Add UUID::InitializeFromString().

R=mark@chromium.org
TEST=util_test --gtest_filter=UUID.FromString

Review URL: https://codereview.chromium.org/820783004

util/misc/uuid.cc

@@ -14,6 +14,8 @@
 
 #include "util/misc/uuid.h"
 
+#include <inttypes.h>
+#include <stdio.h>
 #include <string.h>
 
 #include "base/basictypes.h"
@@ -52,6 +54,35 @@ void UUID::InitializeFromBytes(const uint8_t* bytes) {
   data_3 = base::NetToHost16(data_3);
 }
 
+bool UUID::InitializeFromString(const base::StringPiece& string) {
+  if (string.length() != 36)
+    return false;
+
+  UUID temp;
+  const char kScanFormat[] =
+      "%08" SCNx32 "-%04" SCNx16 "-%04" SCNx16
+      "-%02" SCNx8 "%02" SCNx8
+      "-%02" SCNx8 "%02" SCNx8 "%02" SCNx8 "%02" SCNx8 "%02" SCNx8 "%02" SCNx8;
+  int rv = sscanf(string.data(),
+                  kScanFormat,
+                  &temp.data_1,
+                  &temp.data_2,
+                  &temp.data_3,
+                  &temp.data_4[0],
+                  &temp.data_4[1],
+                  &temp.data_5[0],
+                  &temp.data_5[1],
+                  &temp.data_5[2],
+                  &temp.data_5[3],
+                  &temp.data_5[4],
+                  &temp.data_5[5]);
+  if (rv != 11)
+    return false;
+
+  *this = temp;
+  return true;
+}
+
 std::string UUID::ToString() const {
   return base::StringPrintf("%08x-%04x-%04x-%02x%02x-%02x%02x%02x%02x%02x%02x",
                             data_1,

util/misc/uuid.h

@@ -19,6 +19,8 @@
 
 #include <string>
 
+#include "base/strings/string_piece.h"
+
 namespace crashpad {
 
 //! \brief A universally unique identifier (%UUID).
@@ -49,6 +51,16 @@ struct UUID {
   //!     %UUID.
   void InitializeFromBytes(const uint8_t* bytes);
 
+  //! \brief Initializes the %UUID from a RFC 4122 §3 formatted string.
+  //!
+  //! \param[in] string A string of the form
+  //!     `"00112233-4455-6677-8899-aabbccddeeff"`.
+  //!
+  //! \return `true` if the string was formatted correctly and the object has
+  //!     been initialized with the data. `false` if the string could not be
+  //!     parsed, with the object state untouched.
+  bool InitializeFromString(const base::StringPiece& string);
+
   //! \brief Formats the %UUID per RFC 4122 §3.
   //!
   //! \return A string of the form `"00112233-4455-6677-8899-aabbccddeeff"`.

util/misc/uuid_test.cc

@@ -19,6 +19,7 @@
 #include <string>
 
 #include "base/basictypes.h"
+#include "base/strings/stringprintf.h"
 #include "gtest/gtest.h"
 
 namespace crashpad {
@@ -152,6 +153,56 @@ TEST(UUID, UUID) {
   EXPECT_EQ("45454545-4545-4545-4545-454545454545", uuid.ToString());
 }
 
+TEST(UUID, FromString) {
+  const struct TestCase {
+    const char* uuid_string;
+    bool success;
+  } kCases[] = {
+    // Valid:
+    {"c6849cb5-fe14-4a79-8978-9ae6034c521d", true},
+    {"00000000-0000-0000-0000-000000000000", true},
+    {"ffffffff-ffff-ffff-ffff-ffffffffffff", true},
+    // Outside HEX range:
+    {"7318z10b-c453-4cef-9dc8-015655cb4bbc", false},
+    {"7318a10b-c453-4cef-9dz8-015655cb4bbc", false},
+    // Incomplete:
+    {"15655cb4-", false},
+    {"7318f10b-c453-4cef-9dc8-015655cb4bb", false},
+    {"318f10b-c453-4cef-9dc8-015655cb4bb2", false},
+    {"7318f10b-c453-4ef-9dc8-015655cb4bb2", false},
+    {"", false},
+    {"abcd", false},
+    // Trailing data:
+    {"6d247a34-53d5-40ec-a90d-d8dea9e94cc01", false}
+  };
+
+  const std::string empty_uuid = UUID().ToString();
+
+  for (size_t index = 0; index < arraysize(kCases); ++index) {
+    const TestCase& test_case = kCases[index];
+    SCOPED_TRACE(
+        base::StringPrintf("index %zu: %s", index, test_case.uuid_string));
+
+    UUID uuid;
+    EXPECT_EQ(test_case.success,
+              uuid.InitializeFromString(test_case.uuid_string));
+    if (test_case.success) {
+      EXPECT_EQ(test_case.uuid_string, uuid.ToString());
+    } else {
+      EXPECT_EQ(empty_uuid, uuid.ToString());
+    }
+  }
+
+  // Test for case insensitivty.
+  UUID uuid;
+  uuid.InitializeFromString("F32E5BDC-2681-4C73-A4E6-911FFD89B846");
+  EXPECT_EQ("f32e5bdc-2681-4c73-a4e6-911ffd89b846", uuid.ToString());
+
+  // Mixed case.
+  uuid.InitializeFromString("5762C15D-50b5-4171-a2e9-7429C9EC6CAB");
+  EXPECT_EQ("5762c15d-50b5-4171-a2e9-7429c9ec6cab", uuid.ToString());
+}
+
 }  // namespace
 }  // namespace test
 }  // namespace crashpad