Enable true streaming with a buffer-based fallback

When using libvips version 8.13 or higher.

src/api/CMakeLists.txt

@@ -3,6 +3,7 @@ set(HEADERS
         exceptions/large.h
         exceptions/unreadable.h
         exceptions/unsupported.h
+        io/blob.h
         io/source.h
         io/target.h
         parsers/color.h
@@ -77,18 +78,17 @@ target_link_libraries(${PROJECT_NAME}
             ${VIPS_LDFLAGS}
         )
 
-# TODO(kleisauke): Enable once magickload_source is supported in libvips
-#if (VIPS_VERSION VERSION_GREATER_EQUAL 8.13)
-#    target_compile_definitions(${PROJECT_NAME}
-#            PUBLIC
-#                WESERV_ENABLE_TRUE_STREAMING
-#            )
-#endif()
+if (VIPS_VERSION VERSION_GREATER_EQUAL 8.13)
+    target_compile_definitions(${PROJECT_NAME}
+            PUBLIC
+                WESERV_ENABLE_TRUE_STREAMING
+            )
+endif()
 
 set_target_properties(${PROJECT_NAME}
         PROPERTIES
             VERSION ${PROJECT_VERSION}
-            SOVERSION 5
+            SOVERSION ${PROJECT_VERSION_MAJOR}
         )
 
 install(TARGETS ${PROJECT_NAME}

src/api/api_manager_impl.cpp

@@ -78,7 +78,8 @@ ApiManagerImpl::ApiManagerImpl(std::unique_ptr<ApiEnvInterface> env)
         vips_error_clear();
 
         env_->log_error("error: Unable to start up libvips: " + error);
-    }  // LCOV_EXCL_STOP
+        // LCOV_EXCL_STOP
+    }
 }
 
 ApiManagerImpl::~ApiManagerImpl() {
@@ -142,8 +143,8 @@ Status ApiManagerImpl::exception_handler(const std::string &query) {
 
         return {Status::Code::Unknown, error_str,
                 Status::ErrorCause::Application};
+        // LCOV_EXCL_STOP
     }
-    // LCOV_EXCL_STOP
 }
 
 utils::Status ApiManagerImpl::process(const std::string &query,

src/api/io/blob.h

@@ -0,0 +1,81 @@
+#pragma once
+
+#include <vips/vips8>
+
+namespace weserv::api::io {
+
+class Blob {
+ public:
+    explicit Blob(VipsBlob *blob = nullptr) : blob_(blob) {}
+
+    // copy constructor
+    Blob(const Blob &a) : blob_(a.blob_) {
+        reference();
+    }
+
+    // this mustn't be virtual: we want this class to only be a pointer,
+    // no vtable allowed
+    ~Blob() {
+        unreference();
+    }
+
+    // assignment ... we must delete the old ref
+    Blob &operator=(const Blob &a) {
+        // check whether we are already referencing this object -
+        // if so make this a null op. This will also deal with
+        // self-assignment.
+        if (blob_ != a.blob_) {
+            unreference();
+
+            blob_ = a.blob_;
+
+            reference();
+        }
+
+        return *this;
+    }
+
+    /**
+     * Get the underlying VipsBlob pointer.
+     * @return The underlying VipsBlob pointer.
+     */
+    VipsBlob *get_blob() const {
+        return blob_;
+    }
+
+    /**
+     * Get the data from a Blob.
+     * @param length Return number of bytes of data.
+     * @return The data.
+     */
+    const void *get_blob(size_t *length) const {
+        return vips_blob_get(blob_, length);
+    }
+
+    /**
+     * @return true if this Blob is a nullptr.
+     */
+    bool is_null() const {
+        return blob_ == nullptr;
+    }
+
+ private:
+    /**
+     * The underlying VipsBlob pointer, can be nullptr.
+     */
+    VipsBlob *blob_;
+
+    inline void unreference() {
+        if (blob_ != nullptr) {
+            vips_area_unref(reinterpret_cast<VipsArea *>(blob_));
+        }
+    }
+
+    inline void reference() {
+        if (blob_ != nullptr) {
+            vips_area_copy(reinterpret_cast<VipsArea *>(blob_));
+        }
+    }
+};
+
+}  // namespace weserv::api::io

src/api/io/source.cpp

@@ -59,8 +59,9 @@ Source Source::new_from_pointer(std::unique_ptr<io::SourceInterface> source) {
         g_object_new(WESERV_TYPE_SOURCE, "source", source.get(), nullptr));
 
     if (vips_object_build(VIPS_OBJECT(weserv_source)) != 0) {
-        VIPS_UNREF(weserv_source);
+        VIPS_UNREF(weserv_source);  // LCOV_EXCL_START
         throw vips::VError();
+        // LCOV_EXCL_STOP
     }
 
     return Source(weserv_source);
@@ -70,18 +71,18 @@ Source Source::new_from_file(const std::string &filename) {
     VipsSource *source = vips_source_new_from_file(filename.c_str());
 
     if (source == nullptr) {
-        throw vips::VError();
+        throw vips::VError();  // LCOV_EXCL_LINE
     }
 
     return Source(source);
 }
 
 Source Source::new_from_buffer(const std::string &buffer) {
     VipsSource *source =
-        vips_source_new_from_memory(buffer.c_str(), buffer.size());
+        vips_source_new_from_memory(buffer.data(), buffer.size());
 
     if (source == nullptr) {
-        throw vips::VError();
+        throw vips::VError();  // LCOV_EXCL_LINE
     }
 
     return Source(source);

src/api/io/target.cpp

@@ -17,6 +17,7 @@ static gint64 weserv_target_write_wrapper(VipsTarget *target, const void *data,
     return weserv_target->write(data, length);
 }
 
+// LCOV_EXCL_START
 static gint64 weserv_target_read_wrapper(VipsTarget *target, void *data,
                                          size_t length) {
     auto weserv_target = WESERV_TARGET(target)->target;
@@ -30,6 +31,7 @@ static gint64 weserv_target_seek_wrapper(VipsTarget *target, gint64 offset,
 
     return weserv_target->seek(offset, whence);
 }
+// LCOV_EXCL_STOP
 
 static int weserv_target_end_wrapper(VipsTarget *target) {
     auto weserv_target = WESERV_TARGET(target)->target;
@@ -71,8 +73,9 @@ Target Target::new_to_pointer(std::unique_ptr<io::TargetInterface> target) {
         g_object_new(WESERV_TYPE_TARGET, "target", target.get(), nullptr));
 
     if (vips_object_build(VIPS_OBJECT(weserv_target)) != 0) {
-        VIPS_UNREF(weserv_target);
+        VIPS_UNREF(weserv_target);  // LCOV_EXCL_START
         throw vips::VError();
+        // LCOV_EXCL_STOP
     }
 
     return Target(weserv_target);
@@ -82,7 +85,7 @@ Target Target::new_to_file(const std::string &filename) {
     VipsTarget *target = vips_target_new_to_file(filename.c_str());
 
     if (target == nullptr) {
-        throw vips::VError();
+        throw vips::VError();  // LCOV_EXCL_LINE
     }
 
     return Target(target);
@@ -92,7 +95,7 @@ Target Target::new_to_memory() {
     VipsTarget *target = vips_target_new_to_memory();
 
     if (target == nullptr) {
-        throw vips::VError();
+        throw vips::VError();  // LCOV_EXCL_LINE
     }
 
     return Target(target);

src/api/processors/mask.cpp

@@ -1,5 +1,6 @@
 #include "mask.h"
 
+#include "../io/blob.h"
 #include "../utils/utility.h"
 
 #include <algorithm>
@@ -15,6 +16,8 @@ namespace weserv::api::processors {
 using enums::MaskType;
 using parsers::Color;
 
+using io::Blob;
+
 std::string Mask::svg_path_by_type(const int width, const int height,
                                    const MaskType &mask,
                                    int *out_x_min, int *out_y_min,
@@ -323,10 +326,11 @@ VImage Mask::process(const VImage &image) const {
         auto svg_mask = svg.str();
 
         // We don't take a copy of the data or free it
-        auto *blob = vips_blob_new(nullptr, svg_mask.data(), svg_mask.size());
+        auto blob =
+            Blob(vips_blob_new(nullptr, svg_mask.data(), svg_mask.size()));
         auto mask = VImage::svgload_buffer(
-            blob, VImage::option()->set("access", VIPS_ACCESS_SEQUENTIAL));
-        vips_area_unref(reinterpret_cast<VipsArea *>(blob));
+            blob.get_blob(),
+            VImage::option()->set("access", VIPS_ACCESS_SEQUENTIAL));
 
         // Cutout via dest-in
         output_image = output_image.composite2(mask, VIPS_BLEND_MODE_DEST_IN);
@@ -353,10 +357,11 @@ VImage Mask::process(const VImage &image) const {
         auto svg_frame = svg.str();
 
         // We don't take a copy of the data or free it
-        auto *blob = vips_blob_new(nullptr, svg_frame.data(), svg_frame.size());
+        auto blob =
+            Blob(vips_blob_new(nullptr, svg_frame.data(), svg_frame.size()));
         auto frame = VImage::svgload_buffer(
-            blob, VImage::option()->set("access", VIPS_ACCESS_SEQUENTIAL));
-        vips_area_unref(reinterpret_cast<VipsArea *>(blob));
+            blob.get_blob(),
+            VImage::option()->set("access", VIPS_ACCESS_SEQUENTIAL));
 
         // Ensure image to composite is premultiplied sRGB
         frame = frame.premultiply();