odb: Error when streaming in too [few|many] bytes

diff --git a/include/git2/odb.h b/include/git2/odb.h
index 3e93a932ca1f9c323590148f9d5823d4b007650b..e50a2a1c198b4b8bb986e02046524571283a9d71 100644 (file)
--- a/include/git2/odb.h
+++ b/include/git2/odb.h
@@ -238,6 +238,9 @@ GIT_EXTERN(int) git_odb_open_wstream(git_odb_stream **out, git_odb *db, size_t s
 /**
  * Write to an odb stream
  *
+ * This method will fail as soon as the total number of
+ * received bytes exceeds the size declared with `git_odb_open_wstream()`
+ *
  * @param stream the stream
  * @param buffer the data to write
  * @param len the buffer's length
@@ -251,6 +254,9 @@ GIT_EXTERN(int) git_odb_stream_write(git_odb_stream *stream, const char *buffer,
  * The object will take its final name and will be available to the
  * odb.
  *
+ * This method will fail if the total number of received bytes
+ * differs from the size declared with `git_odb_open_wstream()`
+ *
  * @param out pointer to store the resulting object's id
  * @param stream the stream
  * @return 0 on success; an error code otherwise

diff --git a/include/git2/odb_backend.h b/include/git2/odb_backend.h
index bafeec047055450a20a4eb82898d7a666eae054e..e558bbb1c8feb3b149d4f89bd0b472cc939456e8 100644 (file)
--- a/include/git2/odb_backend.h
+++ b/include/git2/odb_backend.h
@@ -78,6 +78,9 @@ struct git_odb_stream {
        unsigned int mode;
        void *hash_ctx;
 
+       size_t declared_size;
+       size_t received_bytes;
+
        /**
         * Write at most `len` bytes into `buffer` and advance the
         * stream.
@@ -93,9 +96,13 @@ struct git_odb_stream {
         * Store the contents of the stream as an object with the id
         * specified in `oid`.
         *
-        * This method will *not* be invoked by libgit2 if the object pointed at
-        * by `oid` already exists in any backend. Libgit2 will however take care
-        * of properly disposing the stream through a call to `free()`.
+        * This method will *not* be invoked by libgit2 when:
+        *  - the object pointed at by `oid` already exists in any backend.
+        *      - the total number of received bytes differs from the size declared
+        *    with `git_odb_open_wstream()`
+        *
+        * Libgit2 will however take care of properly disposing the stream through
+        * a call to `free()`.
         */
        int (*finalize_write)(git_odb_stream *stream, const git_oid *oid);
 

diff --git a/src/odb.c b/src/odb.c
index dfb252178da7e50c8b363fadb40b0411eef1fd48..2e6869547872ce4c35749934e812abb633efdf8c 100644 (file)
--- a/src/odb.c
+++ b/src/odb.c
@@ -888,17 +888,44 @@ int git_odb_open_wstream(
        hash_header(ctx, size, type);
        (*stream)->hash_ctx = ctx;
 
+       (*stream)->declared_size = size;
+       (*stream)->received_bytes = 0;
+
        return error;
 }
 
+static int git_odb_stream__invalid_length(
+       const git_odb_stream *stream,
+       const char *action)
+{
+       giterr_set(GITERR_ODB,
+               "Cannot %s - "
+               "Invalid length. %"PRIuZ" was expected. The "
+               "total size of the received chunks amounts to %"PRIuZ".",
+               action, stream->declared_size, stream->received_bytes);         
+
+       return -1;
+}
+
 int git_odb_stream_write(git_odb_stream *stream, const char *buffer, size_t len)
 {
        git_hash_update(stream->hash_ctx, buffer, len);
+
+       stream->received_bytes += len;
+
+       if (stream->received_bytes > stream->declared_size)
+               return git_odb_stream__invalid_length(stream,
+                       "stream_write()");
+
        return stream->write(stream, buffer, len);
 }
 
 int git_odb_stream_finalize_write(git_oid *out, git_odb_stream *stream)
 {
+       if (stream->received_bytes != stream->declared_size)
+               return git_odb_stream__invalid_length(stream,
+                       "stream_finalize_write()");
+
        git_hash_final(out, stream->hash_ctx);
 
        if (git_odb_exists(stream->backend->odb, out))

diff --git a/tests-clar/odb/streamwrite.c b/tests-clar/odb/streamwrite.c
new file mode 100644 (file)
index 0000000..591a200
--- /dev/null
+++ b/tests-clar/odb/streamwrite.c
@@ -0,0 +1,56 @@
+#include "clar_libgit2.h"
+#include "git2/odb_backend.h"
+
+static git_repository *repo;
+static git_odb *odb;
+static git_odb_stream *stream;
+
+void test_odb_streamwrite__initialize(void)
+{
+       repo = cl_git_sandbox_init("testrepo.git");
+       cl_git_pass(git_repository_odb(&odb, repo));
+
+       cl_git_pass(git_odb_open_wstream(&stream, odb, 14, GIT_OBJ_BLOB));
+       cl_assert_equal_sz(14, stream->declared_size);
+}
+
+void test_odb_streamwrite__cleanup(void)
+{
+       git_odb_stream_free(stream);
+       git_odb_free(odb);
+       cl_git_sandbox_cleanup();
+}
+
+void test_odb_streamwrite__can_accept_chunks(void)
+{
+       git_oid oid;
+
+       cl_git_pass(git_odb_stream_write(stream, "deadbeef", 8));
+       cl_assert_equal_sz(8, stream->received_bytes);
+
+       cl_git_pass(git_odb_stream_write(stream, "deadbeef", 6));
+       cl_assert_equal_sz(8 + 6, stream->received_bytes);
+
+       cl_git_pass(git_odb_stream_finalize_write(&oid, stream));
+}
+
+void test_odb_streamwrite__can_detect_missing_bytes(void)
+{
+       git_oid oid;
+
+       cl_git_pass(git_odb_stream_write(stream, "deadbeef", 8));
+       cl_assert_equal_sz(8, stream->received_bytes);
+
+       cl_git_pass(git_odb_stream_write(stream, "deadbeef", 4));
+       cl_assert_equal_sz(8 + 4, stream->received_bytes);
+
+       cl_git_fail(git_odb_stream_finalize_write(&oid, stream));
+}
+
+void test_odb_streamwrite__can_detect_additional_bytes(void)
+{
+       cl_git_pass(git_odb_stream_write(stream, "deadbeef", 8));
+       cl_assert_equal_sz(8, stream->received_bytes);
+
+       cl_git_fail(git_odb_stream_write(stream, "deadbeef", 7));
+}