[release/5.0-preview4] Revert processing bundles in framework (#35679)v5.0.0-preview.4.20251.6

This commit reverts:
Revert "Single-File: Process bundles in the framework (#34274)"
This reverts commit 78b303df8fbb242985d049a277d0d199cafd51b5.

Revert "Single-File Bundler: Add a FileSize test (#35149)"
This reverts commit 779588a509b81d909ac5d496c172949ec1f1ddcc.

*Customer Scenario*

Publishing apps as a self-contained single-file doesn't work as expected.

* Publish needs to generate hostpolicy and hostfxr separate from the single file bundle
* Cross-platform publishing is incorrect

*Problem*

Since Static-apphost is not yet ready, processing bundle content in hostpolicy means that  hostpolicy and hostfxr DLLs need to be separate from the bundle. This causes self-contained single-file apps to not be a "single file" temporarily. 

The change also requires supporting changes from the SDK, to publish hostfxr and hostpolicy as separate files, and to invoke HostModel library with arguments that facilitate cross-platform publishing.

*Solution*

To solve these, problem, this change reverts:

Revert "Single-File: Process bundles in the framework (#34274)" commit 78b303df8fbb242985d049a277d0d199cafd51b5.

and a dependent test-only change:

Revert "Single-File Bundler: Add a FileSize test (#35149)" commit 779588a509b81d909ac5d496c172949ec1f1ddcc.

*Risk*

Medium
The change is contained to only host components: apphost, hostpolicy, and hostfxr.
However, the change is big, and needs testing in runtime and SDK repos.

*Testing*

Manually tested the SDK by inserting apphost, hostfxr, hostpolicy, and hostmodel library from this build into the `dotnet/packs` preview-4 SDK from https://github.com/dotnet/sdk/pull/11518 build.

Verified that:
* Singlefile apps can be published and run OK for  { Windows, Linux, Osx } x {netcoreapp3.0, netcoreapp3.1, netcoreapp5.0} 
* Cross-targeting builds of single-file apps build and run OK (ex: built on Windos, run on Mac).

1 files changed, 16 insertions, 46 deletions

diff --git a/src/installer/corehost/cli/json_parser.cpp b/src/installer/corehost/cli/json_parser.cpp
index c6f0cbbf0c9..9814f3215d6 100644
--- a/src/installer/corehost/cli/json_parser.cpp
+++ b/src/installer/corehost/cli/json_parser.cpp
@@ -42,9 +42,9 @@ std::streampos get_utf8_bom_length(pal::istream_t& stream)
     return 3;
 }
 
-void get_line_column_from_offset(const char* data, uint64_t size, size_t offset, int *line, int *column)
+void get_line_column_from_offset(const std::vector<char>& json, size_t offset, int *line, int *column)
 {
-    assert(offset < size);
+    assert(offset < json.size());
 
     *line = *column = 1;
 
@@ -52,12 +52,12 @@ void get_line_column_from_offset(const char* data, uint64_t size, size_t offset,
     {
         (*column)++;
 
-        if (data[i] == '\n')
+        if (json[i] == '\n')
         {
             (*line)++;
             *column = 1;
         }
-        else if (data[i] == '\r' && data[i + 1] == '\n')
+        else if (json[i] == '\r' && json[i + 1] == '\n')
         {
             (*line)++;
             *column = 1;
@@ -75,30 +75,32 @@ void json_parser_t::realloc_buffer(size_t size)
     m_json[size] = '\0';
 }
 
-bool json_parser_t::parse_json(char* data, int64_t size, const pal::string_t& context)
+bool json_parser_t::parse_json(const pal::string_t& context)
 {
+    assert(!m_json.empty());
+
 #ifdef _WIN32
     // Can't use in-situ parsing on Windows, as JSON data is encoded in
     // UTF-8 and the host expects wide strings.  m_document will store
     // data in UTF-16 (with pal::char_t as the character type), but it
     // has to know that data is encoded in UTF-8 to convert during parsing.
     constexpr auto flags = rapidjson::ParseFlag::kParseStopWhenDoneFlag
-        | rapidjson::ParseFlag::kParseCommentsFlag;
-    m_document.Parse<flags, rapidjson::UTF8<>>(data);
-#else // _WIN32
-    m_document.ParseInsitu<rapidjson::ParseFlag::kParseCommentsFlag>(data);
-#endif // _WIN32
+                         | rapidjson::ParseFlag::kParseCommentsFlag;
+    m_document.Parse<flags, rapidjson::UTF8<>>(m_json.data());
+#else
+    m_document.ParseInsitu<rapidjson::ParseFlag::kParseCommentsFlag>(m_json.data());
+#endif
 
     if (m_document.HasParseError())
     {
         int line, column;
         size_t offset = m_document.GetErrorOffset();
 
-        get_line_column_from_offset(data, size, offset, &line, &column);
+        get_line_column_from_offset(m_json, offset, &line, &column);
 
         trace::error(_X("A JSON parsing exception occurred in [%s], offset %zu (line %d, column %d): %s"),
-            context.c_str(), offset, line, column,
-            rapidjson::GetParseError_En(m_document.GetParseError()));
+                     context.c_str(), offset, line, column,
+                     rapidjson::GetParseError_En(m_document.GetParseError()));
         return false;
     }
 
@@ -128,37 +130,5 @@ bool json_parser_t::parse_stream(pal::istream_t& stream,
     realloc_buffer(stream_size - current_pos);
     stream.read(m_json.data(), stream_size - current_pos);
 
-    return parse_json(m_json.data(), m_json.size(), context);
-}
-
-bool json_parser_t::parse_file(const pal::string_t& path)
-{
-    // This code assumes that the caller has checked that the file `path` exists
-    // either within the bundle, or as a real file on disk.
-    assert(m_bundle_data == nullptr);
-    assert(m_bundle_location == nullptr);
-
-    if (bundle::info_t::is_single_file_bundle())
-    {
-        m_bundle_data = bundle::info_t::config_t::map(path, m_bundle_location);
-        // The mapping will be unmapped by the json_parser destructor.
-        // The mapping cannot be immediately released due to in-situ parsing on Linux. 
-
-        if (m_bundle_data != nullptr)
-        {
-            bool result = parse_json(m_bundle_data, m_bundle_location->size, path);
-            return result;
-        }
-    }
-
-    pal::ifstream_t file{ path };
-    return parse_stream(file, path);
-}
-
-json_parser_t::~json_parser_t()
-{
-    if (m_bundle_data != nullptr)
-    {
-        bundle::info_t::config_t::unmap(m_bundle_data, m_bundle_location);
-    }
+    return parse_json(context);
 }