ptr_copy = get_copy(obj)            # Get pointer copy
if is_unlocked(ptr_copy):           # Is obj free?
    return obj                      # return current obj
if is_copy(ptr_copy):               # Already a copy?
    return obj                      # return obj
thread_id = get_thread_id(ptr_copy)
if thread_id == ctx.thread_id:      # Locked by current ctx
    return ptr_copy                 # Return copy

// Add a horizontal scroll bar
hScrollBar = new JScrollBar(JScrollBar.HORIZONTAL);
add(hScrollBar, BorderLayout.SOUTH);
// Add a vertical scroll bar
vScrollBar = new JScrollBar(JScrollBar.VERTICAL);
add(vScrollBar, BorderLayout.EAST);
// Initialize the caret-position related values
caretX     = 0;
caretY     = 0;
caretMemX  = null;

/*
 * Obtain a normalized resource name from REQ.
 */
private static String[] getNormalizedResourceNames(
            HTTPRequest req) ...
/*
 * Downcast PARAMETER to TYPE.
 */
private static Object downCastParameter(String parameter, String type) ...
/*
 * The horizontal padding of each line in the text.
 */
private static final int textHorizontalPadding = 4;

/*
 * The amount of blank space to leave on the left and
 * right sides of each line of text, in pixels.
 */
private static final int textHorizontalPadding = 4;

// Current offset in resp Buffer
uint32_t offset;
// Contains all line-widths inside the document and
// number of appearances.
private TreeMap<Integer, Integer> lineWidths;

//  Position in this buffer of the first object that hasn't
//  been returned to the client.
uint32_t offset;
//  Holds statistics about line lengths of the form <length, count>
//  where length is the number of characters in a line (including
//  the newline), and count is the number of lines with
//  exactly that many characters. If there are no lines with
//  a particular length, then there is no entry for that length.
private TreeMap<Integer, Integer> numLinesWithLength;

/* FOLLOWER VARIABLE: indicator variable that allows the Receiver and the
 * PeriodicTasks thread to communicate about whether a heartbeat has been
 * received within the follower's election timeout window.
 * Toggled to TRUE when a valid heartbeat is received.
 * Toggled to FALSE when the election timeout window is reset.  */
private boolean receivedValidHeartbeat;

// If there is a LOADING readRpc using the same session
// as PKHash pointed to by assignPos, and the last PKHash
// in that readRPC is smaller than current assigning
// PKHash, then we put assigning PKHash into that readRPC.
int readActiveRpcId = RPC_ID_NOT_ASSIGNED;
for (int i = 0; i < NUM_READ_RPC; i++) {
    if (session == readRpc[i].session
            && readRpc[i].status == LOADING
            && readRpc[i].maxPos < assignPos
            && readRpc[i].numHashes < MAX_PKHASHES_PERRPC) {
        readActiveRpcId = i;
        break;
    }
}

// Try to append the current key hash onto an existing
// RPC to the desired server that hasn't been sent yet.

if (numProcessedPKHashes < readRpc[i].numHashes) {
    // Some of the key hashes couldn't be looked up in
    // this request (either because they aren't stored
    // on the server, the server crashed, or there
    // wasn't enough space in the response message).
    // Mark the unprocessed hashes so they will get
    // reassigned to new RPCs.
    for (size_t p = removePos; p < insertPos; p++) {
        if (activeRpcId[p] == i) {
            if (numProcessedPKHashes > 0) {
                numProcessedPKHashes--;
            } else {
                if (p < assignPos)
                    assignPos = p;
                activeRpcId[p] = RPC_ID_NOT_ASSIGNED;
            }
        }
    }
}

/**
 * This class implements a simple server-side interface to the HTTP
 * protocol: by using this class, an application can receive HTTP
 * requests, process them, and return responses. Each instance of
 * this class corresponds to a particular socket used to receive
 * requests. The current implementation is single-threaded and
 * processes one request at a time.
 */
public class Http {...}

/**
 * Copy a range of bytes from a buffer to an external location.
 *
 * \param offset
 *        Index within the buffer of the first byte to copy.
 * \param length
 *        Number of bytes to copy.
 * \param dest
 *        Where to copy the bytes: must have room for at least
 *        length bytes.
 *
 * \return
 *        The return value is the actual number of bytes copied,
 *        which may be less than length if the requested range of
 *        bytes extends past the end of the buffer. 0 is returned
 *        if there is no overlap between the requested range and
 *        the actual buffer.
 */
uint32_t
Buffer::copy(uint32_t offset, uint32_t length, void* dest)
...

query = new IndexLookup(table, index, key1, key2);
while  (true) {
    object = query.getNext();
    if  (object == NULL) {
        break;
    }
    ... process object ...
}

/*
 * This class implements the client side framework for index range
 * lookups. It manages a single LookupIndexKeys RPC and multiple
 * IndexedRead RPCs. Client side just includes "IndexLookup.h" in
 * its header to use IndexLookup class. Several parameters can be set
 * in the config below:
 * - The number of concurrent indexedRead RPCs
 * - The max number of PKHashes a indexedRead RPC can hold at a time
 * - The size of the active PKHashes
 *
 * To use IndexLookup, the client creates an object of this class by
 * providing all necessary information. After construction of
 * IndexLookup, client can call getNext() function to move to next
 * available object. If getNext() returns NULL, it means we reached
 * the last object. Client can use getKey, getKeyLength, getValue,
 * and getValueLength to get object data of current object.
 */
 class IndexLookup {
       ...
   private:
       /// Max number of concurrent indexedRead RPCs
       static const uint8_t NUM_READ_RPC = 10;
       /// Max number of PKHashes that can be sent in one
       /// indexedRead RPC
       static const uint32_t MAX_PKHASHES_PERRPC = 256;
       /// Max number of PKHashes that activeHashes can
       /// hold at once.
       static const size_t MAX_NUM_PK = (1 << LG_BUFFER_SIZE);
 }

/*
 * This class is used by client applications to make range queries
 * using indexes. Each instance represents a single range query.
 *
 * To start a range query, a client creates an instance of this
 * class. The client can then call getNext() to retrieve the objects
 * in the desired range. For each object returned by getNext(), the
 * caller can invoke getKey(), getKeyLength(), getValue(), and
 * getValueLength() to get information about that object.
 */

/**
 * Check if the next object is RESULT_READY. This function is
 * implemented in a DCFT module, each execution of isReady() tries
 * to make small progress, and getNext() invokes isReady() in a
 * while loop, until isReady() returns true.
 *
 * isReady() is implemented in a rule-based approach. We check
 * different rules by following a particular order, and perform
 * certain actions if some rule is satisfied.
 *
 * \return
 *         True means the next Object is available. Otherwise, return
 *         false.
 */
bool IndexLookup::isReady() { ... }

/*
 * Indicates whether an indexed read has made enough progress for
 * getNext to return immediately without blocking. In addition, this
 * method does most of the real work for indexed reads, so it must
 * be invoked (either directly, or indirectly by calling getNext) in
 * order for the indexed read to make progress.
 *
 * \return
 *         True means that the next invocation of getNext will not block
 *         (at least one object is available to return, or the end of the
 *         lookup has been reached); false means getNext may block.
 */

// Phase 1: Scan active RPCs to see if any have completed.

// Each iteration of the following loop extracts one request from
// the request message, increments the corresponding object, and
// appends a response to the response message.

typedef enum Status {
    STATUS_OK = 0,
    STATUS_UNKNOWN_TABLET                = 1,
    STATUS_WRONG_VERSION                 = 2,
    ...
    STATUS_INDEX_DOESNT_EXIST            = 29,
    STATUS_INVALID_PARAMETER             = 30,
    STATUS_MAX_VALUE                     = 30,
    // Note: if you add a new status value you must make the following
    // additional updates:
    // (1)  Modify STATUS_MAX_VALUE to have a value equal to the
    //      largest defined status value, and make sure its definition
    //      is the last one in the list. STATUS_MAX_VALUE is used
    //      primarily for testing.
    // (2)  Add new entries in the tables "messages" and "symbols" in
    //      Status.cc.
    // (3)  Add a new exception class to ClientException.h
    // (4)  Add a new "case" to ClientException::throwException to map
    //      from the status value to a status-specific ClientException
    //      subclass.
    // (5)  In the Java bindings, add a static class for the exception
    //      to ClientException.java
    // (6)  Add a case for the status of the exception to throw the
    //      exception in ClientException.java
    // (7)  Add the exception to the Status enum in Status.java, making
    //      sure the status is in the correct position corresponding to
    //      its status code.
}

...
Zombies
-------
A zombie is a server that is considered dead by the rest of the
cluster; any data stored on the server has been recovered and will
be managed by other servers. However, if a zombie is not actually
dead (e.g., it was just disconnected from the other servers for a
while) two forms of inconsistency can arise:
* A zombie server must not serve read requests once replacement servers have taken over; otherwise it may return stale data that does not reflect writes accepted by the replacement servers.
* The zombie server must not accept write requests once replacement servers have begun replaying its log during recovery; if it does, these writes may be lost (the new values may not be stored on the replacement servers and thus will not be returned by reads).
RAMCloud uses two techniques to neutralize zombies. First,
...

// See "Zombies" in designNotes.