() : host.substr(start, end - start + 1);
+}
+
+// Removes all duplicates from |hosts|.
 static void RemoveDuplicateEntries(std::vector<std::string>* hosts) {
-  std::set<std::string> hosts_set;
-  std::vector<std::string> ret;
+  std::sort(hosts->begin(), hosts->end());
+  hosts->erase(std::unique(hosts->begin(), hosts->end()), hosts->end());
+  VLOG(1) << "Have " << hosts->size() << " hosts after removing duplicates";
+}
 
-  for (std::vector<std::string>::const_iterator
-       i = hosts->begin(); i != hosts->end(); i++) {
-    if (hosts_set.count(*i)) {
-      if (verbose)
-        fprintf(stderr, "Removing duplicate entry for %s\n", i->c_str());
-      continue;
-    }
-    hosts_set.insert(*i);
-    ret.push_back(*i);
-  }
-
-  hosts->swap(ret);
+// Returns the parent domain for |host|, or the empty string if the name is a
+// top-level domain.
+static std::string ParentDomain(const std::string& host) {
+  const size_t first_dot = host.find('.');
+  return (first_dot == std::string::npos) ?
+      std::string() : host.substr(first_dot + 1);
 }
 
-// ParentDomain returns the parent domain for a given domain name or the empty
-// string if the name is a top-level domain.
-static std::string ParentDomain(const std::string& in) {
-  for (size_t i = 0; i < in.size(); i++) {
-    if (in[i] == '.') {
-      return in.substr(i + 1, in.size() - i - 1);
+// Predicate which returns true when a hostname has a parent domain in the set
+// of hosts provided at construction time.
+class ParentInSet : public std::unary_function<std::string, bool> {
+ public:
+  explicit ParentInSet(const std::set<std::string>& hosts) : hosts_(hosts) {}
+
+  bool operator()(const std::string& host) const {
+    for (std::string parent(ParentDomain(host)); !parent.empty();
+         parent = ParentDomain(parent)) {
+      if (hosts_.count(parent)) {
+        VLOG(1) << "Removing " << host << " as redundant";
+        return true;
+      }
     }
+    return false;
   }
 
-  return std::string();
-}
+ private:
+  const std::set<std::string>& hosts_;
+};
 
-// RemoveRedundantEntries removes any entries which are subdomains of other
-// entries. (i.e. foo.example.com would be removed if example.com were also
-// included.)
-static void RemoveRedundantEntries(std::vector<std::string>* hosts) {
+// Removes any hosts which are subdomains of other hosts.  E.g.
+// "foo.example.com" would be removed if "example.com" were also included.
+static void RemoveRedundantEntries(Hosts* hosts) {
   std::set<std::string> hosts_set;
-  std::vector<std::string> ret;
-
-  for (std::vector<std::string>::const_iterator
-       i = hosts->begin(); i != hosts->end(); i++) {
+  for (Hosts::const_iterator i(hosts->begin()); i != hosts->end(); ++i)
     hosts_set.insert(*i);
-  }
-
-  for (std::vector<std::string>::const_iterator
-       i = hosts->begin(); i != hosts->end(); i++) {
-    std::string parent = ParentDomain(*i);
-    while (!parent.empty()) {
-      if (hosts_set.count(parent))
-        break;
-      parent = ParentDomain(parent);
-    }
-    if (parent.empty()) {
-      ret.push_back(*i);
-    } else {
-      if (verbose)
-        fprintf(stderr, "Removing %s as redundant\n", i->c_str());
-    }
-  }
-
-  hosts->swap(ret);
+  hosts->erase(std::remove_if(hosts->begin(), hosts->end(),
+                              ParentInSet(hosts_set)), hosts->end());
+  VLOG(1) << "Have " << hosts->size() << " hosts after removing redundants";
 }
 
-// CheckLengths returns true iff every host is less than 256 bytes long (not
-// including the terminating NUL) and contains two or more labels.
-static bool CheckLengths(const std::vector<std::string>& hosts) {
-  for (std::vector<std::string>::const_iterator
-       i = hosts.begin(); i != hosts.end(); i++) {
+// Returns true iff all |hosts| are less than 256 bytes long (not including the
+// terminating NUL) and contain two or more dot-separated components.
+static bool CheckLengths(const Hosts& hosts) {
+  for (Hosts::const_iterator i(hosts.begin()); i != hosts.end(); ++i) {
      if (i->size() >= 256) {
-       fprintf(stderr, "Entry %s is too large\n", i->c_str());
+       fprintf(stderr, "Entry '%s' is too large\n", i->c_str());
        return false;
      }
-     if (SSLFalseStartBlacklist::LastTwoLabels(i->c_str()) == NULL) {
-       fprintf(stderr, "Entry %s contains too few labels\n", i->c_str());
+     if (net::SSLFalseStartBlacklist::LastTwoComponents(*i).empty()) {
+       fprintf(stderr, "Entry '%s' contains too few labels\n", i->c_str());
        return false;
      }
   }
@@ -122,150 +121,94 @@
   return true;
 }
 
-int main(int argc, char** argv) {
-  if (argc != 3)
-    return usage(argv[0]);
-
-  const char* input_file = argv[1];
-  const char* output_file = argv[2];
-  FILE* input = fopen(input_file, "rb");
-  if (!input) {
-    perror("open");
-    return usage(argv[0]);
+// Returns the contents of the output file to be written.
+std::string GenerateOutput(const Hosts& hosts) {
+  // Hash each host into its appropriate bucket.
+  VLOG(1) << "Using " << net::SSLFalseStartBlacklist::kBuckets
+          << " entry hash table";
+  Hosts buckets[net::SSLFalseStartBlacklist::kBuckets];
+  for (Hosts::const_iterator i(hosts.begin()); i != hosts.end(); ++i) {
+    const uint32 hash = net::SSLFalseStartBlacklist::Hash(
+        net::SSLFalseStartBlacklist::LastTwoComponents(*i));
+    buckets[hash & (net::SSLFalseStartBlacklist::kBuckets - 1)].push_back(*i);
   }
 
-  if (fseek(input, 0, SEEK_END)) {
-    perror("fseek");
-    return 1;
-  }
+  // Write header.
+  std::ostringstream output;
+  output << "// Copyright (c) 2011 The Chromium Authors. All rights reserved.\n"
+            "// Use of this source code is governed by a BSD-style license that"
+            " can be\n// found in the LICENSE file.\n\n// WARNING: This code is"
+            " generated by ssl_false_start_blacklist_process.cc.\n// Do not "
+            "edit.\n\n#include \"net/base/ssl_false_start_blacklist.h\"\n\n"
+            "namespace net {\n\nconst uint32 "
+            "SSLFalseStartBlacklist::kHashTable["
+         << net::SSLFalseStartBlacklist::kBuckets << " + 1] = {\n  0,\n";
 
-  const long input_size = ftell(input);
-  if (input_size < 0) {
-    perror("ftell");
-    return 1;
-  }
-
-  if (fseek(input, 0, SEEK_SET)) {
-    perror("fseek");
-    return 1;
-  }
-
-  char* buffer = static_cast<char*>(malloc(input_size));
-  long done = 0;
-  while (done < input_size) {
-    size_t n = fread(buffer + done, 1, input_size - done, input);
-    if (n == 0) {
-      perror("fread");
-      free(buffer);
-      fclose(input);
-      return 1;
-    }
-    done += n;
-  }
-  fclose(input);
-
-  std::vector<std::string> hosts;
-
-  off_t line_start = 0;
-  bool is_comment = false;
-  bool non_whitespace_seen = false;
-  for (long i = 0; i <= input_size; i++) {
-    if (i == input_size || buffer[i] == '\n') {
-      if (!is_comment && non_whitespace_seen) {
-        long len = i - line_start;
-        if (i > 0 && buffer[i-1] == '\r')
-          len--;
-        hosts.push_back(std::string(&buffer[line_start], len));
-      }
-      is_comment = false;
-      non_whitespace_seen = false;
-      line_start = i + 1;
-      continue;
-    }
-
-    if (i == line_start && buffer[i] == '#')
-      is_comment = true;
-    if (buffer[i] != ' ' && buffer[i] != '\t' && buffer[i] != '\r')
-      non_whitespace_seen = true;
-  }
-  free(buffer);
-
-  fprintf(stderr, "Have %d hosts after parse\n", (int) hosts.size());
-  StripWWWPrefix(&hosts);
-  RemoveDuplicateEntries(&hosts);
-  fprintf(stderr, "Have %d hosts after removing duplicates\n", (int) hosts.size());
-  RemoveRedundantEntries(&hosts);
-  fprintf(stderr, "Have %d hosts after removing redundants\n", (int) hosts.size());
-  if (!CheckLengths(hosts)) {
-    fprintf(stderr, "One or more entries is too large or too small\n");
-    return 2;
-  }
-
-  fprintf(stderr, "Using %d entry hash table\n", kBuckets);
-  uint32 table[kBuckets];
-  std::vector<std::string> buckets[kBuckets];
-
-  for (std::vector<std::string>::const_iterator
-       i = hosts.begin(); i != hosts.end(); i++) {
-    const char* last_two_labels =
-        SSLFalseStartBlacklist::LastTwoLabels(i->c_str());
-    const unsigned h = SSLFalseStartBlacklist::Hash(last_two_labels);
-    buckets[h & (kBuckets - 1)].push_back(*i);
-  }
-
+  // Construct data table, writing out the size as each bucket is appended.
   std::string table_data;
-  unsigned max_bucket_size = 0;
-  for (unsigned i = 0; i < kBuckets; i++) {
-    if (buckets[i].size() > max_bucket_size)
-      max_bucket_size = buckets[i].size();
-
-    table[i] = table_data.size();
-    for (std::vector<std::string>::const_iterator
-         j = buckets[i].begin(); j != buckets[i].end(); j++) {
-      table_data.push_back((char) j->size());
+  size_t max_bucket_size = 0;
+  for (size_t i = 0; i < net::SSLFalseStartBlacklist::kBuckets; i++) {
+    max_bucket_size = std::max(max_bucket_size, buckets[i].size());
+    for (Hosts::const_iterator j(buckets[i].begin()); j != buckets[i].end();
+         ++j) {
+      table_data.push_back(static_cast<char>(j->size()));
       table_data.append(*j);
     }
+    output << "  " << table_data.size() << ",\n";
   }
+  output << "};\n\n";
+  VLOG(1) << "Largest bucket has " << max_bucket_size << " entries";
 
-  fprintf(stderr, "Largest bucket has %d entries\n", max_bucket_size);
-
-  FILE* out = fopen(output_file, "w+");
-  if (!out) {
-    perror("opening output file");
-    return 4;
-  }
-
-  fprintf(out, "// Copyright (c) 2010 The Chromium Authors. All rights "
-          "reserved.\n// Use of this source code is governed by a BSD-style "
-          "license that can be\n// found in the LICENSE file.\n\n");
-  fprintf(out, "// WARNING: this code is generated by\n"
-               "// ssl_false_start_blacklist_process.cc. Do not edit.\n\n");
-  fprintf(out, "#include \"base/basictypes.h\"\n\n");
-  fprintf(out, "#include \"net/base/ssl_false_start_blacklist.h\"\n\n");
-  fprintf(out, "namespace net {\n\n");
-  fprintf(out, "const uint32 SSLFalseStartBlacklist::kHashTable[%d + 1] = {\n",
-          kBuckets);
-  for (unsigned i = 0; i < kBuckets; i++) {
-    fprintf(out, "  %u,\n", (unsigned) table[i]);
-  }
-  fprintf(out, "  %u,\n", (unsigned) table_data.size());
-  fprintf(out, "};\n\n");
-
-  fprintf(out, "const char SSLFalseStartBlacklist::kHashData[] = {\n");
-  for (unsigned i = 0, line_length = 0; i < table_data.size(); i++) {
+  // Write data table, breaking lines after 72+ (2 indent, 70+ data) characters.
+  output << "const char SSLFalseStartBlacklist::kHashData[] = {\n";
+  for (size_t i = 0, line_length = 0; i < table_data.size(); i++) {
     if (line_length == 0)
-      fprintf(out, "  ");
-    uint8 c = static_cast<uint8>(table_data[i]);
-    line_length += fprintf(out, "%d, ", c);
+      output << "  ";
+    std::ostringstream::pos_type current_length = output.tellp();
+    output << static_cast<int>(table_data[i]) << ", ";
+    line_length += output.tellp() - current_length;
     if (i == table_data.size() - 1) {
-      fprintf(out, "\n};\n");
+      output << "\n};\n";
     } else if (line_length >= 70) {
-      fprintf(out, "\n");
+      output << "\n";
       line_length = 0;
     }
   }
-  fprintf(out, "\n}  // namespace net\n");
-  fclose(out);
+  output << "\n}  // namespace net\n";
+  return output.str();
+}
 
-  return 0;
+#if defined(OS_WIN)
+int wmain(int argc, wchar_t* argv[], wchar_t* envp[]) {
+#elif defined(OS_POSIX)
+int main(int argc, char* argv[], char* envp[]) {
+#endif
+  if (argc != 3) {
+    fprintf(stderr, "Usage: %s <blacklist file> <output .c file>\n", argv[0]);
+    return 1;
+  }
+
+  // Read input file.
+  std::string input;
+  if (!file_util::ReadFileToString(FilePath(argv[1]), &input)) {
+    fprintf(stderr, "Failed to read input file '%s'\n", argv[1]);
+    return 2;
+  }
+  Hosts hosts(ParseHosts(input));
+
+  // Sanitize |hosts|.
+  std::transform(hosts.begin(), hosts.end(), hosts.begin(),
+                 StripWWWAndTrailingDots);
+  RemoveDuplicateEntries(&hosts);
+  RemoveRedundantEntries(&hosts);
+  if (!CheckLengths(hosts))
+    return 3;
+
+  // Write output file.
+  const std::string output_str(GenerateOutput(hosts));
+  if (file_util::WriteFile(FilePath(argv[2]), output_str.data(),
+      output_str.size()) == static_cast<int>(output_str.size()))
+    return 0;
+  fprintf(stderr, "Failed to write output file '%s'\n", argv[2]);
+  return 4;
 }