Merge pull request #19959 from JuliaLang/ksh/blobshow

Show + isbinary method for GitBlob, and a doc link

base/libgit2/blob.jl

@@ -8,10 +8,42 @@ function Base.length(blob::GitBlob)
     return ccall((:git_blob_rawsize, :libgit2), Int64, (Ptr{Void},), blob.ptr)
 end
 
+"""
+Use a heuristic to guess if a file is binary: searching for NULL bytes and
+looking for a reasonable ratio of printable to non-printable characters among
+the first 8000 bytes.
+"""
+function isbinary(blob::GitBlob)
+    bin_flag = ccall((:git_blob_is_binary, :libgit2), Int64, (Ptr{Void},), blob.ptr)
+    return bin_flag == 1
+end
+
 function lookup(repo::GitRepo, oid::GitHash)
     blob_ptr_ptr = Ref{Ptr{Void}}(C_NULL)
     @check ccall((:git_blob_lookup, :libgit2), Cint,
                   (Ptr{Ptr{Void}}, Ptr{Void}, Ref{GitHash}),
                    blob_ptr_ptr, repo.ptr, Ref(oid))
     return GitBlob(blob_ptr_ptr[])
 end
+
+function GitBlob(repo::GitRepo, path::AbstractString)
+    blob_id_ptr = Ref(GitHash())
+    @check ccall((:git_blob_create_fromdisk, :libgit2), Cint,
+                 (Ptr{GitHash}, Ptr{Void}, Ptr{UInt8}), blob_id_ptr,
+                 repo.ptr, path)
+    blob = get(GitBlob, repo, blob_id_ptr[])
+    return blob
+end
+
+function Base.show(io::IO, blob::GitBlob)
+    if !isbinary(blob)
+        conts   = split(content(blob), "\n")
+        showlen = max(len(conts), 3)
+        print(io, "GitBlob:\nBlob id: ", GitHash(blob.ptr), "\nContents:\n")
+        for i in 1:showlen
+            print(io, conts[i],"\n")
+        end
+    else
+        print(io, "GitBlob:\nBlob id: ", GitHash(blob.ptr), "\nContents are binary.")
+    end
+end

base/libgit2/types.jl

@@ -348,7 +348,7 @@ end
     LibGit2.RebaseOperation
 
 Describes a single instruction/operation to be performed during the rebase.
-Matches the `git_rebase_operation` struct.
+Matches the [`git_rebase_operation`](https://libgit2.github.com/libgit2/#HEAD/type/git_rebase_operation_t) struct.
 """
 immutable RebaseOperation
     optype::Cint
@@ -361,7 +361,7 @@ Base.show(io::IO, rbo::RebaseOperation) = print(io, "RebaseOperation($(string(rb
     LibGit2.StatusOptions
 
 Options to control how `git_status_foreach_ext()` will issue callbacks.
-Matches the `git_status_options` struct.
+Matches the [`git_status_opt_t`](https://libgit2.github.com/libgit2/#HEAD/type/git_status_opt_t) struct.
 """
 @kwdef immutable StatusOptions
     version::Cuint           = 1

test/libgit2.jl

@@ -437,6 +437,24 @@ mktempdir() do dir
                 close(repo)
             end
         end
+
+        @testset "blobs" begin
+            repo = LibGit2.GitRepo(cache_repo)
+            try
+                # clear out the "GitHash( )" part
+                hash_string = sprint(show, commit_oid1)[9:end]
+                hash_string = strip(hash_string, ')')
+                blob_file   = joinpath(cache_repo,".git/objects", hash_string[1:2], hash_string[3:end])
+                blob = LibGit2.GitBlob(repo, blob_file)
+                @test LibGit2.isbinary(blob)
+                blob_show_strs = split(sprint(show, blob), "\n")
+                @test blob_show_strs[1] == "GitBlob:"
+                @test contains(blob_show_strs[2], "Blob id:")
+                @test blob_show_strs[3] == "Contents are binary."
+            finally
+                close(repo)
+            end
+        end
     end
 
     @testset "Fetch from cache repository" begin