Mmap and ZipArchives adverse interaction

[TimG1964]

MWE:

using ZipArchives
using Mmap

function reading()
    io=open("simpleTest.xlsx")
    mm=Mmap.mmap(io)
    q = ZipArchives.ZipReader(mm)
    #q = ZipArchives.ZipReader(read("simpleTest.xlsx"))
    readme_n_lines = zip_openentry(q, "xl/worksheets/sheet1.xml") do z
        countlines(z)
    close(io)
    GC.gc()
    end
end

reading()

isfile("simpleTest.xlsx") && rm("simpleTest.xlsx")

does not work:

ERROR: LoadError: IOError: unlink("simpleTest.xlsx"): permission denied (EACCES)
Stacktrace:
  [1] uv_error
    @ .\libuv.jl:106 [inlined]
  [2] unlink(p::String)
    @ Base.Filesystem .\file.jl:1105
  [3] rm(path::String; force::Bool, recursive::Bool)
    @ Base.Filesystem .\file.jl:283
  [4] rm(path::String)
    @ Base.Filesystem .\file.jl:273
  [5] top-level scope
    @ c:\Users\tim\OneDrive\Documents\Julia\ZipArchives\TestMmap.jl:18
  [6] include(fname::String)
    @ Main .\sysimg.jl:38
  [7] run(debug_session::VSCodeDebugger.DebugAdapter.DebugSession, error_handler::VSCodeDebugger.var"#3#4"{String})
    @ VSCodeDebugger.DebugAdapter c:\Users\tim\.vscode\extensions\julialang.language-julia-1.144.2\scripts\packages\DebugAdapter\src\packagedef.jl:123
  [8] startdebugger()
    @ VSCodeDebugger c:\Users\tim\.vscode\extensions\julialang.language-julia-1.144.2\scripts\packages\VSCodeDebugger\src\VSCodeDebugger.jl:47
  [9] top-level scope
    @ c:\Users\tim\.vscode\extensions\julialang.language-julia-1.144.2\scripts\debugger\run_debugger.jl:12
 [10] include(mod::Module, _path::String)
    @ Base .\Base.jl:557
 [11] exec_options(opts::Base.JLOptions)
    @ Base .\client.jl:323
 [12] _start()
    @ Base .\client.jl:531
in expression starting at c:\Users\tim\OneDrive\Documents\Julia\ZipArchives\TestMmap.jl:18

If I swap the definition of q to be simply ZipArchives.ZipReader(read("simpleTest.xlsx")) then this works fine. Also if I mmap(open("simpleTest.xlsx")) and then close without invoking the ZipReader, this also works fine. It is only when I use ZipReader in combination with mmap that I get an error.

I am using Windows but the issue seems not to be replicated on Linux. I am trying to include this mmap use to restore the ability to read data too big to fit memory in XLSX.jl. Obviously, Windows is an important platform for this. Currently, this issue is causing package tests to fail.

Further discussion in Discourse here.

[nhz2]

Fixed in #95

[TimG1964]

Thanks for this!

Not a particular problem for me but I notice that ZipArchives.ZipReader is type unstable (at least the way I've been using it!) depending on whether I use read(), mmap() or FileArray()

julia> f= XLSX.open_or_read_xlsx(raw"C:\Users\tim\OneDrive\Documents\Julia\XLSX\grants100.xlsx", true, true, true)
XLSXFile("C:\Users\tim\OneDrive\Documents\Julia\XLSX\grants100.xlsx") containing 1 Worksheet
            sheetname size          range
-------------------------------------------------
    20250224 - grants 100x16        A1:P100

julia> f.io
25780 byte, 10 entry ZipArchives.ZipReader{Vector{UInt8}} # read()
total uncompressed size: 120932 bytes
  "[Content_Types].xml"
  "_rels/"
  "docProps/"
  "xl/"

julia> f= XLSX.open_or_read_xlsx(raw"C:\Users\tim\OneDrive\Documents\Julia\XLSX\grants100.xlsx", true, false, false)
XLSXFile("C:\Users\tim\OneDrive\Documents\Julia\XLSX\grants100.xlsx") containing 1 Worksheet
            sheetname size          range
-------------------------------------------------
    20250224 - grants 100x16        A1:P100


julia> f.io
25780 byte, 10 entry ZipArchives.ZipReader{XLSX.FileArray} # FileArray()
total uncompressed size: 120932 bytes
  "[Content_Types].xml"
  "_rels/"
  "docProps/"
  "xl/"

If I switch back to using mmap instead of FileArray this difference goes away:

julia> f.io
25780 byte, 10 entry ZipArchives.ZipReader{Vector{UInt8}} # mmap()
total uncompressed size: 120932 bytes
  "[Content_Types].xml"
  "_rels/"
  "docProps/"
  "xl/"

Using mmap is also very slightly faster than FileArray.