Test readx/writex (now renamed).

Renamed readx/writex to ReadFdExactly/WriteFdExactly respectively.
These read/write a full fixed-size buffer. If the whole buffer cannot
be read/written, these functions return an error.

Rename write_string to WriteStringFully.

Move the TEMP_FAILURE_RETRY definition in sysdeps.h out of the
!Windows section. It seems Windows won't actually interrupt a call,
but it's easier to just define it than to #ifdef each call.

Change-Id: Ia8ddffa2a52764a2f9a281c96c937660e002b9b9
diff --git a/adb/adb_io_test.cpp b/adb/adb_io_test.cpp
new file mode 100644
index 0000000..330d9ce
--- /dev/null
+++ b/adb/adb_io_test.cpp
@@ -0,0 +1,142 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "adb_io.h"
+
+#include <gtest/gtest.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include <string>
+
+#include "utils/file.h"
+
+class TemporaryFile {
+ public:
+  TemporaryFile() {
+    init("/data/local/tmp");
+    if (fd == -1) {
+      init("/tmp");
+    }
+  }
+
+  ~TemporaryFile() {
+    close(fd);
+    unlink(filename);
+  }
+
+  int fd;
+  char filename[1024];
+
+ private:
+  void init(const char* tmp_dir) {
+    snprintf(filename, sizeof(filename), "%s/TemporaryFile-XXXXXX", tmp_dir);
+    fd = mkstemp(filename);
+  }
+};
+
+TEST(io, ReadFdExactly_whole) {
+  const char expected[] = "Foobar";
+  TemporaryFile tf;
+  ASSERT_NE(-1, tf.fd);
+
+  ASSERT_TRUE(android::WriteStringToFd(expected, tf.fd)) << strerror(errno);
+  ASSERT_EQ(0, lseek(tf.fd, SEEK_SET, 0));
+
+  // Test reading the whole file.
+  char buf[sizeof(expected)] = {};
+  ASSERT_TRUE(ReadFdExactly(tf.fd, buf, sizeof(buf) - 1)) << strerror(errno);
+  EXPECT_STREQ(expected, buf);
+}
+
+TEST(io, ReadFdExactly_eof) {
+  const char expected[] = "Foobar";
+  TemporaryFile tf;
+  ASSERT_NE(-1, tf.fd);
+
+  ASSERT_TRUE(android::WriteStringToFd(expected, tf.fd)) << strerror(errno);
+  ASSERT_EQ(0, lseek(tf.fd, SEEK_SET, 0));
+
+  // Test that not having enough data will fail.
+  char buf[sizeof(expected) + 1] = {};
+  ASSERT_FALSE(ReadFdExactly(tf.fd, buf, sizeof(buf)));
+  EXPECT_EQ(0, errno) << strerror(errno);
+}
+
+TEST(io, ReadFdExactly_partial) {
+  const char input[] = "Foobar";
+  TemporaryFile tf;
+  ASSERT_NE(-1, tf.fd);
+
+  ASSERT_TRUE(android::WriteStringToFd(input, tf.fd)) << strerror(errno);
+  ASSERT_EQ(0, lseek(tf.fd, SEEK_SET, 0));
+
+  // Test reading a partial file.
+  char buf[sizeof(input) - 1] = {};
+  ASSERT_TRUE(ReadFdExactly(tf.fd, buf, sizeof(buf) - 1));
+
+  std::string expected(input);
+  expected.pop_back();
+  EXPECT_STREQ(expected.c_str(), buf);
+}
+
+TEST(io, WriteFdExactly_whole) {
+  const char expected[] = "Foobar";
+  TemporaryFile tf;
+  ASSERT_NE(-1, tf.fd);
+
+  // Test writing the whole string to the file.
+  ASSERT_TRUE(WriteFdExactly(tf.fd, expected, sizeof(expected)))
+    << strerror(errno);
+  ASSERT_EQ(0, lseek(tf.fd, SEEK_SET, 0));
+
+  std::string s;
+  ASSERT_TRUE(android::ReadFdToString(tf.fd, &s));
+  EXPECT_STREQ(expected, s.c_str());
+}
+
+TEST(io, WriteFdExactly_partial) {
+  const char buf[] = "Foobar";
+  TemporaryFile tf;
+  ASSERT_NE(-1, tf.fd);
+
+  // Test writing a partial string to the file.
+  ASSERT_TRUE(WriteFdExactly(tf.fd, buf, sizeof(buf) - 2)) << strerror(errno);
+  ASSERT_EQ(0, lseek(tf.fd, SEEK_SET, 0));
+
+  std::string expected(buf);
+  expected.pop_back();
+
+  std::string s;
+  ASSERT_TRUE(android::ReadFdToString(tf.fd, &s));
+  EXPECT_EQ(expected, s);
+}
+
+TEST(io, WriteStringFully) {
+  const char str[] = "Foobar";
+  TemporaryFile tf;
+  ASSERT_NE(-1, tf.fd);
+
+  // Test writing a partial string to the file.
+  ASSERT_TRUE(WriteStringFully(tf.fd, str)) << strerror(errno);
+  ASSERT_EQ(0, lseek(tf.fd, SEEK_SET, 0));
+
+  std::string s;
+  ASSERT_TRUE(android::ReadFdToString(tf.fd, &s));
+  EXPECT_STREQ(str, s.c_str());
+}