Add support for reading from stdin/writing to stdout in filter mode

Note that kakoune still needs to read the whole buffer first, only
once stdin is closed can it execute the keys.

5 files changed, 124 insertions, 86 deletions

diff --git a/src/buffer_utils.cc b/src/buffer_utils.cc
index 7e9b7316..020f7b83 100644
--- a/src/buffer_utils.cc
+++ b/src/buffer_utils.cc
@@ -1,5 +1,6 @@
 #include "buffer_utils.hh"
 
+#include "buffer_manager.hh"
 #include "event_manager.hh"
 
 #include <sys/select.h>
@@ -24,6 +25,60 @@ CharCount get_column(const Buffer& buffer,
     return col;
 }
 
+Buffer* create_buffer_from_data(StringView data, StringView name,
+                                Buffer::Flags flags, time_t fs_timestamp)
+{
+    bool bom = false, crlf = false;
+
+    const char* pos = data.begin();
+    if (data.length() >= 3 and
+       data[0] == '\xEF' and data[1] == '\xBB' and data[2] == '\xBF')
+    {
+        bom = true;
+        pos = data.begin() + 3;
+    }
+
+    std::vector<String> lines;
+    while (pos < data.end())
+    {
+        const char* line_end = pos;
+        while (line_end < data.end() and *line_end != '\r' and *line_end != '\n')
+             ++line_end;
+
+        // this should happen only when opening a file which has no
+        // end of line as last character.
+        if (line_end == data.end())
+        {
+            lines.emplace_back(pos, line_end);
+            lines.back() += '\n';
+            break;
+        }
+
+        lines.emplace_back(pos, line_end + 1);
+        lines.back().back() = '\n';
+
+        if (line_end+1 != data.end() and *line_end == '\r' and *(line_end+1) == '\n')
+        {
+            crlf = true;
+            pos = line_end + 2;
+        }
+        else
+            pos = line_end + 1;
+    }
+
+    Buffer* buffer = BufferManager::instance().get_buffer_ifp(name);
+    if (buffer)
+        buffer->reload(std::move(lines), fs_timestamp);
+    else
+        buffer = new Buffer{name, flags, std::move(lines), fs_timestamp};
+
+    OptionManager& options = buffer->options();
+    options.get_local_option("eolformat").set<String>(crlf ? "crlf" : "lf");
+    options.get_local_option("BOM").set<String>(bom ? "utf-8" : "no");
+
+    return buffer;
+}
+
 Buffer* create_fifo_buffer(String name, int fd, bool scroll)
 {
     Buffer* buffer = new Buffer(std::move(name), Buffer::Flags::Fifo | Buffer::Flags::NoUndo);
diff --git a/src/buffer_utils.hh b/src/buffer_utils.hh
index c16b359f..0211a926 100644
--- a/src/buffer_utils.hh
+++ b/src/buffer_utils.hh
@@ -29,6 +29,10 @@ CharCount get_column(const Buffer& buffer,
 
 Buffer* create_fifo_buffer(String name, int fd, bool scroll = false);
 
+Buffer* create_buffer_from_data(StringView data, StringView name,
+                                Buffer::Flags flags,
+                                time_t fs_timestamp = InvalidTime);
+
 }
 
 #endif // buffer_utils_hh_INCLUDED
diff --git a/src/file.cc b/src/file.cc
index 7dab64ec..92cf6bec 100644
--- a/src/file.cc
+++ b/src/file.cc
@@ -3,6 +3,7 @@
 #include "assert.hh"
 #include "buffer.hh"
 #include "buffer_manager.hh"
+#include "buffer_utils.hh"
 #include "completion.hh"
 #include "debug.hh"
 #include "unicode.hh"
@@ -95,18 +96,8 @@ String compact_path(StringView filename)
     return filename.str();
 }
 
-String read_file(StringView filename)
+String read_fd(int fd)
 {
-    int fd = open(parse_filename(filename).c_str(), O_RDONLY);
-    if (fd == -1)
-    {
-        if (errno == ENOENT)
-            throw file_not_found(filename);
-
-        throw file_access_error(filename, strerror(errno));
-    }
-    auto close_fd = on_scope_end([fd]{ close(fd); });
-
     String content;
     char buf[256];
     while (true)
@@ -120,6 +111,21 @@ String read_file(StringView filename)
     return content;
 }
 
+String read_file(StringView filename)
+{
+    int fd = open(parse_filename(filename).c_str(), O_RDONLY);
+    if (fd == -1)
+    {
+        if (errno == ENOENT)
+            throw file_not_found(filename);
+
+        throw file_access_error(filename, strerror(errno));
+    }
+    auto close_fd = on_scope_end([fd]{ close(fd); });
+
+    return read_fd(fd);
+}
+
 Buffer* create_buffer_from_file(String filename)
 {
     filename = real_path(parse_filename(filename));
@@ -132,69 +138,20 @@ Buffer* create_buffer_from_file(String filename)
 
         throw file_access_error(filename, strerror(errno));
     }
+    auto close_fd = on_scope_end([&]{ close(fd); });
+
     struct stat st;
     fstat(fd, &st);
     if (S_ISDIR(st.st_mode))
-    {
-        close(fd);
         throw file_access_error(filename, "is a directory");
-    }
-    const char* data = (const char*)mmap(nullptr, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
-    auto cleanup = on_scope_end([&]{ munmap((void*)data, st.st_size); close(fd); });
-
-    const char* pos = data;
-    bool crlf = false;
-    bool bom  = false;
-    if (st.st_size >= 3 and
-       data[0] == '\xEF' and data[1] == '\xBB' and data[2] == '\xBF')
-    {
-        bom = true;
-        pos = data + 3;
-    }
-
-    std::vector<String> lines;
-    const char* end = data + st.st_size;
-    while (pos < end)
-    {
-        const char* line_end = pos;
-        while (line_end < end and *line_end != '\r' and *line_end != '\n')
-             ++line_end;
-
-        // this should happen only when opening a file which has no
-        // end of line as last character.
-        if (line_end == end)
-        {
-            lines.emplace_back(pos, line_end);
-            lines.back() += '\n';
-            break;
-        }
-
-        lines.emplace_back(pos, line_end + 1);
-        lines.back().back() = '\n';
 
-        if (line_end+1 != end and *line_end == '\r' and *(line_end+1) == '\n')
-        {
-            crlf = true;
-            pos = line_end + 2;
-        }
-        else
-            pos = line_end + 1;
-    }
-    Buffer* buffer = BufferManager::instance().get_buffer_ifp(filename);
-    if (buffer)
-        buffer->reload(std::move(lines), st.st_mtime);
-    else
-        buffer = new Buffer{filename, Buffer::Flags::File,
-                            std::move(lines), st.st_mtime};
-
-    OptionManager& options = buffer->options();
-    options.get_local_option("eolformat").set<String>(crlf ? "crlf" : "lf");
-    options.get_local_option("BOM").set<String>(bom ? "utf-8" : "no");
+    const char* data = (const char*)mmap(nullptr, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
+    auto unmap = on_scope_end([&]{ munmap((void*)data, st.st_size); });
 
-    return buffer;
+    return create_buffer_from_data({data, data + st.st_size}, filename, Buffer::Flags::File, st.st_mtime);
 }
 
-static void write(int fd, StringView data, StringView filename)
+static void write(int fd, StringView data)
 {
     const char* ptr = data.data();
     ssize_t count   = (int)data.length();
@@ -206,14 +163,12 @@ static void write(int fd, StringView data, StringView filename)
         count -= written;
 
         if (written == -1)
-            throw file_access_error(filename, strerror(errno));
+            throw file_access_error("fd: " + to_string(fd), strerror(errno));
     }
 }
 
-void write_buffer_to_file(Buffer& buffer, StringView filename)
+void write_buffer_to_fd(Buffer& buffer, int fd)
 {
-    buffer.run_hook_in_own_context("BufWritePre", buffer.name());
-
     const String& eolformat = buffer.options()["eolformat"].get<String>();
     StringView eoldata;
     if (eolformat == "crlf")
@@ -221,25 +176,31 @@ void write_buffer_to_file(Buffer& buffer, StringView filename)
     else
         eoldata = "\n";
 
+    if (buffer.options()["BOM"].get<String>() == "utf-8")
+        ::write(fd, "\xEF\xBB\xBF", 3);
+
+    for (LineCount i = 0; i < buffer.line_count(); ++i)
     {
-        int fd = open(parse_filename(filename).c_str(),
-                      O_CREAT | O_WRONLY | O_TRUNC, 0644);
-        if (fd == -1)
-            throw file_access_error(filename, strerror(errno));
-        auto close_fd = on_scope_end([fd]{ close(fd); });
+        // end of lines are written according to eolformat but always
+        // stored as \n
+        StringView linedata = buffer[i];
+        write(fd, linedata.substr(0, linedata.length()-1));
+        write(fd, eoldata);
+    }
+}
 
-        if (buffer.options()["BOM"].get<String>() == "utf-8")
-            ::write(fd, "\xEF\xBB\xBF", 3);
+void write_buffer_to_file(Buffer& buffer, StringView filename)
+{
+    buffer.run_hook_in_own_context("BufWritePre", buffer.name());
+
+    int fd = open(parse_filename(filename).c_str(),
+                  O_CREAT | O_WRONLY | O_TRUNC, 0644);
+    if (fd == -1)
+        throw file_access_error(filename, strerror(errno));
+    auto close_fd = on_scope_end([fd]{ close(fd); });
+
+    write_buffer_to_fd(buffer, fd);
 
-        for (LineCount i = 0; i < buffer.line_count(); ++i)
-        {
-            // end of lines are written according to eolformat but always
-            // stored as \n
-            StringView linedata = buffer[i];
-            write(fd, linedata.substr(0, linedata.length()-1), filename);
-            write(fd, eoldata, filename);
-        }
-    }
     if ((buffer.flags() & Buffer::Flags::File) and
         real_path(filename) == real_path(buffer.name()))
         buffer.notify_saved();
diff --git a/src/file.hh b/src/file.hh
index d26b160f..e1561ca9 100644
--- a/src/file.hh
+++ b/src/file.hh
@@ -28,9 +28,14 @@ String parse_filename(StringView filename);
 String real_path(StringView filename);
 String compact_path(StringView filename);
 
+String read_fd(int fd);
 String read_file(StringView filename);
+
 Buffer* create_buffer_from_file(String filename);
+
 void write_buffer_to_file(Buffer& buffer, StringView filename);
+void write_buffer_to_fd(Buffer& buffer, int fd);
+
 String find_file(StringView filename, memoryview<String> paths);
 
 time_t get_fs_timestamp(StringView filename);
diff --git a/src/main.cc b/src/main.cc
index a917848b..3ef17912 100644
--- a/src/main.cc
+++ b/src/main.cc
@@ -411,6 +411,19 @@ int run_filter(StringView keystr, memoryview<StringView> files)
 
         buffer_manager.delete_buffer(*buffer);
     }
+    if (not isatty(0))
+    {
+        Buffer* buffer = create_buffer_from_data(read_fd(0), "*stdin*", Buffer::Flags::None);
+        InputHandler input_handler{{ *buffer, Selection{} }};
+
+        for (auto& key : keys)
+            input_handler.handle_key(key);
+
+        write_buffer_to_fd(*buffer, 1);
+
+        buffer_manager.delete_buffer(*buffer);
+    }
+
     buffer_manager.clear_buffer_trash();
     return 0;
 }