SBValue.h

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//===-- SBValue.h -----------------------------------------------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

#ifndef LLDB_SBValue_h_
#define LLDB_SBValue_h_

#include "lldb/API/SBData.h"
#include "lldb/API/SBDefines.h"
#include "lldb/API/SBType.h"

class ValueImpl;
class ValueLocker;

namespace lldb {

class SBValue
{
friend class ValueLocker;

public:
    SBValue ();

    SBValue (const lldb::SBValue &rhs);

    lldb::SBValue &
    operator =(const lldb::SBValue &rhs);
    
    ~SBValue ();

    bool
    IsValid();
    
    void
    Clear();
    
    SBError
    GetError();

    lldb::user_id_t
    GetID ();
    
    const char *
    GetName();

    const char *
    GetTypeName ();

    size_t
    GetByteSize ();

    bool
    IsInScope ();

    lldb::Format
    GetFormat ();
    
    void
    SetFormat (lldb::Format format);

    const char *
    GetValue ();

    int64_t
    GetValueAsSigned (lldb::SBError& error, int64_t fail_value=0);
    
    uint64_t
    GetValueAsUnsigned (lldb::SBError& error, uint64_t fail_value=0);
    
    int64_t
    GetValueAsSigned(int64_t fail_value=0);
    
    uint64_t
    GetValueAsUnsigned(uint64_t fail_value=0);

    ValueType
    GetValueType ();

    bool
    GetValueDidChange ();

    const char *
    GetSummary ();
    
    const char *
    GetObjectDescription ();
    
    lldb::SBValue
    GetDynamicValue (lldb::DynamicValueType use_dynamic);
    
    lldb::SBValue
    GetStaticValue ();
    
    lldb::SBValue
    GetNonSyntheticValue ();
    
    lldb::DynamicValueType
    GetPreferDynamicValue ();
    
    void
    SetPreferDynamicValue (lldb::DynamicValueType use_dynamic);
    
    bool
    GetPreferSyntheticValue ();
    
    void
    SetPreferSyntheticValue (bool use_synthetic);
    
    bool
    IsDynamic ();
    
    bool
    IsSynthetic ();

    const char *
    GetLocation ();

    // Deprecated - use the one that takes SBError&
    bool
    SetValueFromCString (const char *value_str);

    bool
    SetValueFromCString (const char *value_str, lldb::SBError& error);
    
    lldb::SBTypeFormat
    GetTypeFormat ();
    
#ifndef LLDB_DISABLE_PYTHON
    lldb::SBTypeSummary
    GetTypeSummary ();
#endif

    lldb::SBTypeFilter
    GetTypeFilter ();
    
#ifndef LLDB_DISABLE_PYTHON
    lldb::SBTypeSynthetic
    GetTypeSynthetic ();
#endif

    lldb::SBValue
    GetChildAtIndex (uint32_t idx);
    
    lldb::SBValue
    CreateChildAtOffset (const char *name, uint32_t offset, lldb::SBType type);
    
    lldb::SBValue
    Cast (lldb::SBType type);
    
    lldb::SBValue
    CreateValueFromExpression (const char *name, const char* expression);
    
    lldb::SBValue
    CreateValueFromExpression (const char *name, const char* expression, SBExpressionOptions &options);
    
    lldb::SBValue
    CreateValueFromAddress (const char* name, 
                            lldb::addr_t address, 
                            lldb::SBType type);
    
    // this has no address! GetAddress() and GetLoadAddress() as well as AddressOf()
    // on the return of this call all return invalid
    lldb::SBValue
    CreateValueFromData (const char* name,
                         lldb::SBData data,
                         lldb::SBType type);

    //------------------------------------------------------------------
    /// Get a child value by index from a value.
    ///
    /// Structs, unions, classes, arrays and and pointers have child
    /// values that can be access by index. 
    ///
    /// Structs and unions access child members using a zero based index
    /// for each child member. For
    /// 
    /// Classes reserve the first indexes for base classes that have 
    /// members (empty base classes are omitted), and all members of the
    /// current class will then follow the base classes. 
    ///
    /// Pointers differ depending on what they point to. If the pointer
    /// points to a simple type, the child at index zero
    /// is the only child value available, unless \a synthetic_allowed 
    /// is \b true, in which case the pointer will be used as an array
    /// and can create 'synthetic' child values using positive or 
    /// negative indexes. If the pointer points to an aggregate type 
    /// (an array, class, union, struct), then the pointee is 
    /// transparently skipped and any children are going to be the indexes
    /// of the child values within the aggregate type. For example if
    /// we have a 'Point' type and we have a SBValue that contains a
    /// pointer to a 'Point' type, then the child at index zero will be
    /// the 'x' member, and the child at index 1 will be the 'y' member
    /// (the child at index zero won't be a 'Point' instance).
    /// 
    /// Arrays have a preset number of children that can be accessed by
    /// index and will returns invalid child values for indexes that are
    /// out of bounds unless the \a synthetic_allowed is \b true. In this
    /// case the array can create 'synthetic' child values for indexes 
    /// that aren't in the array bounds using positive or negative 
    /// indexes.
    ///
    /// @param[in] idx
    ///     The index of the child value to get
    ///
    /// @param[in] use_dynamic
    ///     An enumeration that specifies wether to get dynamic values,
    ///     and also if the target can be run to figure out the dynamic
    ///     type of the child value.
    ///
    /// @param[in] synthetic_allowed
    ///     If \b true, then allow child values to be created by index
    ///     for pointers and arrays for indexes that normally wouldn't
    ///     be allowed.
    ///
    /// @return
    ///     A new SBValue object that represents the child member value.
    //------------------------------------------------------------------
    lldb::SBValue
    GetChildAtIndex (uint32_t idx, 
                     lldb::DynamicValueType use_dynamic,
                     bool can_create_synthetic);

    // Matches children of this object only and will match base classes and
    // member names if this is a clang typed object.
    uint32_t
    GetIndexOfChildWithName (const char *name);

    // Matches child members of this object and child members of any base
    // classes.
    lldb::SBValue
    GetChildMemberWithName (const char *name);

    // Matches child members of this object and child members of any base
    // classes.
    lldb::SBValue
    GetChildMemberWithName (const char *name, lldb::DynamicValueType use_dynamic);
    
    // Expands nested expressions like .a->b[0].c[1]->d
    lldb::SBValue
    GetValueForExpressionPath(const char* expr_path);
    
    lldb::SBValue
    AddressOf();
    
    lldb::addr_t
    GetLoadAddress();
    
    lldb::SBAddress
    GetAddress();

    //------------------------------------------------------------------
    /// Get an SBData wrapping what this SBValue points to.
    ///
    /// This method will dereference the current SBValue, if its
    /// data type is a T* or T[], and extract item_count elements
    /// of type T from it, copying their contents in an SBData. 
    ///
    /// @param[in] item_idx
    ///     The index of the first item to retrieve. For an array
    ///     this is equivalent to array[item_idx], for a pointer
    ///     to *(pointer + item_idx). In either case, the measurement
    ///     unit for item_idx is the sizeof(T) rather than the byte
    ///
    /// @param[in] item_count
    ///     How many items should be copied into the output. By default
    ///     only one item is copied, but more can be asked for.
    ///
    /// @return
    ///     An SBData with the contents of the copied items, on success.
    ///     An empty SBData otherwise.
    //------------------------------------------------------------------
    lldb::SBData
    GetPointeeData (uint32_t item_idx = 0,
                    uint32_t item_count = 1);
    
    //------------------------------------------------------------------
    /// Get an SBData wrapping the contents of this SBValue.
    ///
    /// This method will read the contents of this object in memory
    /// and copy them into an SBData for future use. 
    ///
    /// @return
    ///     An SBData with the contents of this SBValue, on success.
    ///     An empty SBData otherwise.
    //------------------------------------------------------------------
    lldb::SBData
    GetData ();
    
    bool
    SetData (lldb::SBData &data, lldb::SBError& error);
    
    lldb::SBDeclaration
    GetDeclaration ();
    
    //------------------------------------------------------------------
    /// Find out if a SBValue might have children.
    ///
    /// This call is much more efficient than GetNumChildren() as it
    /// doesn't need to complete the underlying type. This is designed
    /// to be used in a UI environment in order to detect if the
    /// disclosure triangle should be displayed or not.
    ///
    /// This function returns true for class, union, structure,
    /// pointers, references, arrays and more. Again, it does so without
    /// doing any expensive type completion.
    ///
    /// @return
    ///     Returns \b true if the SBValue might have children, or \b
    ///     false otherwise.
    //------------------------------------------------------------------
    bool
    MightHaveChildren ();

    uint32_t
    GetNumChildren ();

    void *
    GetOpaqueType();

    lldb::SBTarget
    GetTarget();
    
    lldb::SBProcess
    GetProcess();
    
    lldb::SBThread
    GetThread();

    lldb::SBFrame
    GetFrame();
    
    lldb::SBValue
    Dereference ();

    bool
    TypeIsPointerType ();
    
    lldb::SBType
    GetType();

    bool
    GetDescription (lldb::SBStream &description);

    bool
    GetExpressionPath (lldb::SBStream &description);
    
    bool
    GetExpressionPath (lldb::SBStream &description, 
                       bool qualify_cxx_base_classes);

    SBValue (const lldb::ValueObjectSP &value_sp);

    //------------------------------------------------------------------
    /// Watch this value if it resides in memory.
    ///
    /// Sets a watchpoint on the value.
    ///
    /// @param[in] resolve_location
    ///     Resolve the location of this value once and watch its address.
    ///     This value must currently be set to \b true as watching all
    ///     locations of a variable or a variable path is not yet supported,
    ///     though we plan to support it in the future.
    ///
    /// @param[in] read
    ///     Stop when this value is accessed.
    ///
    /// @param[in] write
    ///     Stop when this value is modified
    ///
    /// @param[out]
    ///     An error object. Contains the reason if there is some failure.
    ///
    /// @return
    ///     An SBWatchpoint object. This object might not be valid upon
    ///     return due to a value not being contained in memory, too 
    ///     large, or watchpoint resources are not available or all in
    ///     use.
    //------------------------------------------------------------------
    lldb::SBWatchpoint
    Watch (bool resolve_location, bool read, bool write, SBError &error);

    // Backward compatibility fix in the interim.
    lldb::SBWatchpoint
    Watch (bool resolve_location, bool read, bool write);

    //------------------------------------------------------------------
    /// Watch this value that this value points to in memory
    ///
    /// Sets a watchpoint on the value.
    ///
    /// @param[in] resolve_location
    ///     Resolve the location of this value once and watch its address.
    ///     This value must currently be set to \b true as watching all
    ///     locations of a variable or a variable path is not yet supported,
    ///     though we plan to support it in the future.
    ///
    /// @param[in] read
    ///     Stop when this value is accessed.
    ///
    /// @param[in] write
    ///     Stop when this value is modified
    ///
    /// @param[out]
    ///     An error object. Contains the reason if there is some failure.
    ///
    /// @return
    ///     An SBWatchpoint object. This object might not be valid upon
    ///     return due to a value not being contained in memory, too 
    ///     large, or watchpoint resources are not available or all in
    ///     use.
    //------------------------------------------------------------------
    lldb::SBWatchpoint
    WatchPointee (bool resolve_location, bool read, bool write, SBError &error);

    //------------------------------------------------------------------
    /// Same as the protected version of GetSP that takes a locker, except that we make the
    /// locker locally in the function.  Since the Target API mutex is recursive, and the
    /// StopLocker is a read lock, you can call this function even if you are already
    /// holding the two above-mentioned locks.
    ///
    /// @return
    ///     A ValueObjectSP of the best kind (static, dynamic or synthetic) we
    ///     can cons up, in accordance with the SBValue's settings.
    //------------------------------------------------------------------
    lldb::ValueObjectSP
    GetSP () const;

protected:
    friend class SBBlock;
    friend class SBFrame;
    friend class SBTarget;
    friend class SBThread;
    friend class SBValueList;

    //------------------------------------------------------------------
    /// Get the appropriate ValueObjectSP from this SBValue, consulting the
    /// use_dynamic and use_synthetic options passed in to SetSP when the
    /// SBValue's contents were set.  Since this often requires examining memory,
    /// and maybe even running code, it needs to acquire the Target API and Process StopLock.
    /// Those are held in an opaque class ValueLocker which is currently local to SBValue.cpp.
    /// So you don't have to get these yourself just default construct a ValueLocker, and pass it into this.
    /// If we need to make a ValueLocker and use it in some other .cpp file, we'll have to move it to
    /// ValueObject.h/cpp or somewhere else convenient.  We haven't needed to so far.
    ///
    /// @param[in] value_locker
    ///     An object that will hold the Target API, and Process RunLocks, and
    ///     auto-destroy them when it goes out of scope.  Currently this is only useful in
    ///     SBValue.cpp.
    ///
    /// @return
    ///     A ValueObjectSP of the best kind (static, dynamic or synthetic) we
    ///     can cons up, in accordance with the SBValue's settings.
    //------------------------------------------------------------------
    lldb::ValueObjectSP
    GetSP (ValueLocker &value_locker) const;
    
    // these calls do the right thing WRT adjusting their settings according to the target's preferences
    void
    SetSP (const lldb::ValueObjectSP &sp);

    void
    SetSP (const lldb::ValueObjectSP &sp, bool use_synthetic);
    
    void
    SetSP (const lldb::ValueObjectSP &sp, lldb::DynamicValueType use_dynamic);

    void
    SetSP (const lldb::ValueObjectSP &sp, lldb::DynamicValueType use_dynamic, bool use_synthetic);
    
    void
    SetSP (const lldb::ValueObjectSP &sp, lldb::DynamicValueType use_dynamic, bool use_synthetic, const char *name);
    
private:
    typedef std::shared_ptr<ValueImpl> ValueImplSP;
    ValueImplSP m_opaque_sp;
    
    void
    SetSP (ValueImplSP impl_sp);
};

} // namespace lldb

#endif  // LLDB_SBValue_h_