add support to download image

src/data/json.rs

@@ -0,0 +1,76 @@
+use crate::gettext;
+use crate::pixiv_link::PixivID;
+use crate::pixiv_link::ToPixivID;
+use json::JsonValue;
+use std::collections::HashMap;
+use std::ffi::OsStr;
+use std::fs::File;
+use std::fs::remove_file;
+use std::io::Write;
+use std::path::Path;
+
+pub trait ToJson {
+    fn to_json(&self) -> Option<JsonValue>;
+}
+
+/// Store metadata informations in JSON file
+pub struct JSONDataFile {
+    id: PixivID,
+    maps: HashMap<String, JsonValue>,
+}
+
+impl JSONDataFile {
+    pub fn new<T: ToPixivID>(id: T) -> Option<Self> {
+        let i = id.to_pixiv_id();
+        if i.is_none() {
+            return None;
+        }
+        Some(Self {
+            id: i.unwrap(),
+            maps: HashMap::new(),
+        })
+    }
+
+    pub fn save<S: AsRef<OsStr> + ?Sized>(&self, path: &S) -> bool {
+        let p = Path::new(path);
+        if p.exists() {
+            let r = remove_file(p);
+            if r.is_err() {
+                println!("{} {}", gettext("Failed to remove file:"), r.unwrap_err());
+                return false;
+            }
+        }
+        let value = self.to_json();
+        if value.is_none() {
+            return false;
+        }
+        let value = value.unwrap();
+        let f = File::create(p);
+        if f.is_err() {
+            println!("{} {}", gettext("Failed to create file:"), f.unwrap_err());
+            return false;
+        }
+        let mut f = f.unwrap();
+        let r = f.write(value.pretty(2).as_bytes());
+        if r.is_err() {
+            println!("{} {}", gettext("Failed to write file:"), r.unwrap_err());
+            return false;
+        }
+        true
+    }
+}
+
+impl ToJson for JSONDataFile {
+    fn to_json(&self) -> Option<JsonValue> {
+        let mut value = json::object! {};
+        if value.insert("id", self.id.to_json()).is_err() {
+            return None;
+        }
+        for (k, v) in self.maps.iter() {
+            if value.insert(k, v.clone()).is_err() {
+                return None;
+            }
+        }
+        Some(value)
+    }
+}

src/data/mod.rs

@@ -0,0 +1 @@
+pub mod json;