From fd35a003818656e649491dc2af242d36a60d7ed1 Mon Sep 17 00:00:00 2001
From: Matthias Beyer <mail@beyermatthias.de>
Date: Mon, 9 Nov 2015 00:03:10 +0100
Subject: [PATCH] Implement JSON to FileHeaderData parser

---
 src/storage/file.rs        |  4 +--
 src/storage/json/parser.rs | 53 ++++++++++++++++++++++++++++++++------
 src/storage/parser.rs      |  8 +++---
 3 files changed, 51 insertions(+), 14 deletions(-)

diff --git a/src/storage/file.rs b/src/storage/file.rs
index 0270f5ea..008b2d9c 100644
--- a/src/storage/file.rs
+++ b/src/storage/file.rs
@@ -175,10 +175,10 @@ pub struct File<D: FileData> {
     id      : String
 }
 
-impl<D: FileData> File<D> {
+impl<'a, D: FileData> File<D> {
 
     fn new<HP, DP>(prs: &Parser<HP, DP>, path: &String) -> Result<File<D>, ParserError>
-        where HP: FileHeaderParser,
+        where HP: FileHeaderParser<'a>,
               DP: FileDataParser<D>,
     {
         File::<D>::read_file(path).and_then(|p| prs.read(p))
diff --git a/src/storage/json/parser.rs b/src/storage/json/parser.rs
index 0e275ca3..f915e7fe 100644
--- a/src/storage/json/parser.rs
+++ b/src/storage/json/parser.rs
@@ -1,14 +1,17 @@
-use serde_json::Value;
+use serde_json::{Value, from_str};
+use serde_json::error::Result as R;
 
-use super::parser;
+use super::super::parser::{FileHeaderParser, ParserError};
+use super::super::file::{FileHeaderSpec, FileHeaderData};
 
-struct JsonHeaderParser {
-    spec: &FileHeaderSpec,
+
+struct JsonHeaderParser<'a> {
+    spec: &'a FileHeaderSpec,
 }
 
-impl FileHeaderParser for JsonHeaderParser {
+impl<'a> FileHeaderParser<'a> for JsonHeaderParser<'a> {
 
-    fn new(spec: &FileHeaderSpec) -> JsonHeaderParser {
+    fn new(spec: &'a FileHeaderSpec) -> JsonHeaderParser<'a> {
         JsonHeaderParser {
             spec: spec
         }
@@ -17,9 +20,17 @@ impl FileHeaderParser for JsonHeaderParser {
     fn read(&self, string: Option<String>)
         -> Result<FileHeaderData, ParserError>
     {
-        if let Ok(content) = data = serde_json::from_str(&string[..]) {
+        if (string.is_some()) {
+            let s = string.unwrap();
+            debug!("Deserializing: {}", s);
+            let fromstr : R<Value> = from_str(&s[..]);
+            if let Ok(content) = fromstr {
+                Ok(visit_json(&content))
+            } else {
+                Err(ParserError::short("Unknown JSON parser error", s.clone(), 0))
+            }
         } else {
-            ParserError::short("Unknown JSON parser error", string.clone(), 0)
+            Ok(FileHeaderData::Null)
         }
     }
 
@@ -28,3 +39,29 @@ impl FileHeaderParser for JsonHeaderParser {
 
 }
 
+// TODO: This function must be able to return a parser error
+fn visit_json(v: &Value) -> FileHeaderData {
+    match v {
+        &Value::Null             => FileHeaderData::Null,
+        &Value::Bool(b)          => FileHeaderData::Bool(b),
+        &Value::I64(i)           => FileHeaderData::Integer(i),
+        &Value::U64(u)           => FileHeaderData::UInteger(u),
+        &Value::F64(f)           => FileHeaderData::Float(f),
+        &Value::String(ref s)        => FileHeaderData::Text(s.clone()),
+        &Value::Array(ref vec)       => {
+            FileHeaderData::Array {
+                values: Box::new(vec.clone().into_iter().map(|i| visit_json(v)).collect())
+            }
+        },
+        &Value::Object(ref btree)    => {
+            FileHeaderData::Map{
+                keys: btree.clone().iter().map(|(k, v)|
+                    FileHeaderData::Key {
+                        name: k.clone(),
+                        value: Box::new(visit_json(v)),
+                    }
+                ).collect()
+            }
+        }
+    }
+}
diff --git a/src/storage/parser.rs b/src/storage/parser.rs
index ae6198a3..f470c779 100644
--- a/src/storage/parser.rs
+++ b/src/storage/parser.rs
@@ -74,8 +74,8 @@ impl Display for ParserError {
 }
 
 
-pub trait FileHeaderParser : Sized {
-    fn new(spec: &FileHeaderSpec) -> Self;
+pub trait FileHeaderParser<'a> : Sized {
+    fn new(spec: &'a FileHeaderSpec) -> Self;
     fn read(&self, string: Option<String>) -> Result<FileHeaderData, ParserError>;
     fn write(&self, data: &FileHeaderData) -> Result<String, ParserError>;
 }
@@ -94,8 +94,8 @@ pub struct Parser<HP, DP>
     datap : DP,
 }
 
-impl<HP, DP> Parser<HP, DP> where
-    HP: FileHeaderParser,
+impl<'a, HP, DP> Parser<HP, DP> where
+    HP: FileHeaderParser<'a>,
 {
 
     fn new(headerp: HP, datap: DP) -> Parser<HP, DP> {