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<h1>Target Communication Framework Services - Stack Trace</h1>

<ul>
    <li><a href='#VersionHistory'>Version History</a>
    <li><a href='#Overview'>Overview</a>
    <li><a href='#Cmds'>Commands</a>
    <ul>
        <li><a href='#CmdGetContext'>Get Context</a>
        <li><a href='#CmdGetChildren'>Get Children</a>
        <li><a href='#CmdGetChildrenRange'>Get Children Range</a></ul>
    <li><a href='#Events'>Events</a>
    <li><a href='#API'>API</a>
</ul>

<h1>Stack Trace Service</h1>

<h2><a name='VersionHistory'>Version History</a></h2>

<table border=1 cellpadding=8>
    <tr>
        <th>Version
        <th>Date
        <th>Change
    <tr>
        <td>0.1
        <td>2008-01-10
        <td>Initial contribution
    <tr>
        <td>1.2
        <td>2013-07-12
        <td>New command: getChildrenRange.
        Stack frame property "Level" is replaced with "Index".
    <tr>
        <td>1.3
        <td>2015-05-20
        <td>Fixed description of getChildrenRange.
        New properties: CodeArea and FuncID.
</table>

<h2><a name='Overview'>Overview</a></h2>

<p>The service implements thread stack back tracing. Command
and event parameters are encoded as zero terminated <a href='TCF Specification.html#JSON'>JSON</a> strings.</p>

<p>The service uses standard format for error reports,
see <a href='TCF Services.html#ErrorFormat'>Error Report Format</a>.</p>

<h2><a name='Cmds'>Commands</a></h2>

<h3><a name='CmdGetContext'>Get Context</a></h3>

<pre><b><font face="Courier New" size=2 color=#333399>
C &bull; <i>&lt;token&gt;</i> &bull; StackTrace &bull; getContext &bull; <i>&lt;array of context IDs&gt;</i> &bull;

<i>&lt;array of context IDs&gt;</i>
    &rArr; null
    &rArr; [ ]
    &rArr; [ <i>&lt;context ID list&gt;</i> ]

<i>&lt;context ID list&gt;</i>
    &rArr; <i>&lt;string: context ID&gt;</i>
    &rArr; <i>&lt;context ID list&gt;</i> , <i>&lt;string: context ID&gt;</i>
</font></b></pre>

<p>The command retrieves context info for given context IDs.
Command allows to query multiple contexts at once.
Stack Trace context represents single stack frame.
If target supports more then one stack per thread,
each stack is also represented by a separate context.</p>

<p>Reply:</p>

<pre><b><font face="Courier New" size=2 color=#333399>
R &bull; <i>&lt;token&gt;</i> &bull; <i>&lt;array of context data&gt;</i> &bull; <i>&lt;error report&gt;</i> &bull;

<i>&lt;array of context data&gt;</i>
    &rArr; null
    &rArr; [ ]
    &rArr; [ <i>&lt;context data list&gt;</i> ]

<i>&lt;context data list&gt;</i>
    &rArr; <i>&lt;context data&gt;</i>
    &rArr; <i>&lt;context data list&gt;</i> , <i>&lt;context data&gt;</i>

<i>&lt;context data&gt;</i>
    &rArr; null
    &rArr; <i>&lt;object&gt;</i>
</font></b></pre>

<p>Context data object should, at least, contain member
<b><font face="Courier New" size=2 color=#333399>"ID" : <i>&lt;string&gt;.</i></font></b>
Context data is expected to be cached by clients.
Cached context data should by flushed when parent thread is resumed.</p>

<p>Predefined stack trace context properties are:</p>
<ul>
    <li><code><b><font face="Courier New" size=2 color=#333399>"ID" : <i>&lt;string&gt;</i></font></b></code>
    - ID of the context, same as getContext command argument.

    <li><code><b><font face="Courier New" size=2 color=#333399>"ParentID" : <i>&lt;string&gt;</i></font></b></code>
    - ID of a parent context.

    <li><code><b><font face="Courier New" size=2 color=#333399>"ProcessID" : <i>&lt;string&gt;</i></font></b></code>
    - process ID.

    <li><code><b><font face="Courier New" size=2 color=#333399>"Name" : <i>&lt;string&gt;</i></font></b></code>
    - context name if context is a stack.

    <li><code><b><font face="Courier New" size=2 color=#333399>"TopFrame" : <i>&lt;boolean&gt;</i></font></b></code>
    - true if the frame is top frame on a stack.

    <li><code><b><font face="Courier New" size=2 color=#333399>"Index" : <i>&lt;number&gt;</i></font></b></code>
    - frame index. Topmost (current) frame has index 0.

    <li><code><b><font face="Courier New" size=2 color=#333399>"Walk" : <i>&lt;boolean&gt;</i></font></b></code>
    - true if the frame data was computed using symbols info,
    false or not set if the data was collected using stack crawl logic.

    <li><code><b><font face="Courier New" size=2 color=#333399>"FP" : <i>&lt;number&gt;</i></font></b></code>
    - frame pointer - memory address of stack frame.

    <li><code><b><font face="Courier New" size=2 color=#333399>"RP" : <i>&lt;number&gt;</i></font></b></code>
    - return pointer - return address.

    <li><code><b><font face="Courier New" size=2 color=#333399>"IP" : <i>&lt;number&gt;</i></font></b></code>
    - instruction pointer - memory address of current instruction.

    <li><code><b><font face="Courier New" size=2 color=#333399>"ArgsCnt" : <i>&lt;number&gt;</i></font></b></code>
    - function arguments count

    <li><code><b><font face="Courier New" size=2 color=#333399>"ArgsAddr" : <i>&lt;number&gt;</i></font></b></code>
    - memory address of function arguments

    <li><code><b><font face="Courier New" size=2 color=#333399>"CodeArea" : <i>&lt;number&gt;</i></font></b></code>
    - source code location of the frame

    <li><code><b><font face="Courier New" size=2 color=#333399>"FuncID" : <i>&lt;number&gt;</i></font></b></code>
    - function symbol ID.
</ul>

<h3><a name='CmdGetChildren'>Get Children</a></h3>

<pre><b><font face="Courier New" size=2 color=#333399>
C &bull; <i>&lt;token&gt;</i> &bull; StackTrace &bull; getChildren &bull; <i>&lt;string: parent context ID&gt;</i> &bull;
</font></b></pre>

<p>The command retrieves stack trace context ID list.
Parent context usually corresponds to an execution thread.
Some targets have more then one stack. In such case children of a thread
are stacks, and stack frames are deeper in the hierarchy - they can be
retrieved with additional getChildren commands.</p>

<p>The command will fail if parent thread is not suspended.
Client can use Run Control service to suspend a thread.</p>

<p>Reply:</p>

<pre><b><font face="Courier New" size=2 color=#333399>
R &bull; <i>&lt;token&gt;</i> &bull; <i>&lt;error report&gt;</i> &bull; <i>&lt;array of context IDs&gt;</i> &bull;<i></i>

<i>&lt;array of context IDs&gt;</i>
    &rArr; null
    &rArr; [ ]
    &rArr; [ <i>&lt;context ID list&gt;</i> ]

<i>&lt;context ID list&gt;</i>
    &rArr; <i>&lt;string: context ID&gt;</i>
    &rArr; <i>&lt;context ID list&gt;</i> , <i>&lt;string: context ID&gt;</i>

</font></b></pre>

<h3><a name='CmdGetChildrenRange'>Get Children Range</a></h3>

<pre><b><font face="Courier New" size=2 color=#333399>
C &bull; <i>&lt;token&gt;</i> &bull; StackTrace &bull; getChildrenRange &bull; <i>&lt;string: parent context ID&gt;</i> &bull; <i>&lt;int: range start&gt;</i> &bull; <i>&lt;int: range end&gt;</i> &bull;
</font></b></pre>

<p>The command retrieves a range of stack trace context IDs.
Parent context usually corresponds to an execution thread.</p>
<p>Note: to allow partial and incremental stack tracing, IDs ordering in
the range is reversed relative to getChildren command order.
For example, range 0..1 represents last two stack frames:
current frame (top of the stack) and previous one.</p>
<p>The command will fail if parent thread is not suspended.
Client can use Run Control service to suspend a thread.</p>

<p>Reply: same as Get Children reply.</p>

<h2><a name='Events'>Events</a></h2>

<p>No events are currently defined for Stack Trace service.</p>

<h2><a name='API'>API</a></h2>

<pre>
<font color=#7F0055>public interface</font> IStackTrace <font color=#7F0055>extends</font> IService {

    <font color=#7F0055>static final</font> String NAME = "StackTrace";

    <font color=#3F5FBF>/**
     * Context property names.
     */</font>
    <font color=#7F0055>static final</font> String
        PROP_ID = "ID",                         <font color=#3F5FBF>/** String, stack frame ID */</font>
        PROP_PARENT_ID = "ParentID",            <font color=#3F5FBF>/** String, stack frame parent ID */</font>
        PROP_PROCESS_ID = "ProcessID",          <font color=#3F5FBF>/** String, stack frame process ID */</font>
        PROP_NAME = "Name",                     <font color=#3F5FBF>/** String, human readable name */</font>
        PROP_TOP_FRAME = "TopFrame",            <font color=#3F5FBF>/** Boolean, true if the frame is top frame on a stack */</font>
        PROP_INDEX = "Index",                   <font color=#3F5FBF>/** Integer, stack frame index, starting from stack top (current frame) */</font>
        PROP_WALK = "Walk",                     <font color=#3F5FBF>/** Boolean, true if the frame data was computed using symbols info */</font>
        PROP_FRAME_ADDRESS = "FP",              <font color=#3F5FBF>/** Number, stack frame memory address */</font>
        PROP_RETURN_ADDRESS = "RP",             <font color=#3F5FBF>/** Number, return address */</font>
        PROP_INSTRUCTION_ADDRESS = "IP",        <font color=#3F5FBF>/** Number, instruction pointer */</font>
        PROP_ARGUMENTS_COUNT = "ArgsCnt",       <font color=#3F5FBF>/** Integer, number of function arguments */</font>
        PROP_ARGUMENTS_ADDRESS = "ArgsAddr",    <font color=#3F5FBF>/** Number, memory address of function arguments */</font>
        PROP_CODE_AREA = "CodeArea",            <font color=#3F5FBF>/** ILineNumbers.CodeArea, source code location of the frame */</font>
        PROP_FUNC_ID = "FuncID";                <font color=#3F5FBF>/** String, function symbol ID */</font>

    <font color=#3F5FBF>/**
     * Retrieve context info for given context IDs.
     *
     * The command will fail if parent thread is not suspended.
     * Client can use Run Control service to suspend a thread.
     *
     * <font color=#7F9FBF>@param</font> id &ndash; array of context IDs.
     * <font color=#7F9FBF>@param</font> done - call back interface called when operation is completed.
     */</font>
    IToken getContext(String[] id, DoneGetContext done);

    <font color=#3F5FBF>/**
     * Client call back interface for getContext().
     */</font>
    <font color=#7F0055>interface</font> DoneGetContext {
        <font color=#3F5FBF>/**
         * Called when context data retrieval is done.
         * <font color=#7F9FBF>@param</font> error &ndash; error description if operation failed, null if succeeded.
         * <font color=#7F9FBF>@param</font> context &ndash; array of context data or null if error.
         */</font>
        <font color=#7F0055>void</font> doneGetContext(IToken token, Exception error, StackTraceContext[] context);
    }

    <font color=#3F5FBF>/**
     * Retrieve stack trace context ID list.
     * Parent context usually corresponds to an execution thread.
     * Some targets have more then one stack. In such case children of a thread
     * are stacks, and stack frames are deeper in the hierarchy - they can be
     * retrieved with additional getChildren commands.
     *
     * Stack frames are ordered from stack bottom to top.
     *
     * The command will fail if parent thread is not suspended.
     * Client can use Run Control service to suspend a thread.
     *
     * <font color=#7F9FBF>@param</font> parent_context_id &ndash; parent context ID.
     * <font color=#7F9FBF>@param</font> done - call back interface called when operation is completed.
     */</font>
    IToken getChildren(String parent_context_id, DoneGetChildren done);

    <font color=#3F5FBF>/**
     * Retrieve a range of stack trace context IDs.
     * Parent context usually corresponds to an execution thread.
     *
     * Note: to allow partial and incremental stack tracing, IDs ordering in
     * the range is reversed relative to getChildren command order.
     * For example, range 0..1 represents last two stack frames:
     * current frame (top of the stack) and previous one.
     *
     * The command will fail if parent thread is not suspended.
     * Client can use Run Control service to suspend a thread.
     *
     * <font color=#7F9FBF>@param</font> parent_context_id - parent context ID.
     * <font color=#7F9FBF>@param</font> range_start - start of the range (inclusive).
     * <font color=#7F9FBF>@param</font> range_end - end of the range (inclusive).
     * <font color=#7F9FBF>@param</font> done - call back interface called when operation is completed.
     * <font color=#7F9FBF>@since 1.2</font>
     */</font>
    IToken getChildrenRange(String parent_context_id, int range_start, int range_end, DoneGetChildren done);

    <font color=#3F5FBF>/**
     * Client call back interface for getChildren() and getChildrenRange().
     */</font>
    <font color=#7F0055>interface</font> DoneGetChildren {
        <font color=#3F5FBF>/**
         * Called when context ID list retrieval is done.
         * <font color=#7F9FBF>@param</font> error &ndash; error description if operation failed, null if succeeded.
         * <font color=#7F9FBF>@param</font> context_ids &ndash; array of available context IDs.
         */</font>
        <font color=#7F0055>void</font> doneGetChildren(IToken token, Exception error, String[] context_ids);
    }

    <font color=#3F5FBF>/**
     * StackTraceContext represents stack trace objects - stacks and stack frames.
     */</font>
    <font color=#7F0055>interface</font> StackTraceContext {

        <font color=#3F5FBF>/**
         * Get Context ID.
         * <font color=#7F9FBF>@return</font> context ID.
         */</font>
        String getID();

        <font color=#3F5FBF>/**
         * Get parent context ID.
         * <font color=#7F9FBF>@return</font> parent context ID.
         */</font>
        String getParentID();

        <font color=#3F5FBF>/**
         * Get context name - if context represents a stack.
         * <font color=#7F9FBF>@return</font> context name or null.
         */</font>
        String getName();

        <font color=#3F5FBF>/**
         * Get memory address of this frame.
         * <font color=#7F9FBF>@return</font> address or null if not a stack frame.
         */</font>
        Number getFrameAddress();

        <font color=#3F5FBF>/**
         * Get program counter saved in this stack frame -
         * it is address of instruction to be executed when the function returns.
         * <font color=#7F9FBF>@return</font> return address or null if not a stack frame.
         */</font>
        Number getReturnAddress();

        <font color=#3F5FBF>/**
         * Get address of the next instruction to be executed in this stack frame.
         * For top frame it is same as PC register value.
         * For other frames it is same as return address of the next frame.
         * <font color=#7F9FBF>@return</font> instruction address or null if not a stack frame.
         */</font>
        Number getInstructionAddress();

        <font color=#3F5FBF>/**
         * Get number of function arguments for this frame.
         * <font color=#7F9FBF>@return</font> function arguments count.
         */</font>
        <font color=#7F0055>int</font> getArgumentsCount();

        <font color=#3F5FBF>/**
         * Get address of function arguments area in memory.
         * <font color=#7F9FBF>@return</font> function arguments address or null if not available.
         */</font>
        Number getArgumentsAddress();

        <font color=#3F5FBF>/**
         * Get code area that describes source code location of the frame.
         * If null, client should use LineNumbers service to find frame source location.
         * <font color=#7F9FBF>@return</font> code area or null.
         * <font color=#7F9FBF>@since 1.3</font>
         */</font>
        ILineNumbers.CodeArea getCodeArea();

        <font color=#3F5FBF>/**
         * Get function symbol ID.
         * If null, client should use Symbols service to find function symbol ID.
         * <font color=#7F9FBF>@return</font> function symbol ID or null.
         * <font color=#7F9FBF>@since 1.3</font>
         */</font>
        String getFuncID();

        <font color=#3F5FBF>/**
         * Get complete map of context properties.
         * <font color=#7F9FBF>@return</font> map of context properties.
         */</font>
        Map&lt;String,Object&gt; getProperties();
    }
}
</pre>

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