Prevent adding a PeakList to two different images

This is kind-of-OK in C, but will break Julia's memory management.

2 files changed, 17 insertions, 3 deletions

diff --git a/julia/CrystFEL/src/image.jl b/julia/CrystFEL/src/image.jl
index 868afdc4..4f126c28 100644
--- a/julia/CrystFEL/src/image.jl
+++ b/julia/CrystFEL/src/image.jl
@@ -53,7 +53,7 @@ function Base.getproperty(image::Image, name::Symbol)
                 if pl == C_NULL
                     throw(ErrorException("Image doesn't have a peak list"))
                 else
-                    PeakList(pl)
+                    PeakList(pl, true)
                 end
             end
         else
@@ -70,7 +70,12 @@ function Base.setproperty!(image::Image, name::Symbol, val)
         idata = unsafe_load(image.internalptr)
         if name === :peaklist
             if val isa PeakList
+                if val.in_image
+                    throw(ArgumentError("PeakList is already in an image.  "*
+                                        "Add a copy (use `deepcopy`) instead."))
+                end
                 setproperty!(idata, name, val.internalptr)
+                val.in_image = true
                 unsafe_store!(image.internalptr, idata)
             else
                 throw(ArgumentError("Must be a PeakList"))
diff --git a/julia/CrystFEL/src/peaklist.jl b/julia/CrystFEL/src/peaklist.jl
index f8c9b407..1735de5e 100644
--- a/julia/CrystFEL/src/peaklist.jl
+++ b/julia/CrystFEL/src/peaklist.jl
@@ -14,8 +14,9 @@ end
 
 mutable struct InternalPeakList end
 
-struct PeakList
+mutable struct PeakList
     internalptr::Ptr{InternalPeakList}
+    in_image   # if true, this PeakList belongs to an Image struct
 end
 
 
@@ -24,10 +25,18 @@ function PeakList()
     if out == C_NULL
         throw(ArgumentError("Failed to create peak list"))
     end
-    PeakList(out)
+    PeakList(out, false)
 end
 
 
+function Base.deepcopy(peaklist::PeakList)
+    out = @ccall libcrystfel.image_feature_list_copy(peaklist.internalptr::Ptr{InternalPeakList})::Ptr{InternalPeakList}
+    if out == C_NULL
+        throw(ErrorException("Failed to copy peak list"))
+    end
+    PeakList(out, false)
+end
+
 function Base.length(peaklist::PeakList)
     @ccall libcrystfel.image_feature_count(peaklist.internalptr::Ptr{InternalPeakList})::Cint
 end