1 files changed, 94 insertions, 0 deletions
diff --git a/json/public.go b/json/public.go
new file mode 100644
index 0000000..8dc4a36
--- /dev/null
+++ b/json/public.go
@@ -0,0 +1,94 @@
+package json
+
+import (
+	"fmt"
+	"io/ioutil"
+	"os"
+
+	"github.com/hashicorp/hcl/v2"
+)
+
+// Parse attempts to parse the given buffer as JSON and, if successful, returns
+// a hcl.File for the HCL configuration represented by it.
+//
+// This is not a generic JSON parser. Instead, it deals only with the profile
+// of JSON used to express HCL configuration.
+//
+// The returned file is valid only if the returned diagnostics returns false
+// from its HasErrors method. If HasErrors returns true, the file represents
+// the subset of data that was able to be parsed, which may be none.
+func Parse(src []byte, filename string) (*hcl.File, hcl.Diagnostics) {
+	rootNode, diags := parseFileContent(src, filename)
+
+	switch rootNode.(type) {
+	case *objectVal, *arrayVal:
+		// okay
+	default:
+		diags = diags.Append(&hcl.Diagnostic{
+			Severity: hcl.DiagError,
+			Summary:  "Root value must be object",
+			Detail:   "The root value in a JSON-based configuration must be either a JSON object or a JSON array of objects.",
+			Subject:  rootNode.StartRange().Ptr(),
+		})
+
+		// Since we've already produced an error message for this being
+		// invalid, we'll return an empty placeholder here so that trying to
+		// extract content from our root body won't produce a redundant
+		// error saying the same thing again in more general terms.
+		fakePos := hcl.Pos{
+			Byte:   0,
+			Line:   1,
+			Column: 1,
+		}
+		fakeRange := hcl.Range{
+			Filename: filename,
+			Start:    fakePos,
+			End:      fakePos,
+		}
+		rootNode = &objectVal{
+			Attrs:     []*objectAttr{},
+			SrcRange:  fakeRange,
+			OpenRange: fakeRange,
+		}
+	}
+
+	file := &hcl.File{
+		Body: &body{
+			val: rootNode,
+		},
+		Bytes: src,
+		Nav:   navigation{rootNode},
+	}
+	return file, diags
+}
+
+// ParseFile is a convenience wrapper around Parse that first attempts to load
+// data from the given filename, passing the result to Parse if successful.
+//
+// If the file cannot be read, an error diagnostic with nil context is returned.
+func ParseFile(filename string) (*hcl.File, hcl.Diagnostics) {
+	f, err := os.Open(filename)
+	if err != nil {
+		return nil, hcl.Diagnostics{
+			{
+				Severity: hcl.DiagError,
+				Summary:  "Failed to open file",
+				Detail:   fmt.Sprintf("The file %q could not be opened.", filename),
+			},
+		}
+	}
+	defer f.Close()
+
+	src, err := ioutil.ReadAll(f)
+	if err != nil {
+		return nil, hcl.Diagnostics{
+			{
+				Severity: hcl.DiagError,
+				Summary:  "Failed to read file",
+				Detail:   fmt.Sprintf("The file %q was opened, but an error occured while reading it.", filename),
+			},
+		}
+	}
+
+	return Parse(src, filename)
+}