[librsvg] xml2.rs: Minimal binding to the parts of libxml2 we need

[Federico Mena Quintero <federico src gnome org>]

commit 42408e5d6439a2637ffe28fa2051bcdedb928727
Author: Federico Mena Quintero <federico gnome org>
Date:   Tue Dec 4 17:09:47 2018 -0600

    xml2.rs: Minimal binding to the parts of libxml2 we need

 Makefile.am                |   3 +-
 rsvg_internals/src/lib.rs  |   1 +
 rsvg_internals/src/xml2.rs | 211 +++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 214 insertions(+), 1 deletion(-)
---
diff --git a/Makefile.am b/Makefile.am
index cb67d101..5ec0fbdc 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -119,7 +119,8 @@ RUST_SRC =                                                  \
        rsvg_internals/src/util.rs                              \
        rsvg_internals/src/viewbox.rs                           \
        rsvg_internals/src/viewport.rs                          \
-       rsvg_internals/src/xml.rs
+       rsvg_internals/src/xml.rs                               \
+       rsvg_internals/src/xml2.rs
 
 RUST_EXTRA =                                           \
        Cargo.lock                                      \
diff --git a/rsvg_internals/src/lib.rs b/rsvg_internals/src/lib.rs
index 3142e629..6d218da4 100644
--- a/rsvg_internals/src/lib.rs
+++ b/rsvg_internals/src/lib.rs
@@ -144,3 +144,4 @@ mod util;
 mod viewbox;
 mod viewport;
 mod xml;
+mod xml2;
diff --git a/rsvg_internals/src/xml2.rs b/rsvg_internals/src/xml2.rs
new file mode 100644
index 00000000..b1ac7362
--- /dev/null
+++ b/rsvg_internals/src/xml2.rs
@@ -0,0 +1,211 @@
+// This is a hand-written binding to the very minimal part of libxml2 that we need.
+
+#![allow(non_snake_case, non_camel_case_types)]
+#![cfg_attr(rustfmt, rustfmt_skip)]
+
+use glib_sys::gpointer;
+use libc;
+
+pub const XML_CHAR_ENCODING_NONE: libc::c_int = 0;
+
+pub const XML_INTERNAL_GENERAL_ENTITY: libc::c_int = 1;
+
+pub const XML_PARSE_NONET:     libc::c_int = 1 << 11;
+pub const XML_PARSE_HUGE:      libc::c_int = 1 << 19;
+pub const XML_PARSE_BIG_LINES: libc::c_int = 1 << 22;
+
+pub type xmlDocPtr = gpointer;
+
+pub type xmlEntityPtr = gpointer;
+
+#[repr(C)]
+pub struct xmlSAXHandler {
+    pub internalSubset: gpointer,
+    pub isStandalone: gpointer,
+    pub hasInternalSubset: gpointer,
+    pub hasExternalSubset: gpointer,
+    pub resolveEntity: gpointer,
+    pub getEntity: Option<unsafe extern "C" fn(
+        ctx: *mut libc::c_void,
+        name: *const libc::c_char,
+    ) -> xmlEntityPtr>,
+
+    pub entityDecl: Option<unsafe extern "C" fn(
+        ctx: *mut libc::c_void,
+        name: *const libc::c_char,
+        type_: libc::c_int,
+        public_id: *const libc::c_char,
+        system_id: *const libc::c_char,
+        content: *const libc::c_char,
+    )>,
+
+    pub notationDecl: gpointer,
+    pub attributeDecl: gpointer,
+    pub elementDecl: gpointer,
+
+    pub unparsedEntityDecl: Option<unsafe extern "C" fn(
+        ctx: *mut libc::c_void,
+        name: *const libc::c_char,
+        public_id: *const libc::c_char,
+        system_id: *const libc::c_char,
+        notation_name: *const libc::c_char,
+    )>,
+
+    pub setDocumentLocator: gpointer,
+    pub startDocument: gpointer,
+    pub endDocument: gpointer,
+
+    pub startElement: Option<unsafe extern "C" fn(
+        ctx: *mut libc::c_void,
+        name: *const libc::c_char,
+        atts: *const *const libc::c_char,
+    )>,
+
+    pub endElement: Option<unsafe extern "C" fn(
+        ctx: *mut libc::c_void,
+        name: *const libc::c_char,
+    )>,
+
+    pub reference: gpointer,
+
+    pub characters: Option<unsafe extern "C" fn(
+        ctx: *mut libc::c_void,
+        ch: *const libc::c_char,
+        len: libc::c_int,
+    )>,
+
+    pub ignorableWhitespace: gpointer,
+
+    pub processingInstruction: Option<unsafe extern "C" fn(
+        ctx: *mut libc::c_void,
+        target: *const libc::c_char,
+        data: *const libc::c_char,
+    )>,
+
+    pub comment: gpointer,
+    pub warning: gpointer,
+
+    pub error: gpointer,
+
+    pub fatalError: gpointer,
+
+    pub getParameterEntity: Option<unsafe extern "C" fn(
+        ctx: *mut libc::c_void,
+        name: *const libc::c_char,
+    ) -> xmlEntityPtr>,
+
+    pub cdataBlock: Option<unsafe extern "C" fn(
+        ctx: *mut libc::c_void,
+        value: *const libc::c_char,
+        len: libc::c_int,
+    )>,
+
+    pub externalSubset: gpointer,
+
+    pub initialized: libc::c_uint,
+
+    pub _private: gpointer,
+    pub startElementNs: gpointer,
+    pub endElementNs: gpointer,
+    pub serror: gpointer,
+}
+
+pub type xmlSAXHandlerPtr = *mut xmlSAXHandler;
+
+// The original struct _xmlParserCtxt in libxml2 has a *ton* of
+// fields; mostly are implementation details.  We only require access
+// to fields up to replaceEntities, so we'll represent up to that
+// field, and ignore subsequent ones.  This struct is used just to
+// cast the xmlParserCtxtPtr that we get out of libxml2 into a
+// Rust-visible structure; we don't need a complete representation of the
+// original struct.
+#[repr(C)]
+pub struct xmlParserCtxt {
+    pub sax: gpointer,
+    pub userData: gpointer,
+    pub myDoc: xmlDocPtr,
+    pub wellFormed: libc::c_int,
+    pub replaceEntities: libc::c_int,
+    // ... libxml2 has more fields here; we don't use them
+}
+
+pub type xmlParserCtxtPtr = *mut xmlParserCtxt;
+
+#[repr(C)]
+pub struct xmlError {
+    pub domain: libc::c_int,
+    pub code: libc::c_int,
+    pub message: *const libc::c_char,
+    pub level: libc::c_int,
+    pub file: *const libc::c_char,
+    pub line: libc::c_int,
+    pub str1: *const libc::c_char,
+    pub str2: *const libc::c_char,
+    pub str3: *const libc::c_char,
+    pub int1: libc::c_int,
+    pub int2: libc::c_int,
+    pub ctxt: gpointer,
+    pub node: gpointer,
+}
+
+pub type xmlErrorPtr = *mut xmlError;
+
+pub type xmlInputReadCallback = Option<unsafe extern "C" fn(
+    context: *mut libc::c_void,
+    buffer: *const libc::c_char,
+    len: libc::c_int,
+) -> libc::c_int>;
+
+pub type xmlInputCloseCallback = Option<unsafe extern "C" fn(
+    context: *mut libc::c_void,
+) -> libc::c_int>;
+
+pub type xmlCharEncoding = libc::c_int;
+
+extern "C" {
+    pub fn xmlCreatePushParserCtxt(
+        sax: xmlSAXHandlerPtr,
+        user_data: *mut libc::c_void,
+        chunk: *const libc::c_char,
+        size: libc::c_int,
+        filename: *const libc::c_int,
+    ) -> xmlParserCtxtPtr;
+
+    pub fn xmlCreateIOParserCtxt(
+        sax: xmlSAXHandlerPtr,
+        user_data: *mut libc::c_void,
+        ioread: xmlInputReadCallback,
+        ioclose: xmlInputCloseCallback,
+        ioctx: *mut libc::c_void,
+        enc: xmlCharEncoding,
+    ) -> xmlParserCtxtPtr;
+
+    pub fn xmlParseChunk(
+        ctxt: xmlParserCtxtPtr,
+        chunk: *const libc::c_char,
+        size: libc::c_int,
+        terminate: libc::c_int,
+    ) -> libc::c_int;
+
+    pub fn xmlParseDocument(ctxt: xmlParserCtxtPtr) -> libc::c_int;
+
+    pub fn xmlFreeDoc(doc: xmlDocPtr);
+
+    pub fn xmlFreeParserCtxt(ctxt: xmlParserCtxtPtr);
+
+    pub fn xmlCtxtGetLastError(ctxt: *mut libc::c_void) -> xmlErrorPtr;
+
+    pub fn xmlCtxtUseOptions(
+        ctxt: xmlParserCtxtPtr,
+        options: libc::c_int,
+    ) -> libc::c_int;
+
+    pub fn xmlNewEntity(
+        doc: xmlDocPtr,
+        name: *const libc::c_char,
+        type_: libc::c_int,
+        external_id: *const libc::c_char,
+        system_id: *const libc::c_char,
+        content: *const libc::c_char,
+    ) -> xmlEntityPtr;
+}