Make assets `PackageCompiler`-friendly

A possible solution to relocatablilty issues with the hardcoded paths.

Embeds the asset folder contents into the precompiled files. When the
original folder isn't available (due to relocation) creates a
scratchspace containing the original folder contents as uses that
instead.

Project.toml

@@ -13,6 +13,8 @@ Pkg = "44cfe95a-1eb2-52ea-b672-e2afdf69b78f"
 Printf = "de0858da-6303-5e67-8744-51eddeeeb8d7"
 REPL = "3fa0cd96-eef1-5676-8a61-b3b8758bbffb"
 Requires = "ae029012-a4dd-5104-9daa-d747884805df"
+SHA = "ea8e919c-243c-51af-8825-aaa63cd721ce"
+Scratch = "6c6a2e73-6563-6170-7368-637461726353"
 Serialization = "9e88b42a-f829-5b0c-bbe9-9e923198166b"
 YAML = "ddb6d928-2868-570f-bddf-ab3f9cf99eb6"
 
@@ -22,6 +24,7 @@ JSON = "0.21"
 Mustache = "0.4.1, 0.5, 1"
 Plots = "0.28, 0.29, 1.0"
 Requires = "1.0"
+Scratch = "1.1"
 YAML = "0.3, 0.4"
 julia = "1.2"
 

src/RelocatableFolders.jl

@@ -0,0 +1,57 @@
+module RelocatableFolders
+
+import Scratch, SHA
+
+export @folder_str
+
+macro folder_str(path)
+    dir = string(__source__.file)
+    dir = isfile(dir) ? dirname(dir) : pwd()
+    return :($(Folder)($__module__, $dir, $(esc(path))))
+end
+
+struct Folder <: AbstractString
+    mod::Module
+    path::String
+    hash::String
+    files::Dict{String,Vector{UInt8}}
+
+    function Folder(mod::Module, dir, path::AbstractString)
+        path = isabspath(path) ? path : normpath(joinpath(dir, path))
+        isdir(path) || throw(ArgumentError("not a directory: `$path`"))
+        files = Dict{String,Vector{UInt8}}()
+        ctx = SHA.SHA1_CTX()
+        for (root, _, fs) in walkdir(path), f in fs
+            fullpath = joinpath(root, f)
+            include_dependency(fullpath)
+            SHA.update!(ctx, codeunits(fullpath))
+            content = read(fullpath)
+            SHA.update!(ctx, content)
+            files[relpath(fullpath, path)] = content
+        end
+        return new(mod, path, string(Base.SHA1(SHA.digest!(ctx))), files)
+    end
+end
+
+Base.show(io::IO, path::Folder) = print(io, repr(path.path))
+Base.ncodeunits(f::Folder) = ncodeunits(getpath(f))
+Base.isvalid(f::Folder, index::Integer) = isvalid(getpath(f), index)
+Base.iterate(f::Folder) = iterate(getpath(f))
+Base.iterate(f::Folder, state::Integer) = iterate(getpath(f), state)
+Base.String(f::Folder) = String(getpath(f))
+
+function getpath(f::Folder)
+    isdir(f.path) && return f.path
+    dir = Scratch.get_scratch!(f.mod, f.hash)
+    if !isempty(f.files) && !ispath(joinpath(dir, first(keys(f.files))))
+        cd(dir) do
+            for (file, blob) in f.files
+                mkpath(dirname(file))
+                write(file, blob)
+            end
+        end
+    end
+    return dir
+end
+
+end # module

src/Weave.jl

@@ -2,13 +2,15 @@ module Weave
 
 using Highlights, Mustache, Requires, Pkg, REPL
 
+include("RelocatableFolders.jl")
+using .RelocatableFolders
 
 # directories
 const PKG_DIR = normpath(@__DIR__, "..")
-const TEMPLATE_DIR = normpath(PKG_DIR, "templates")
-const STYLESHEET_DIR = normpath(PKG_DIR, "stylesheets")
+const TEMPLATE_DIR = folder"../templates"
+const STYLESHEET_DIR = folder"../stylesheets"
 # keeps paths of sample documents for easy try
-const EXAMPLE_FOLDER = normpath(PKG_DIR, "examples")
+const EXAMPLE_FOLDER = folder"../examples"
 
 # constant names
 const WEAVE_OPTION_NAME = "weave_options"