c2pa-rs

commit 4356a1bc85404610cdb00d9a80a7f354e0c962b8
parent 573bc19b17cc0482e9408a1bf7187b53a46ea8ec
Author: nick <nick.libraries@gmail.com>
Date:   Tue, 18 Jun 2024 09:54:15 -0400

Add iterators over manifests and resources in unstable API (#482)

* Add `Reader::iter_manifests` + `ResourceSource::iter_resources` + pub `ResourceStore`

* Move iter_resources to Manifest
Diffstat:
M
sdk/src/lib.rs
 | 
2
+-
M
sdk/src/manifest.rs
 | 
10
+++++++++-
A
sdk/src/manifest2.rs
 | 
1
+
M
sdk/src/reader.rs
 | 
5
+++++
M
sdk/src/resource_store.rs
 | 
25
++++++++++++++++++++++++-

5 files changed, 40 insertions(+), 3 deletions(-)
diff --git a/sdk/src/lib.rs b/sdk/src/lib.rs
@@ -129,7 +129,7 @@ pub use manifest_store::ManifestStore;
 pub use manifest_store_report::ManifestStoreReport;
 #[cfg(feature = "unstable_api")]
 pub use reader::Reader;
-pub use resource_store::ResourceRef;
+pub use resource_store::{ResourceRef, ResourceStore};
 pub use signer::{AsyncSigner, RemoteSigner, Signer};
 pub use signing_alg::SigningAlg;
 pub use utils::mime::format_from_path;
diff --git a/sdk/src/manifest.rs b/sdk/src/manifest.rs
@@ -34,7 +34,7 @@ use crate::{
     ingredient::Ingredient,
     jumbf,
     manifest_assertion::ManifestAssertion,
-    resource_store::{skip_serializing_resources, ResourceRef, ResourceStore},
+    resource_store::{mime_from_uri, skip_serializing_resources, ResourceRef, ResourceStore},
     salt::DefaultSalt,
     store::Store,
     AsyncSigner, ClaimGeneratorInfo, HashRange, ManifestAssertionKind, RemoteSigner, Signer,
@@ -451,6 +451,14 @@ impl Manifest {
         self.signature_info.to_owned().and_then(|sig| sig.time)
     }
 
+    /// Returns an iterator over [`ResourceRef`][ResourceRef]s.
+    pub fn iter_resources(&self) -> impl Iterator<Item = ResourceRef> + '_ {
+        self.resources
+            .resources()
+            .keys()
+            .map(|uri| ResourceRef::new(mime_from_uri(uri), uri.to_owned()))
+    }
+
     /// Return an immutable reference to the manifest resources
     pub fn resources(&self) -> &ResourceStore {
         &self.resources
diff --git a/sdk/src/manifest2.rs b/sdk/src/manifest2.rs
@@ -0,0 +1 @@
+
diff --git a/sdk/src/reader.rs b/sdk/src/reader.rs
@@ -186,6 +186,11 @@ impl Reader {
         self.manifest_store.active_label()
     }
 
+    /// Returns an iterator over [`Manifest`][Manifest]s.
+    pub fn iter_manifests(&self) -> impl Iterator<Item = &Manifest> + '_ {
+        self.manifest_store.manifests().values()
+    }
+
     /// Return a [`Manifest`] for a given label if it exists.
     /// # Arguments
     /// * `label` - The label of the requested [`Manifest`]
diff --git a/sdk/src/resource_store.rs b/sdk/src/resource_store.rs
@@ -28,7 +28,13 @@ use serde::{Deserialize, Serialize};
 
 #[cfg(feature = "unstable_api")]
 use crate::asset_io::CAIRead;
-use crate::{assertions::AssetType, claim::Claim, hashed_uri::HashedUri, Error, Result};
+use crate::{
+    assertions::{labels, AssetType},
+    claim::Claim,
+    hashed_uri::HashedUri,
+    jumbf::labels::assertion_label_from_uri,
+    Error, Result,
+};
 
 /// Function that is used by serde to determine whether or not we should serialize
 /// resources based on the `serialize_resources` flag.
@@ -93,6 +99,8 @@ impl From<HashedUri> for UriOrResource {
 #[derive(Clone, Debug, Deserialize, Serialize, Eq, PartialEq)]
 #[cfg_attr(feature = "json_schema", derive(JsonSchema))]
 /// A reference to a resource to be used in JSON serialization.
+///
+/// The underlying data can be read as a stream via [`Reader::resource_to_stream`][crate::Reader::resource_to_stream].
 pub struct ResourceRef {
     /// The mime type of the referenced resource.
     pub format: String,
@@ -361,6 +369,7 @@ impl Default for ResourceStore {
 
 #[cfg(feature = "unstable_api")]
 pub trait ResourceResolver {
+    /// Read the data in a [`ResourceRef`][ResourceRef] via a stream.
     fn open(&self, reference: &ResourceRef) -> Result<Box<dyn CAIRead>>;
 }
 
@@ -373,6 +382,20 @@ impl ResourceResolver for ResourceStore {
     }
 }
 
+pub fn mime_from_uri(uri: &str) -> String {
+    if let Some(label) = assertion_label_from_uri(uri) {
+        if label.starts_with(labels::THUMBNAIL) {
+            // https://c2pa.org/specifications/specifications/1.0/specs/C2PA_Specification.html#_thumbnail
+            if let Some(ext) = label.rsplit('.').next() {
+                return format!("image/{ext}");
+            }
+        }
+    }
+
+    // Unknown binary data.
+    String::from("application/octet-stream")
+}
+
 #[cfg(test)]
 #[cfg(feature = "openssl_sign")]
 mod tests {