base: Support command line wrappers with quoted arguments

Command line wrappers (e.g., --renderer-cmd-prefix) were previously
split into individual arguments purely based on whitespace. This fails
if the prefix has arguments with embedded whitespace (e.g., gdb -ex "set
height 0").

This patch fixes the issue by tokenizing the prefix based on whitespace
while using ' and " as quote characters.

BUG=546953

Review-Url: https://codereview.chromium.org/2778173003
Cr-Commit-Position: refs/heads/master@{#460443}

base/command_line.cc

@@ -11,6 +11,7 @@
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/strings/string_split.h"
+#include "base/strings/string_tokenizer.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "build/build_config.h"
@@ -411,11 +412,15 @@ void CommandLine::AppendArguments(const CommandLine& other,
 void CommandLine::PrependWrapper(const CommandLine::StringType& wrapper) {
   if (wrapper.empty())
     return;
-  // The wrapper may have embedded arguments (like "gdb --args"). In this case,
-  // we don't pretend to do anything fancy, we just split on spaces.
-  StringVector wrapper_argv = SplitString(
-      wrapper, FilePath::StringType(1, ' '), base::TRIM_WHITESPACE,
-      base::SPLIT_WANT_ALL);
+  // Split the wrapper command based on whitespace (with quoting).
+  using CommandLineTokenizer =
+      StringTokenizerT<StringType, StringType::const_iterator>;
+  CommandLineTokenizer tokenizer(wrapper, FILE_PATH_LITERAL(" "));
+  tokenizer.set_quote_chars(FILE_PATH_LITERAL("'\""));
+  std::vector<StringType> wrapper_argv;
+  while (tokenizer.GetNext())
+    wrapper_argv.emplace_back(tokenizer.token());
+
   // Prepend the wrapper and update the switches/arguments |begin_args_|.
   argv_.insert(argv_.begin(), wrapper_argv.begin(), wrapper_argv.end());
   begin_args_ += wrapper_argv.size();

base/command_line_unittest.cc

@@ -406,4 +406,35 @@ TEST(CommandLineTest, Copy) {
     EXPECT_TRUE(assigned.HasSwitch(pair.first));
 }
 
+TEST(CommandLineTest, PrependSimpleWrapper) {
+  CommandLine cl(FilePath(FILE_PATH_LITERAL("Program")));
+  cl.AppendSwitch("a");
+  cl.AppendSwitch("b");
+  cl.PrependWrapper(FILE_PATH_LITERAL("wrapper --foo --bar"));
+
+  EXPECT_EQ(6u, cl.argv().size());
+  EXPECT_EQ(FILE_PATH_LITERAL("wrapper"), cl.argv()[0]);
+  EXPECT_EQ(FILE_PATH_LITERAL("--foo"), cl.argv()[1]);
+  EXPECT_EQ(FILE_PATH_LITERAL("--bar"), cl.argv()[2]);
+  EXPECT_EQ(FILE_PATH_LITERAL("Program"), cl.argv()[3]);
+  EXPECT_EQ(FILE_PATH_LITERAL("--a"), cl.argv()[4]);
+  EXPECT_EQ(FILE_PATH_LITERAL("--b"), cl.argv()[5]);
+}
+
+TEST(CommandLineTest, PrependComplexWrapper) {
+  CommandLine cl(FilePath(FILE_PATH_LITERAL("Program")));
+  cl.AppendSwitch("a");
+  cl.AppendSwitch("b");
+  cl.PrependWrapper(
+      FILE_PATH_LITERAL("wrapper --foo='hello world' --bar=\"let's go\""));
+
+  EXPECT_EQ(6u, cl.argv().size());
+  EXPECT_EQ(FILE_PATH_LITERAL("wrapper"), cl.argv()[0]);
+  EXPECT_EQ(FILE_PATH_LITERAL("--foo='hello world'"), cl.argv()[1]);
+  EXPECT_EQ(FILE_PATH_LITERAL("--bar=\"let's go\""), cl.argv()[2]);
+  EXPECT_EQ(FILE_PATH_LITERAL("Program"), cl.argv()[3]);
+  EXPECT_EQ(FILE_PATH_LITERAL("--a"), cl.argv()[4]);
+  EXPECT_EQ(FILE_PATH_LITERAL("--b"), cl.argv()[5]);
+}
+
 } // namespace base