Bring across the JDWP implementation.

This compiles and links, but does nothing until we fill out the 100 or so
unimplemented methods in "debugger.cc". Note that I also need to add the
extra command-line handling for the JDWP agent stuff, and add calls from
the runtime to the various "something interesting is going on" hooks.

Change-Id: I477cf3caf9e248c384ce1d739cbfadb60e2008bc
diff --git a/src/jdwp/jdwp_expand_buf.cc b/src/jdwp/jdwp_expand_buf.cc
new file mode 100644
index 0000000..f1675fd
--- /dev/null
+++ b/src/jdwp/jdwp_expand_buf.cc
@@ -0,0 +1,174 @@
+/*
+ * Copyright (C) 2008 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.
+ */
+/*
+ * Implementation of an expandable byte buffer.  Designed for serializing
+ * primitive values, e.g. JDWP replies.
+ */
+
+#include "jdwp/jdwp_bits.h"
+#include "jdwp/jdwp_expand_buf.h"
+#include "logging.h"
+
+#include <stdlib.h>
+#include <string.h>
+
+namespace art {
+
+namespace JDWP {
+
+/*
+ * Data structure used to track buffer use.
+ */
+struct ExpandBuf {
+  uint8_t*     storage;
+  int     curLen;
+  int     maxLen;
+};
+
+#define kInitialStorage 64
+
+/*
+ * Allocate a JdwpBuf and some initial storage.
+ */
+ExpandBuf* expandBufAlloc() {
+  ExpandBuf* newBuf;
+
+  newBuf = (ExpandBuf*) malloc(sizeof(*newBuf));
+  newBuf->storage = (uint8_t*) malloc(kInitialStorage);
+  newBuf->curLen = 0;
+  newBuf->maxLen = kInitialStorage;
+
+  return newBuf;
+}
+
+/*
+ * Free a JdwpBuf and associated storage.
+ */
+void expandBufFree(ExpandBuf* pBuf) {
+  if (pBuf == NULL) {
+    return;
+  }
+
+  free(pBuf->storage);
+  free(pBuf);
+}
+
+/*
+ * Get a pointer to the start of the buffer.
+ */
+uint8_t* expandBufGetBuffer(ExpandBuf* pBuf) {
+  return pBuf->storage;
+}
+
+/*
+ * Get the amount of data currently in the buffer.
+ */
+size_t expandBufGetLength(ExpandBuf* pBuf) {
+  return pBuf->curLen;
+}
+
+
+/*
+ * Ensure that the buffer has enough space to hold incoming data.  If it
+ * doesn't, resize the buffer.
+ */
+static void ensureSpace(ExpandBuf* pBuf, int newCount) {
+  if (pBuf->curLen + newCount <= pBuf->maxLen) {
+    return;
+  }
+
+  while (pBuf->curLen + newCount > pBuf->maxLen) {
+    pBuf->maxLen *= 2;
+  }
+
+  uint8_t* newPtr = (uint8_t*) realloc(pBuf->storage, pBuf->maxLen);
+  if (newPtr == NULL) {
+    LOG(ERROR) << "realloc(" << pBuf->maxLen << ") failed";
+    abort();
+  }
+
+  pBuf->storage = newPtr;
+}
+
+/*
+ * Allocate some space in the buffer.
+ */
+uint8_t* expandBufAddSpace(ExpandBuf* pBuf, int gapSize) {
+  uint8_t* gapStart;
+
+  ensureSpace(pBuf, gapSize);
+  gapStart = pBuf->storage + pBuf->curLen;
+  /* do we want to garbage-fill the gap for debugging? */
+  pBuf->curLen += gapSize;
+
+  return gapStart;
+}
+
+/*
+ * Append a byte.
+ */
+void expandBufAdd1(ExpandBuf* pBuf, uint8_t val) {
+  ensureSpace(pBuf, sizeof(val));
+  *(pBuf->storage + pBuf->curLen) = val;
+  pBuf->curLen++;
+}
+
+/*
+ * Append two big-endian bytes.
+ */
+void expandBufAdd2BE(ExpandBuf* pBuf, uint16_t val) {
+  ensureSpace(pBuf, sizeof(val));
+  set2BE(pBuf->storage + pBuf->curLen, val);
+  pBuf->curLen += sizeof(val);
+}
+
+/*
+ * Append four big-endian bytes.
+ */
+void expandBufAdd4BE(ExpandBuf* pBuf, uint32_t val) {
+  ensureSpace(pBuf, sizeof(val));
+  set4BE(pBuf->storage + pBuf->curLen, val);
+  pBuf->curLen += sizeof(val);
+}
+
+/*
+ * Append eight big-endian bytes.
+ */
+void expandBufAdd8BE(ExpandBuf* pBuf, uint64_t val) {
+  ensureSpace(pBuf, sizeof(val));
+  set8BE(pBuf->storage + pBuf->curLen, val);
+  pBuf->curLen += sizeof(val);
+}
+
+/*
+ * Add a UTF8 string as a 4-byte length followed by a non-NULL-terminated
+ * string.
+ *
+ * Because these strings are coming out of the VM, it's safe to assume that
+ * they can be null-terminated (either they don't have null bytes or they
+ * have stored null bytes in a multi-byte encoding).
+ */
+void expandBufAddUtf8String(ExpandBuf* pBuf, const uint8_t* str) {
+  int strLen = strlen((const char*)str);
+
+  ensureSpace(pBuf, sizeof(uint32_t) + strLen);
+  setUtf8String(pBuf->storage + pBuf->curLen, str);
+  pBuf->curLen += sizeof(uint32_t) + strLen;
+}
+
+}  // namespace JDWP
+
+}  // namespace art